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Flashcards in 1 - SYSTEMIC ANTIBACTERIAL AGENTS Deck (264):
1

Owing to the increased prevalence of uncomplicated skin and soft tissue infections (USSTI) caused by community-acquired MRSA, there has been changes to the antibiotic prescribing pattern such that there is increase use of doxycycline, minocycline and bactrim (trimethoprim-sulfamethoxazole), and a decrease in the use of oral cephalosporin therapy

True

2

Penicillins are bactericidal and inhibit synthesis of the bacterial cell wall

True

3

Cephalosporins are bactericidal and inhibit synthesis of the bacterial cell wall

True

4

Combination Beta-lactams (penicillins) and beta-lactamase inhibitor antibiotics are bactericidal and inhibit synthesis of the bacterial cell wall

True (amoxicillin-clavulanate, ticarcillin-clavulanate, piperacillin-clavulanate)

5

Vancomycin is both bactericidal (against staphylococci and streptococci) and bacteriostatic (against most enterococci) against gram +Ve organisms only and inhibits synthesis of the bacterial cell wall

True

6

Macrolides (clarithromycin, erythromycin, azithromycin) are bacteriostatic against most gram +Ve organisms except MRSA and enterococcus, as they inhibit bacterial protein synthesis

True

7

Fluoroquinolones are bactericidal against most gram -Ve organisms pseudomonas, enterobacteriaceae, bacillus anthrax (ciprofloxacin) and variable efficacy against gram +Ve organisms staph aureus and strep pyogenes (levofloxacin, moxifloxacin) by interfering with bacterial DNA replication

True

8

Tetracyclines (tetracycline, doxycycline, minocycline) are bacteriostatic in that they possess greater gram +Ve than gram -Ve activity by inhibiting bacterial protein synthesis

True (binding to 30s subunit of the bacterial ribosome)

9

Rifampicin (a rifamycin antibiotic) is bactericidal with activity against mycobacteria and gram +Ve organisms and poor gram -Ve coverage by preventing bacterial protein synthesis

True

10

The folate-synthesis inhibitor bactrim (trimethoprim-sulfamethoxazole) is bacteriostatic against many gram +Ve cocci, pseudomonas and PCP by inhibiting bacterial protein synthesis

True

11

The Lincosamide Clindamycin is bacteriostatic against several gram +Ve cocci and a wide variety of anaerobes by reducing bacterial protein synthesis

True

12

Penicillin G (IV and IM) and Penicillin V (PO) are first generation natural penicillins (bactericidal) with activity against gram +Ve cocci and rods, gram -Ve cocci and anaerobes, but are ineffective against MSSA and MRSA

True (dicloxacillin, nafcillin, oxacillin are semi-synthetic first generation penicillins)

13

Dicloxacillin, nafcillin, oxacillin are semi-synthetic first generation beta-lactamase resistant penicillins (bactericidal) exhibit activity against MSSA and other gram +Ve cocci such as streptococcus pyogenes, but MRSA developed subsequently

True (penicillin G and penicillin V are natural first generation penicillins)

14

Amoxicillin and ampicillin (aminopenicillins) are second generation penicillins (bactericidal) with extended activity against gram -Ve bacilli

True

15

Ticarcillin (carboxypenicillin) is a third generation extended spectrum penicillin (bactericidal) with anti-pseudomonal activity

True

16

Piperacillin (ureidopenicillin) is a fourth generation extended spectrum penicillin (bactericidal) with anti-pseudomonal activity

True

17

Amoxicillin-clavulanate and ampicillin-sulbactam are combination second generation/beta-lactamase inhibitors (bactericidal)

True

18

Ticarcillin-clavulanate is a combination third generation carboxypenicillin/beta-lactamase inhibitor (bactericidal)

True

19

Piperacillin-tazobactam is a fourth generation ureidopenicillin/beta-lactamase inhibitor (bactericidal)

True

20

Staph aureus (gram +Ve coccus) and many enterobacteriaceae (gram -Ve rods) species bacteria produce beta-lactamase enzyme which hydrolyses beta-lactam penicillins (first generation semi-synthetic penicillins Dicloxacillin, nafcillin and oxacillin are beta-lactamase resistant), rendering these antibiotics ineffective

True (therefore some beta-lactam penicillins have been combined with a beta-lactamase inhibitor to produce resistance of the antibiotics to degradation by beta-lactamase enzyme)

21

All beta-lactams (penicillins and cephalosporins) are excreted renally except nafcillin, oxacillin and piperacillin

True (nafcillin, oxacillin and piperacillin are eliminated through the biliary system)

22

Beta-lactams (penicillins and cephalosporins) are more commonly associated with drug-induced hypersensitivity reactions with the severity ranging from exanthematous eruptions, to urticarial eruptions to fatal anaphylaxis

True (Penicillin G is the first reported to cause a hypersensitivity reaction, with amoxicillin most commonly implicated agent more recently)

23

A skin eruption that is not truly allergic in origin may arise when ampicillin is given to patients with infectious mononucleosis or lymphocytic leukaemia or when it is co-administered with allopurinol, therefore this unique ampicillin eruption is not believed to be a contraindication to treatment with other penicillins at a later date

True (the eruption is generalised, maculopapular and pruritic, and typically manifests within 7-10 days after the initiation of ampicillin with usual persistence for up to 1 week after ampicillin in discontinued)

24

In patients with a history of severe and life-threatening allergic reaction to a penicillin or cephalosporin, avoidance of the other drugs in these 2 general categories is advised

True (for practical purposes it should be assumed that all penicillins cross-react, and that if they have a true allergic reaction to one form of penicillin they may react to all penicillins and possibly to cephalosporins as well)

25

The aminopenicillins (amoxicillin and ampicillin) appear to be associated with a higher incidence of allergic reactions than other penicillins

True

26

GI upset including nausea and antibiotic-associated diarrhoea are not uncommon with penicillins

True (yoghurt or other means of lactobacillus ingestion may be a helpful adjuvant to prevent diarrhoea-related complications due to alterations in normal gut flora)

27

C. diff colitis can occur with penicillins

True

28

Shore nails (transverse leuconychia and onychomadesis/nail shedding following drug-induced erythroderma) have been seen with Dicloxacillin

True

29

Onychomadesis (nail shedding) and photo-onycholysis have been noted following dicloxacillin use

True

30

Cholestasis associated with penicillins is uncommon

True

31

Probenecid prolongs the renal excretion of penicillin and penicillin-beta lactamase antibiotics

True (result in an increase in serum concentration due to delayed renal excretion)

32

Oral antibiotics including beta-lactams (penicillins and cephalosporins) may potentially alter the anticoagulant effects of warfarin

True

33

Penicillins and cephalosporins are beta-lactam antibiotics

True

34

As oppose to penicillins which are also beta-lactams, the structure of beta-lactam cephalosporins gives it resistance to beta-lactamase enzymes

True

35

There are 5 generations of cephalosporins (beta-lactams) based on their general spectrum of antimicrobial activity

True

36

Cefazolin (IM/IV) and cephalexin (PO) are first generation cephalosporins which are most active of all the cephalosporins against gram +Ve staphylococci and non-enterococcal streptococci, and are active against many of the oral anaerobes except the Bacteroides fragilis group

True

37

Cefazolin (IM/IV) and cephalexin (PO) are first generation cephalosporins which are resistant to MRSA, streptococcus pneumoniae and gram -Ve organisms (haemophilus influenzae and enterococci, pseudomonas) and nosocomial gram -Ve infections

True

38

Cefuroxime (IV/IM/PO) and cefaclor (PO) are second generation true cephalosporins which demonstrate increased gram -Ve activity (against haemophilus influenzae, moraxella catarrhalis, neisseria meningitidis, neisseria gonorrhoea and some enterobacteriacea) and decreased gram +Ve activity

True (second generation cephamycins such as cefoxitin IV/IM are not 'true' cephalosporins and have inferior activity against gram +Ve staph and strep, but are effective against Bacteroides fragilis)

39

Third, forth and fifth generation cephalosporins have anti-pseudomonal activity

True

40

Third generation cephalosporins demonstrate less consistent activity against gram +Ve organisms and an increased spectrum of gram -Ve activity due to beta-lactamase stability, and some have anti-pseudomonal activity

True

41

Fifth generation cephalosporins have shown activity against MRSA, VRSA and MSSA and pseudomonas

True

42

Cephalexin (first generation cephalosporin) is best absorbed from an empty stomach

True

43

The bioavailability of Cefuroxime (second generation cephalosporin) is increased when taken with food

True (in contrast with first generation cephalosporin cephalexin where it is best absorbed from an empty stomach)

44

First and second generation cephalosporins including cephalexin are excreted primarily by the kidneys and dosage adjustments are recommended for patients with significant renal insufficiency

True

45

The short half life of cephalexin (less than 1 hour) may be associated with bacterial resistance if given less than TDS or QID dosing

True

46

GI effects such as nausea, vomiting, diarrhoea are relatively frequent with cephalosporins; although unlike its beta-lactam counterpart penicillins, antibiotic-associated C. diff colitis is much less common

True

47

Mild elevation of liver transaminases may occur with cephalosporins, although serious hepatic injury is rare

True

48

Potential cross-reactivity of cephalosporins with penicillins has been traditionally stated to occur in 5-10% of penicillin-allergic individuals, and cephalosporin-allergic reactions occur more commonly in patients with a history of penicillin allergy vs those without penicillin allergy

True (the degree of cross-reactivity likely depends on the generation of cephalosporin and very likely is due to the structural similarities/differences with penicillins I.e. In early first generation cephalosporins which sometimes contain trace amounts of penicillins)

49

Cephalosporin use should be avoided in patients with a history of an immediate or accelerated reaction to penicillin (IgE-mediated or severe type IV delayed hypersensitivity reactions)

True (cephalosporin skin testing is much less reliable than penicillin skin testing to evaluate hypersensitivity reactions)

50

Cephalosporin may cause vaginal candidiasis

True

51

Acute paronychia has been described following treatment with cephalexin

True

52

Drug-induced immune-mediated haemolytic anaemia have been associated with ceftriaxone (third generation cephalosporin) and piperacillin (forth generation penicillin)

True

53

Nephrotoxicity is rare in cephalosporins, but dose reduction of most cephalosporins is recommended in patients with renal insufficiency

True

54

Cephalosporins (such as the cephamycin antibiotic cefotetan) with the NMTT ring have been reported to induce a disulfiram-like reaction with alcohol ingestion

True

55

Cephalosporins (such as the cephamycin antibiotic cefotetan) with the NMTT ring can also prolong prothrombin times as it inhibits production of vitamin-K clotting factors and could be an issue in patients on anticoagulation therapy such as warfarin

True

56

Probenecid competes with renal tubular secretion of some cephalosporins and may increase and prolong the plasma levels for cephalosporins

True

57

Some cephalosporins may increase the risk of nephrotoxicity when co-administered with aminoglycosides (gentamicin) or potent diuretics

True

58

In patients with renal impairment, the half-life of beta-lactam/beta-lactamase combination of drugs is prolonged and blood levels are elevated, thus warranting dosage adjustment in some cases

True

59

The recommended oral agent for the treatment of animal or human bites infected by combined aerobic and anaerobic pathogens is amoxicillin-clavulanate

True

60

Adverse effects most often associated with amoxicillin-clavulanate and piperacillin-tazabactam are GI effects especially diarrhoea

True (diarrhoea occurs less frequently when amoxicillin-clavulanate is administered with food)

61

Hypersensitivity reactions from the beta-lactam/beta-lactamase antibiotics are similar to those seem from the beta-lactam (penicillins and cephalosporins) antibiotics alone

True

62

Ticarcillin and piperacillin can prolong bleeding times and cause platelet aggregation dysfunction

True

63

Ticarcillin and piperacillin can cause hypernatraemia, transient elevation of transaminases, thrombocytopenia, neutropenia and eosinophilia

True

64

Carbapenems (imipenem) demonstrate the most complete range of antibacterial coverage of any antibiotic class

True

65

There is a high degree of cross-reactivity between Carbapenems (imipenem) and penicillin

True (the incidence of allergic-type reactions to a carbapenem is 5.2 times greater in patient who were reportedly allergic to penicillin)

66

Monobactams (aztreonam) has an antibacterial spectrum activity limited to aerobic gram -Ve organisms and has been employed as a sole agent in treating gram -Ve cutaneous infections in conjunction with other drugs that inhibit gram +Ve or anaerobic flora

True

67

Monobactams (aztreonam) has an adverse effect profile similar to that of other beta-lactam antibiotics (penicillins and cephalosporins) including rare cases of erythema multiforme, TEN, urticarial eruptions and exfoliative dermatitis

True (however patients who are allergic to penicillin can be safely given aztreonam)

68

Patients who are allergic to penicillin can be safely given aztreonam

True

69

Vancomycin is clinically important in the treatment of MRSA

True

70

Vancomycin is administered IV because of minimal absorption from the GI tract and is used PO only for the treatment of C. Diff diarrhoea

True

71

90-100% of vancomycin is excreted by glomerular filtration in the kidneys, therefore dosage modification is recommended in patients with marked renal insufficiency

True

72

Red man syndrome and shock secondary to histamine release can be caused by rapid transfusion of vancomycin

True

73

Vancomycin is one of the most common causes of drug-induced linear IgA bullous dermatosis, developing after the initiation of vancomycin and also upon re-challenge

True (as vancomycin may rarely cause TEN, differentiation of TEN from vancomycin-induced linear IgA bullous dermatosis needs to be differentiated as multiple cases of vancomycin-induced linear IgA bullous dermatosis have been reported as these have presented as exanthematous eruption without blistering)

74

Vancomycin dose-related hearing loss/ototoxicity has been reported in patients with renal failure, likely due to reduced excretion of vancomycin leading to accumulation of the drug

True

75

Vancomycin has caused nephrotoxicity particularly when administered along with aminoglycoside antibiotics (gentamicin)

True

76

Macrolides have antibacterial and anti-inflammatory properties

True (anti-inflammatory properties contribute towards their therapeutic benefit in inflammatory facial dermatoses such as acne and Rosacea)

77

Erythromycin is the prototype macrolide

True (other macrolides which are in fact azalides include clarithromycin and azithromycin)

78

Clarithromycin and azithromycin are azalide antibiotics (class of macrolide antibiotics)

True

79

In the management of acne vulgaris, the use of oral erythromycin has markedly declined due to the widespread emergence of resistant P. acnes strains, with resistance rates as high as 50%

True

80

PO erythromycin has an erratic oral bioavailability and a short half-life requiring frequent administration

True

81

PO erythromycin is associated with frequent GI adverse effects such as nausea, abdominal discomfort and diarrhoea

True (erythromycin binds to motilin receptors throughout the GI tract, releasing motilin which stimulates migrating digestive contractions thus inducing a higher incidence of GI disturbance than with the azalide subcategory)

82

Erythromycin (and to a lesser extent clarithromycin) is a CYP3A4 and CYP1A2 inhibitor which leads to reduced clearance and increased risk of toxicity of a wide variety of drugs

True

83

Clarithromycin is 2-4 times more potent than erythromycin against gram +Ve organisms such as staphylococci and streptococci

True

84

Unlike erythromycin, clarithromycin and azithromycin possess increased activity against several gram -Ve pathogens including H. Influenzae

True

85

Both clarithromycin and azithromycin are affective against atypical mycobacteria such as Mycobacterium avium-intracellulare, Mycobacterium Leprae, and Mycobacterium chelonei

True (Clarithromycin is most effective against M. Leprae which causes leprosy)

86

Both clarithromycin and azithromycin demonstrate activity against Toxoplasma gondii, Treponema pallidum (cause of syphilis) and Borrelia burgdoferi

True

87

Azithromycin also has activity against organisms contracted from animal bites and human bites

True (similar to amoxicillin-clavulanate)

88

Azithromycin has activity against E. Coli, N. Gonorrhoea, chlamydia trachomatis

True

89

Unless administered in an enteric coated form, erythromycin is vulnerable to gastric acid inactivation and must be taken on an empty stomach

True

90

Clarithromycin and azithromycin (azalides class of macrolide antibiotics) have improved bioavailability than erythromycin with clarithromycin equally well absorbed with or without food, although azithromycin absorption in decreased with food

True

91

Both clarithromycin and erythromycin are excreted by the kidneys and dosages of both drugs warrant modification in significant renal failure

True (azithromycin is primarily metabolised and eliminated in the liver and so no adjustments are necessary in renal disease)

92

Selective use of azithromycin for acne vulgaris and Rosacea may be helpful in some patients who are intolerant to tetracyclines

True

93

Erythromycin is a rare cause of reversible hearing loss at high doses

True (ototoxicity reported at higher doses or in patients with hepatic or renal dysfunction as erythromycin liver metabolism and renal elimination is reduced in these patents leading to accumulation and increased serum levels of the drug)

94

Erythromycin is a a rare cause of skin eruptions and allergic reactions

True

95

Cardiac conduction abnormalities have been associated with macrolide use, and erythromycin carried the greatest risk of QT prolongation and torsades de pointes

True (risk of Cardiotoxicity increased with advanced age, higher dosages, rapid administration, and history of cardiac disease)

96

Clarithromycin may cause a metallic or bitter taste

True (also fixed drug eruption, leukocytoclastic vasculitis and hypersensitivity reactions)

97

Azithromycin has been associated with photosensitivity

True (also irreversible deafness, angioedema, hypersensitivity reactions and contact dermatitis)

98

Macrolide antibiotics (erythromycin, clarithromycin, azithromycin) have been associated with cholestatic hepatitis

True

99

There is increased risk of hypertrophic pyloric stenosis in infants exposed to macrolides through breast feeding mothers as these drugs are secreted into breast milk

True

100

Amiodarone (antiarrhythmic agent) may increase serum levels of erythromycin and clarithromycin (macrolides) through CYP3A4 inhibition

True (besides being a CYP3A4 inhibitor itself, erythromycin and clarithromycin is also subjected to CYP3A4 metabolism)

101

Fluoxetine (SSRI antidepressant) may increase serum levels of erythromycin and clarithromycin (macrolides) through CYP3A4 inhibition

True (besides being a CYP3A4 inhibitor itself, erythromycin and clarithromycin is also subjected to CYP3A4 metabolism)

102

Ketoconazole, itraconazole, fluconazole (azole antifungal agents) may increase serum levels of erythromycin and clarithromycin (macrolides) through CYP3A4 inhibition

True (besides being a CYP3A4 inhibitor itself, erythromycin and clarithromycin is also subjected to CYP3A4 metabolism)

103

Diltiazem and verapamil (calcium channel blockers) may increase serum levels of erythromycin and clarithromycin (macrolides) through CYP3A4 inhibition

True (besides being a CYP3A4 inhibitor itself, erythromycin and clarithromycin is also subjected to CYP3A4 metabolism) -
nifedipine is not a CYP3A4 inhibitor

104

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels many drugs

True (mainly inhibit activity of CYP3A4 and to a lesser extent inhibit activity of CYP1A2)

105

Rifampicin (rifamycin antibacterial agents) may reduce serum levels of erythromycin and clarithromycin (macrolides) through CYP3A4 induction

True (besides being a CYP3A4 inhibitor itself, erythromycin and clarithromycin is also subjected to CYP3A4 metabolism)

106

Carbamazepine, valproate (anticonvulsants) may reduce serum levels of erythromycin and clarithromycin (macrolides) through CYP3A4 induction

True (besides being a CYP3A4 inhibitor itself, erythromycin and clarithromycin is also subjected to CYP3A4 metabolism)

107

Bexarotene (rexinoid type of retinoid) may reduce serum levels of erythromycin and clarithromycin (macrolides) through CYP3A4 induction

True (besides being a CYP3A4 inhibitor itself, erythromycin and clarithromycin is also subjected to CYP3A4 metabolism)

108

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels and potential toxicity of antiarrhythmic agents (amiodarone, flecainide) which are substrates of CYP3A4

True (QT prolongation and torsades de pointes)

109

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels and potential toxicity of warfarin which is a substrate of both CYP3A4 and CYP1A2

True (increased anticoagulant effect and risk of haemorrhage)

110

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels and potential toxicity of anticonvulsants (carbamazepine, valproate) which are substrates of CYP3A4

True

111

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels and potential toxicity of CsA which is a substrate of CYP3A4

True (increased risk of nephrotoxicity, neurotoxicity and hypertension)

112

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels and potential toxicity of Bexarotene which is a substrate of CYP3A4

True (Bexarotene is also a CYP3A4 inducer itself)

113

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels and potential toxicity of statins (Atorvastatin, lovastatin, Simvastatin) which are substrates of CYP3A4

True (increased risk of myopathy, rhabdomyolysis, hepatotoxicity)

114

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels and potential toxicity of theophylline which is a substrate of CYP1A2

True

115

Macrolides (erythromycin and Clarithromycin) inhibit the first pass Cytochrome P450 system in the liver and intestines, leading to decreased metabolic clearance and raised plasma levels and potential toxicity of certain benzodiazepines as these are substrates of CYP3A4

True

116

Ciprofloxacin and moxifloxacin (Fluoroquinolones) oral bioavailability is excellent and minimally affected by food

True (except norfloxacin) - therefore for most cutaneous infections parenteral therapy has no definitive advantage over the PO route

117

Ciprofloxacin and norfloxacin (fluoroquinolones) are mainly excreted renally and patients with significant renal impairment require dosage adjustment

True (except moxifloxacin)

118

Ciprofloxacin (fluoroquinolone) is the treatment of choice against cutaneous anthrax

True

119

Oral fluoroquinolone may be helpful in some cases of gram -Ve folliculitis, including persistent 'hot tub folliculitis' caused by pseudomonas aeruginosa

True (Isotretinoin may be needed for refractory cases and/or recurrences)

120

GI upset such as nausea, vomiting, diarrhoea is the most common adverse reactions associated with fluoroquinolones

True

121

Fluoroquinolones may cause CNS adverse effects I.e. Headaches, dizziness, agitation, sleep disturbances, seizures, psychotic reactions, hallucinations and depression

True (some of the CNS reactions may relate to fluoroquinolone antagonism of the GABA neurotransmitter)

122

Fluoroquinolone may impair cartilage formation based on animal studies, and this is generally avoided in children

True

123

Fluoroquinolone may cause delayed onset tendinitis and tendon rupture

True

124

Fluoroquinolones may cause hypersensitivity reactions with more serious anaphylactoid or anaphylactic reactions reported in Ciprofloxacin use

True

125

Fluoroquinolones may cause photosensitivity

True (evening dosing may minimise phototoxic potential)

126

Fluoroquinolones may cause photo-onycholysis

True

127

Blue-black pigmentation of the legs similar to minocycline dyschromia with demonstration of iron particles within the cytoplasm of dermal macrophages as been reported with perfloxacin fluoroquinolone therapy

True

128

Moxifloxacin fluoroquinolone has been associated with QT prolongation and torsades de pointes

True

129

All fluoroquinolones show decreased bioavailability when administered with calcium, aluminium and magnesium antacids + iron and zinc containing products; with a marked reduction in GI absorption likely due to chelation and the formation of cation-fluoroquinolone complexes that are poorly absorbed

True (patients to take the antibiotic at least 1-2 hours before, and not within hours after the ingestion of the above products)

130

Ciprofloxacin and other fluoroquinolones are CYP1A2 inhibitors

True

131

Fluoroquinolones increase the serum levels and potential toxicity of warfarin (CYP1A2 and CYP3A4 substrate) due to inhibition of CYP1A2

True

132

Fluoroquinolones increase the serum levels and potential toxicity of theophylline (CYP1A2 substrate) due to inhibition of CYP1A2

True

133

Tetracyclines exhibit a wide variety of direct and indirect anti-inflammatory properties that are unrelated to their antibiotic activity

True (acne vulgaris, Rosacea, immunobullous disease, sarcoidosis)

134

Tetracyclines inhibit the production of neutrophil chemoattractants by P. acnes

True (role in acne vulgaris)

135

Tetracyclines inhibit neutrophil migration

True

136

Tetracyclines inhibit granulomatous formation

True (role in sarcoidosis)

137

Alterations of the tetracyclines structure may alter its phototoxic potential, a dose-related phenomenon more commonly associated with doxycycline > tetracycline, and minimally from minocycline

True

138

Tetracycline is short acting and doxycycline + minocycline are long acting tetracyclines

True

139

The greatest prevalence of P. Acnes resistance is with tetracycline (as compared to doxycycline and minocycline)

True

140

Subantimicrobial dosing of doxycycline does not induce antibiotic-resistant bacterial strains

True

141

Tetracyclines are lipophilic allowing significant drug levels in the pilosebaceous unit, reaching high concentrations in skin and nails

True (order of lipophilicity is minocycline > doxycycline > tetracycline)

142

Tetracyclines can cross the blood-brain barrier

True (may cause pseudotumour cerebri)

143

Doxycycline is well absorbed regardless of food intake though a meal reduces GI absorption by 20%

True

144

Tetracycline is better absorbed in the fasting state

True

145

Minocycline immediate release formulation is well absorbed regardless of food intake

True (this is in contrast to the extended release formulation, which is better absorbed in a fasting state)

146

Dairy products (contain metallic cations such as calcium and magnesium), vitamin/mineral supplements antacids and antidiarrhoeal products can markedly reduce the GI absorption of tetracyclines through chelation of these drugs in the stomach

True (calcium, magnesium, aluminium, iron, zinc) - important to question patients about OTC products for indigestion, diarrhoea, or stomach upset which may reduce levels of the tetracyclines

147

GI side effects such as nausea, abdominal discomfort and 'pill oesophagitis' are more common with doxycycline

True (enteric coating of doxycycline has been shown to reduce GI adverse effects) - symptoms develop typically in the first few days, presenting most often as odynophagia, dysphagia, and retrosternal pain; and is usually avoidable with proper patient education to ingest with a large volume of water and not to take before reclining

148

Vestibular side effects are reduced with slower/extended release minocycline formulations as this side effect relates to the serum drug levels

True

149

Doxycycline is excreted primarily in the GI tract in bile and is acceptable for use in patients with renal failure, but caution is warranted in patients with severe liver disease

True (doxycycline not contraindicated in renal failure, unlike the other minocycline and tetracycline which are renally excreted and renal failure prolongs their half-life)

150

Doxycycline and minocycline have 2 main advantages over tetracycline for chronic inflammatory facial dermatoses (acne vulgaris, Rosacea, perioral dermatitis) - (1) less frequent dosing, (2) lower prevalence of less sensitive P. acnes strains

True

151

PO tetracyclines usually requires at least 3 weeks before initial visible improvement of chronic inflammatory facial dermatoses (acne vulgaris, Rosacea, perioral dermatitis) with maximum benefit between 3 and 6 months

True

152

Typically about 50% of patients with chronic inflammatory facial dermatoses (acne vulgaris, Rosacea, perioral dermatitis) relapse within 8 weeks of cessation of PO tetracyclines, often requiring additional courses

True

153

Doxycycline (and to a lesser extent tetracycline) is used in the treatment of papulopustular Rosacea, ocular Rosacea and perioral dermatitis (Rosacea variant), but does not improve erythematotelengiectatic Rosacea

True (reduces inflammatory lesions, perilesional erythema, and symptoms of stinging, burning, pruritus)

154

Pertinent to women with history of antibiotic-induced vaginal candidiasis, low dose doxycycline used for Rosacea is devoid of antibiotic selection pressure and is not associated with vaginal candidiasis in actively treated women

True

155

Tetracyclines (especially doxycycline) have been used most often in combination with nicotinamide for the treatment of immunobullous diseases such as bullous pemphigoid, linear IgA bullous dermatosis, Pemphigus vulgaris, Pemphigus foliaceus, benign familial Pemphigus/Hailey-Hailey disease, and cicatricial pemphigoid/mucous membrane pemphigoid

True

156

Tetracyclines may be useful in granulomatous diseases i.e. Doxycycline in cutaneous sarcoidosis, minocycline in silicone granuloma

True

157

Cetuximab-related acneiform cutaneous eruption responds to PO Minocycline and topical Tazarotene

True

158

Doxycycline and tetracycline is recommended in the treatment of syphilis in patients allergic to penicillin

True

159

Tetracyclines (most commonly doxycycline) can cause GI adverse effects including nausea, vomiting and abdominal discomfort

True

160

Even though diarrhoea is occasionally reported with tetracyclines, antibiotic-associated colitis due to C. Diff infection is rare

True

161

The presence of hiatus hernia may be a risk factor for 'pill oesophagitis' with doxycycline

True (pre-existing GORD is not a definitive risk factor)

162

Drug-induced hepatitis and pancreatitis are very uncommonly observed with various tetracyclines

True

163

Acute vestibular side effects presenting mainly as dizziness or vertigo (possibly with nausea and vomiting) are most common with minocycline immediate release formulations

True (typically occurs after the first dose or within a few days, are more common in women especially those of low body weight)

164

If acute vestibular side effects most commonly associated with minocycline immediate release formulation do not occur in the first few weeks of treatment, then they are not likely to occur later

True

165

Benign intracranial hypertension (pseudotumour cerebri) is an uncommon idiopathic reaction to the tetracyclines and persistence of this disorder can lead to severe loss of vision which may be permanent

True (headache and visual disturbances accompanied by nausea and/or vomiting)

166

Cutaneous phototoxicity and photo-onycholysis have been mainly reported with doxycycline use, mainly provoked by UVA but UVB may have a synergistic role

True (in contrast to minocycline which has been shown to exhibit negligible or absent phototoxicity potential) - prudent to educate patients on optimal photoprotection and avoidance of intentional natural and/or artificial UVA or UVB tanning

167

Minocycline has been shown to exhibit negligible or absent phototoxicity potential

True

168

Hyperpigmentation of skin, nailbeds, teeth, bone and mucous membranes including oral mucosa and sclera has been reported mainly with minocycline immediate release formulation, particularly with long term acne therapy

True (after cumulative dose of >70 g) - the formation of pigmentation was at sites of prior inflammation, trauma, areas of scar formation

169

Tetracycline has been associated with discolouration of adult teeth

True

170

Doxycycline has been associated with nail discolouration in paediatric patients, with features clinically, histologically, and ultrastructurally resembling those of long term high dose minocycline

True

171

Tetracyclines are contraindicated in children less than 9 years of age owing to yellow staining of teeth and possibly other adverse effects on the development of bones and teeth

True (especially tetracycline)

172

Tetracycline can precipitate vaginal candidiasis

True

173

Long term Tetracycline can precipitate gram -Ve acne or folliculitis

True

174

Tetracyclines may uncommonly cause hypersensitivity reactions including urticaria, fixed-drug eruption and drug-induced Sweets syndrome

True

175

Minocycline has been associated with serum sickness-like reactions especially in HIV patients and black African ethnicity

True (typically occur during first 1-2 months)

176

Doxycycline and minocycline have caused SJS

True

177

Minocycline has exclusively caused delayed autoimmune adverse reactions (autoimmune hepatitis), systemic lupus-like reactions and ANCA vasculitis

True (delayed for months to years)

178

Minocycline is the most common of the tetracyclines to cause drug hypersensitivity syndrome or drug reaction with eosinophilic and systemic symptoms (DRESS), with hepatitis being the most common component of the multisystem involvement

True

179

A lupus-like syndrome and other autoimmune adverse reactions appear to be unique to minocycline

True (sometimes with neutropenia)

180

Despite the propensity of minocycline causing a lupus-like syndrome, the emergence of a positive ANA during therapy does not equate to autoimmune disease as most patients with newly formed autoantibodies do not develop clinical disease

True

181

Minocycline may cause cutaneous polyarteritis nodosa (PAN) and vasculitis after 2-3 years of long term use

True

182

Minocycline may cause immune thrombocytopenia, presenting as Schamberg disease

True

183

Minocycline may cause neutropenia as a component of lupus-like syndrome

True

184

Tetracyclines at any time during pregnancy for inflammatory disorders is not recommended

True (and especially contraindicated in the second and third trimesters of pregnancy due to synthesis of fetal teeth and bones, congenital defects, maternal hepatotoxicity)

185

Tetracyclines ought to be avoided during lactation unless the benefits clearly outweigh the risks

True

186

Alcohol (chronic intake) increases doxycycline metabolism as alcohol is a Cytochrome P450 enzyme inducer

True (doxycycline metabolised and excreted in liver/bile)

187

Rifampicin (antiTB antibiotic) may reduce the levels of doxycycline due to increased metabolism by CYP3A4 induction

True (doxycycline is a substrate of CYP3A4)

188

Phenytoin, carbamazepine (anti-convulsants) may reduce the levels of doxycycline due to increased metabolism by CYP3A4 induction

True (doxycycline is a substrate of CYP3A4)

189

Quinalapril (ACE-inhibitor with high magnesium content) may reduce the GI absorption of tetracyclines due to chelation

True

190

Antacids (contain calcium, magnesium, aluminium) reduce the GI absorption of tetracyclines due to chelation

True

191

Cimetidine (H2 antihistamine) reduce the GI absorption of tetracyclines due to pH-dependant inhibition of drug dissolution

True

192

Other chelating drugs including iron, zinc, bismuth salts reduce the GI absorption of tetracyclines due to chelation

True

193

Bile acid sequestrants (cholestyramine) reduce the GI absorption of tetracyclines

True

194

Tetracyclines may increase the serum levels and potential toxicity of warfarin due to tetracyclines-induced changes in gut flora affecting enterohepatic recirculation of warfarin

True

195

Tetracyclines may increase the serum levels and potential toxicity theophylline (xanthine oxidase inhibitor)

True

196

Tetracyclines may increase the serum levels and potential toxicity of digoxin

True

197

Tetracyclines may reduce the serum levels and efficacy of hormonal contraceptives as they theoretically inhibit enterohepatic recirculation of Oestrogens

True

198

Tetracyclines may potentially increase the photosensitivity of St John's wort

True (doxycycline and tetracycline may cause photosensitivity in their own right)

199

Tetracyclines may potentially increase the photosensitivity of porphyrins I.e. ALA used in PDT

True (doxycycline and tetracycline may cause photosensitivity in their own right)

200

Tetracyclines may potentially increase the photosensitivity of psoralens (used in PUVA therapy)

True (doxycycline and tetracycline may cause photosensitivity in their own right)

201

Tetracyclines may potentially increase the photosensitivity of retinoids (reduce stratum corneum thickness)

True (doxycycline and tetracycline may cause photosensitivity in their own right)

202

Concomitant use of tetracyclines and oral retinoids may increase the risk of benign intracranial hypertension (pseudotumour cerebri)

True (both drug classes independently cause this adverse effect)

203

When used for atypical mycobacterial infections or leprosy, rifampicin is administered in combination with other anti-TB drugs and can be used over several months

True

204

Rifampicin has been used in combination with either Clindamycin or Bactrim (trimethoprim-sulfamethoxazole) when treating CA-MRSA

True (resistance of staph aureus strains develops rapidly when rifampicin monotherapy is used)

205

GI absorption of rifampicin may be reduced by approximately 1/3 when ingested with food

True

206

Rifampicin induces its own liver metabolism

True (Cytochrome P450 inducer)

207

30% of rifampicin is excreted in the kidneys

True

208

Although rifampicin crosses the placenta, it is not a particular teratogen although if used in the last few weeks of pregnancy can cause haemorrhagic disease of the newborn and mother which requires prophylactic vitamin K

True

209

Rifampicin is a potent inducer of multiple Cytochrome P450 Isoforms including CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4

True

210

Rifampicin is intensely red in colour and highly lipophilic with widespread body distribution and causes harmless orange-red discolouration of liquid body excretions (urine, sweat, tears, breast milk) a few hours after ingestion of a dose and light staining of fabric and permanent staining of soft contact lenses sometimes observed

True

211

Rifampicin has been associated with CNS symptoms including headache, drowsiness, ataxia, dizziness, inability to concentrate and fatigue

True

212

Rifampicin has been associated with GI effects including epigastric distress, nausea, vomiting and diarrhoea

True

213

C. Diff antibiotic-associated colitis has been rarely reported with Rifampicin use

True

214

Rifampicin used intermittently and in high doses has rarely cause immunogenicity effects leading to the formation of rifampicin-mediated antibodies

True (minor cutaneous, GI, and influenza-like syndromes or more severe thrombocytopenia, haemolytic anaemia, acute renal failure and immunobullous diseases)

215

Rifampicin may be associated with asymptomatic changes in LFTs especially transaminases and possibly hyperbilirubinaemia, although symptomatic hepatotoxicity is more likely when rifampicin is used in combination with isoniazid

True (dosage reduction may be needed in patients with severe hepatic impairment)

216

Use of rifampicin in patients with impaired liver function warrants careful clinical assessment and lab monitoring of LFT

True (rifampicin induces its own metabolism in the liver)

217

Patients on rifampicin are at increased risk of developing DVT

True

218

Rifampicin may exacerbate porphyria due to induction of the enzyme delta-aminolevulenic acid synthetase and should be avoided in this patient population

True

219

Rifampicin may cause pulmonary fibrosis

True

220

Rifampicin may cause ocular toxicity

True

221

Rifampicin causes increased clearance of oral contraceptives leading to decreased efficacy and unintended pregnancy

True (CYP inducer causing increased drug clearance)

222

Rifampicin causes decreased anticoagulant effects of warfarin leading to reduced ability to achieve therapeutic INR levels

True (CYP inducer causing increased drug clearance)

223

Rifampicin causes reduced antifungal activity of azole antifungal agents leading to persistence of infection

True (CYP inducer causing increased drug clearance)

224

Rifampicin causes decreased serum levels of several HMG CoA-reductase inhibitors (CYP3A4 substrates Simvastatin, lovastatin, Atorvastatin) leading to loss of cholesterol control

True (CYP inducer causing increased drug clearance)

225

Rifampicin causes reduction of CsA or tacrolimus serum levels leading to decreased immunosuppressive effect and therapeutic failure

True (CYP inducer causing increased drug clearance)

226

Concomitant antacid ingestion may reduce GI absorption of rifampicin

True (rifampicin given 1 hour before antacid intake)

227

The half-lives of TMP-SMX (Bactrim) may be prolonged in the presence of marked renal insufficiency due to renal excretion

True (dosage adjustment is warranted for patients with renal insufficiency)

228

TMP-SMX (Bactrim) is distributed into breast milk and cross the placenta

True

229

TMP-SMX (Bactrim) is partially bio-transformed via hepatic metabolism

True

230

30-60% of TMP and 20-40% of SMX in Bactrim is renally excreted

True

231

GI adverse effects can be associated with TMP-SMX (Bactrim) including nausea, vomiting and loss of appetite

True

232

CNS adverse effects can be associated with TMP-SMX (Bactrim) including cephalgia, dizziness and tinnitus

True

233

Antibiotic-associated colitis due to C. Diff has been reported with TMP-SMX (Bactrim)

True

234

TMX-SMX (Bactrim)-induced cutaneous eruptions including exanthematous and urticarial eruptions and/or pruritus may be seen in 4-5% of healthy patients and approximately 15% of HIV-infected patients, usually manifesting within 1-2 weeks after starting therapy

True

235

Sulfonamide-related drug hypersensitivity syndrome, SJS, TEN and haematologic reactions (agranulocytosis) are adverse effects of greatest concern with TMP-SMX

True

236

In most cases, drug hypersensitivity syndrome or SJS/TEN manifest within the first 2-6 weeks after starting TMP-SMX (Bactrim)

True (patients should be told to discontinue treatment if they develop flu-like symptoms, arthralgias, or painful skin)

237

TMP-SMX (Bactrim) should be avoided in patients with first-degree relatives who have experienced drug hypersensitivity syndrome or SJS/TEN associated with sulfonamide use and in those that have a prior sulfonamide allergy

True

238

Uncommonly haematologic reactions associated with TMP-SMX (Bactrim) are thrombocytopenia, neutropenia, hypopothrombinaemia, aplastic anaemia/pancytopenia, and pure red cell aplasia

True

239

TMP-SMX (Bactrim) may cause haemolytic anaemia in patients with G6PD deficiency

True (sulfonamide adverse effect)

240

TMP-SMX (Bactrim) should be used very cautiously in patients with a possible folate deficiency or in those with pre-existing megaloblastosis as it has been suggested that megaloblastosis may predispose patients to some haematopoetic adverse effects with exposure to TMP-SMX (Bactrim)

True

241

TMP-SMX (Bactrim) may also cause pustular skin eruptions

True

242

TMP-SMX (Bactrim) may also cause drug-induced Sweet's syndrome

True

243

TMP-SMX (Bactrim) may cause nail changes including Beau's lines, paronychia, partial leukonychia, and photo-onycholysis

True

244

Breastfeeding should be avoided in patients taking TMP-SMX (Bactrim) as premature infants and those with hyperbilirubinaemia should not be exposed to TMP-SMX (Bactrim) via breast milk as SMX competes with bilirubin binding to plasma albumin

True

245

TMP-SMX (Bactrim) increases dapsone levels warranting closer monitoring of dapsone toxicity (myelosuppression and methaemoglobinaemia)

True

246

TMP-SMX (Bactrim) increases the risk of blood dyscrasias in patients on MTX

True

247

Reversible nephrotoxicity has been reported in renal transplant patients concomitantly on TMP-SMX (Bactrim) and CsA and avoidance of co-administration if clinically feasible is preferred

True

248

Resistance to Clindamycin generally can confer resistance to macrolides (erythromycin)

True

249

Clindamycin is well absorbed orally independent of food with wide tissue distribution

True

250

Clindamycin is highly protein bound, is metabolised predominantly in the liver and excreted in the urine as inactive metabolites

True (the plasma half-life is raised slightly with severe renal or hepatic failure) - dosage adjustment is necessary in liver failure as protein synthesis and binding is affected, although no dosage adjustment is needed in renal failure patients

251

Concern regarding the risk of antibiotic-associated colitis has markedly limited Clindamycin use in acne vulgaris patients

True (though still used in cellulitis, folliculitis, furunculosis, carbuncles, impetigo, ecthyma and hidradenitis suppurativa)

252

Other GI adverse effects associated with Clindamycin include nausea, vomiting and elevated transaminases

True

253

Clindamycin may rarely cause bone marrow suppression

True

254

Clindamycin may rarely cause renal impairment

True

255

Clindamycin has been associated with exanthematous or urticarial eruptions, anaphylaxis, erythema multiforme, SJS-type reaction with polyarthritis

True

256

Clindamycin is not teratogenic

True

257

Clindamycin has been shown to have neuromuscular blocking properties that may enhance the effect of other neuromuscular agents

True

258

The usual adult dose of Clindamycin is 150mg - 300mg BD although hidradenitis suppurativa may require 300mg TDS

True

259

Antibiotics eliminated through the biliary system include:
(1) Piperacillin (Penicillin)
(2) Nafcillin (Penicillin)
(3) Oxacillin (Penicillin)
(4) Moxifloxacin (Fluoroquinolone)
(5) Azithromycin (Macrolide)
(6) Doxycycline (Tetracyclines)

True (all other antibiotics are eliminated through the kidneys)

260

The following antibiotic groups are susceptible to chelation in the GI tract (causing reduced absorption and bioavailability) when concomitantly administered with calcium, magnesium, zinc, iron, bismuth salts:
(1) Fluoroquinolones (Ciprofloxacin, Moxifloxacin, Norfloxacin)
(2)Tetracyclines (Tetracycline, Doxycycline, Minocycline)

True

261

Dose reduction should be considered for the following antibiotics in the setting of renal insufficiency:
(1) Penicillins
(2) Cephalosporins
(3) Vancomycin
(4) Erythromycin and Clarithromycin (Macrolides)
(5) Ciprofloxacin and Norfloxacin (Fluoroquinolones)
(6) Tetracycline and Minocycline (Tetracyclines) - use with caution
(7) Bactrim/TMP-SMX

True (renally excreted)
The following are safe in renal impairment due to bile excretion:
Azithromycin (Macrolide)
Moxifloxacin (Fluoroquinolone)
Doxycycline (Tetracyclines)
N.B. Even though Clindamycin is really excreted, no dosage adjustment is needed in renal failure patients

262

Dose reduction should be considered for the following antibiotics in the setting of liver disease:
(1) Rifampicin - risk of toxicity as it is an inducer of its own liver metabolism
(2) Clindamycin - increase serum free drug in liver disease as it is highly plasma protein bound and liver disease affects plasma protein synthesis

True

263

The following antibiotics are nephrotoxic/may cause renal impairment:
(1) Vancomycin (particularly when co-administered with gentamicin)
(2) Gentamicin
(3) Clindamycin
(4) Bactrim/TMP-SMX (when co-administered with CsA)

True

264

The following antibiotics are best absorbed from an empty stomach:
(1) Cephalexin
(2) Erythromycin (non-enteric coated)
(3) Extended release Minocycline (but not the immediate release formulation)
(4) Rifampicin (also sensitive to antacids which reduces its absorption)

True
NB. In contrast, Cefuroxime bioavailability is increased with food intake