ANTIBIOTICS Flashcards
(176 cards)
1
Q
what two types of antibiotics inhibit cell wall synthesis?
A
beta lactams= penicillin, cephalosporin, carbapenams and monobactams
glycopeptides= vancomycin and teicolpanin
2
Q
what 4 types of antibiotics are protein synthesis inhibitors?
A
aminoglycosides= gentamicin
macrolides= erythromycin, clarithromycin and azithromycin
tetracyclines= doxy
oxazolidinones
3
Q
what 3 types of antibiotic are DNA synthesis inhibitors?
A
trimethoprim/sulphonamides
quinolone= nalidixic acid
fluroquinolones= ciprofloxacin, levofloxcain
4
Q
what type of antibiotic is an RNA synthesis inhibitor?
A
rifampicin
5
Q
give 2 types of antibiotics that are plasma membrane agents
A
daptomycin
polymycin
6
Q
give 2 other types of antibiotics
A
nitrofurantoin
metronidazole (anaerobic)
7
Q
what antibiotic group are penicillins?
A
beta lactams that contain B lactam ring= gives antimicrobial properties
8
Q
are penicillins broad or narrow spectrum?
A
broad
9
Q
how do penicillins work?
A
It inhibits enzyme cell wall synthesis by - preventing cross linking between peptidoglycan chains. Causing uncontrolled entry of water into bacteria causes cell swelling, lysis and death
10
Q
what type of bacteria are targeted by penicillins?
A
gram +ve and -ve
11
Q
when is the only instance that penicillins are taken well into the CNS?
A
inflammation of meninges
12
Q
what other drugs should be used in caution if there is hypersensitivity to penicillin?
A
cephalosporins
other b lactams
13
Q
how can bacteria inactive penicillins?
A
produce beta lactamases
14
Q
name a serious GI side effect of penicillins
A
antibiotic associated colitis
15
Q
how can penicillins interact with the COCP?
A
reduce effectveness
16
Q
how can probenecid interact with penicillins?
A
reduce excretion - anti gout drug
17
Q
give an example of a first generation cephalosporin
A
cephradine
18
Q
give an example of a second generation cephalosporin
A
cefuroxime
19
Q
give an example of a 3rd generation cephalosporin
A
cefotaxime
ceftazidime
ceftiaxone
20
Q
how do cephalosporins work?
A
same as penicillin
cell wall synthesis inhibitor (prevent peptidoglycan cross linking)
21
Q
which type of bacteria are second generation cephalosporins more active against?
A
They are less susceptible to B lactamase and effective against gram +ve
22
Q
which type of bacteria are third generation cephalosporins more active against?
A
gram -ve
23
Q
what cephalosporin is used in pneumocci and H.infleunzae meningitis?
A
cefotaxime
24
Q
what kind of spectrum do cephalosporins have? What type of infections it is used for?
A
very broad
Second and third line treatment for urinary tract infection and respiratory tract infections
25
what respiratory condition can reduce the effectiveness of cephalosporins?
COPD
26
what drug can reduce excretion of cephalosporins?
probenecid
27
how do cephalosporins interact with warfarin?
increase anticoagulant effect
28
give an example of a glycopeptide
vancomycin
| teicoplanin
29
how do glycopeptides work?
cell wall synthesis inhibitors
| bind to cell wall and competitively inhibit cross linking
30
what types of bacteria are glycopeptides effective against?
gram +ve as they cannot degrade the cell wall of grame -ve
aerobic &anaerobic
MRSA TOO!
31
which glycopeptides would be used in endocarditis and c.diff, and the other in endocarditis, cellulitis peritonitis and diabetic foot infection?
a) vancomycin
b) teicoplanin
a) endocarditis, c. diff = vancomycin
| b) endocarditis peritonitis, cellulitis and diabetic foot infection = teicoplanin
32
why should glycopeptides be used IV in systemic infections?
Poorly absorbed orally in systemic infections
33
glycopeptide should be avoided in the elderly in which circumstance?
history of deafness
| Renal impairment
34
IV Glycopeptides can lead to which blood disorder?
neutropenia and thrombocytopenia
35
Name a serious side effect of giving infusing IV glycopeptide rapidly
Red man syndrome = generalised erythema +/- hypotension and bronchospasm
36
Name an ENT side effect of IV glycopeptides?
Ototoxicity leading to tinnitus and deafness
37
give an example of a tetracycline
doxycycline
38
how do tetracyclines work
Bacterial protein synthesis inhibitors
| Binds to ribosome 30s sub unit specific to bacteria and prevents RNA translation
39
what is the spectrum of tetracyclines?
broad spectrum
40
Are tetracyclines bactericidal or bacteriostatic?
bacteriostatic
41
name 2 systems that tetracyclines are used to treat infections in
```
Respiratory= LRTI including infective exacerbation of COPD (h.influenzae), pneumonia and atypical pneumonia
Genital= chlamydia and pelvic inflammatory disorders
```
42
name 2 skin conditions that tetracyclines are used in
acne rosacea
| acne vulgaris
43
Name an infectious disease that tetracyclines are used to treat
Typhoid, anthrax, malaria and lyme
44
why shouldn't tetracyclines be used in myasthenia gravis patients?
can increase muscle weakness
45
why shouldn't tetracyclines be used in patients with SLE?
can exacerbate
46
why shouldn't tetracyclines be used in children under 12?
deposits in growing bone and teeth - staining and hypoplasia
47
why shouldn't tetracyclines be used in pregnancy and breastfeeding?
deposits in growing bone and teeth - staining and hypoplasia
48
what severe acute disease can be triggered by tetracyclines?
acute porphyria
49
name 2 neurological side effects of tetracyclines
photosensitivity
| benign intracranial hypertension causing headache and blurred vision
50
how do tetracyclines interact with anticonvulsants?
increase doxycycline metabolism
51
how do tetracycline interact with methotrexate?
increase risk of toxicity
52
give an example of an aminoglycoside
gentamicin
streptomycin
amikacin
Tobramycin
53
how do aminoglycosides work?
protein synthesis inhibitors
They bind to ribosomal 30s subunit
They are bactericidal
54
What is infections are aminoglycosides generally used against?
1) Severe sepsis even when organism is unknown
2) pyelonephritis and complicated urinary tract infections
3) Biliary and other intra abdominal sepsis infections
55
why are aminoglycosides often used with beta lactams or metronidazole?
Lack activity against streptococci or anaerobes and therefore used in combination when the organism is unknown
56
what kind of bacteria are aminoglycosides effective against?
Mainly gram negative aerobic bacteria
Also pseudomonas aeruginosa
Some gram +ve (e.g staph)
57
which of these aminoglycosides would you use against p aeruginosa, then m tuberculosis
a) gentamicin
b) streptomycin
a) gent = p aeruginosa
| b) strep = m tuberculosis
58
why should't aminoglycosides be used in myasthenia gravis?
impair neuromuscular junction transmission
59
why shouldn't aminoglycosides be used in 2nd or 3rd trimester of pregnancy?
Cross the placenta causing damage to the auditory and vestibular nerve
Streptomycin greatest risk
60
What renal side effect can you get with aminoglycosides?
Nephrotoxicity= reduced urine output and increase serum creatinine levels
61
Give a ENT side effect of aminoglycosides
ototoxicity= tinnitus and deafness
62
Aminoglycoside in combination with what drugs can potentiate nephrotoxicity?
```
Platinum
Chemotherapy
Cyclosporine
Vancomycin
Cephalosporin
```
63
Aminoglycoside in combination with what drugs can potentiate ototoxicity?
Loop diuretics and vancomycin
64
why shouldn't aminoglycosides be used for more than 7 days?
toxicity risk
65
How is the dose of aminoglycoside calculated and how is it administrated?
Based on weight and renal function
| IV
66
give an example of a macrolid
erythromycin
clarithromycin
azithromycin
67
Are macrolides bactericidal or bacteriostatic?
bacteriostatic
68
how do macrolides work?
protein synthesis inhibitors
They bind to ribosomal 50s subunit preventing translocation occurring
Inhibit protein elongation by blocking exit tunnel of ribosome
69
when are macrolides used?
Alternative to penicillin
Respiratory infection
Skin and soft tissue infection
Serious pneumonia with penicillin and atypical pneumonia (Legionella pneumophila and Mycoplasma pneumoniae)
Non-gonococcal urethritis= erythromycin
Uncomplicated chlamydia infection
70
Macrolides should be used with caution for patients with what ECG abnormality?
prolonged QT interval and arrhythmias
71
how should dosing change for a patient with a reduced eGFR?
half dose
72
What are the common abdominal side effects of oral macrolides?
Nausea and vomiting
Abdominal pain
Diarrohea
73
What is a cardiac side effect of macrolides?
QT interval prolonged which can lead to arrhythmias
74
What action does clarithromycin and erythromycin have on cytochrome p450?
Inhibit cytochrome p450
75
give an example of a fluoroquinolone
ciprofloxacin
Levofloxacin
Mexifloxacin
76
What type of organisms are quinolones most effective against?
Aerobic gram -ve bacteria
77
are fluoroquinolones bactericidal or bacteriostatic?
bactericidal
78
Are quinolones effective against gram +ve?
Ciprofloxacin has limited effect against +ve
| Levofloxacin and mexifloxacin increased activity against +ve and therefore can be used in LRTI
79
what antibiotic might you use to treat campylobacter and neusseria?
fluroquinolones
80
how do fluoroquinolones work?
Inhibit DNA replication by interacting with bacteria specific enzyme that is invovled with DNA replication
81
which type of fluoroquinolone would be better to treat CAP and why?
a) levofloxacin
b) ciprofloxacin
a) levofloxacin (greater against pneumococcal activity)
82
What is quinolones used to treat?
```
UTI and acute pyelenophritis (cipro)
Severe GI tract infections= e.g. shigella and campylobacter
LRTI= Levofloxacin and mexifloxacin
Joint and bone infection
Gonorrhea and septicaemia
```
83
what systemic infection are fluoroquinolones used to treat?
septicaemia
84
why shouldn't fluoroquinolones be taken by patients with epilepsy or previous history of seizures?
lowers seizure threshold
85
why shouldn't fluoroquinolones be used with cyclosporin?
increases nephrotoxicity
86
What is the effect of quinolones on cytochrome p450?
Inhibit the enzyme
87
why shouldn't fluoroquinolones be used with
a) warfarin
b) theophylline?
a) increases anticoagulation
| b) increase risk of convulsion and toxicity
88
What organisms are trimethoprim active against?
Broad spectrum Gram +ve and Gram -ve particullarly enterobacteria
89
how does trimethoprim work?
inhibit DNA synthesis by inhibiting folate synthesis (folic acid essential for making purines).
Leads to bacteriostatic
90
How is Co-trimoxazole made and what is it used for?
Trimethoprim and sulfamethoxazole (sulfonamide)
Used to treat pneumocystis pneumonia in immunosuppressed patients.
Also treat acute exacerbations of chronic bronchitis, UTI and otitis media in children = if their is bacterial sensitivity
Travellers diarrohea
91
when is trimethoprim normally used?
First line for UTI
| Also used for respiratory tract infections, shigellosis, invasive salmonella infection
92
why shouldn't trimethoprim be used in 1st trimester of pregnancy?
teratogenic causing cardiovascular defect and oral cleft due to folate antagonist
93
which blood disorders contraindicate use of trimethoprim?
anaemia
| thrombocytopenia
94
Name an immunological side effect of trimethoprim
bone marrow suppression
95
give a severe two severe derm side effects of trimethoprim and especially co-trimoxazole
toxic epidermal necrolysis (TEN) and Steven’s Johnson Syndrome
96
why shouldn't trimethoprim be used with cyclosporin?
increase nephrotoxicity
97
why shouldn't trimethoprim be used with methotrexate (folate antagonist) and phenytoin (^ folate metabolism)?
Increases the risk of adverse haematological effects such as bone marrow suppression
98
give an example of an anaerobic antimicrobial
metronidazole and tinidazole
99
how does metronidazole work?
Passive diffusion into the anaerobic bacteria where it is reduced into free radical.
It damages the DNA synthesis causing DNA degradation and cell death
Bactericidal
100
What is the spectrum of activity for metronidazole?
Anaerobic bacteria and protozoa
101
What infections are metronidazole used to treat?
1) Abx assoicated collitis caused by C.diff ( anaerobic)
2) Oral infections including dental abscess and aspirated pneumonia caused by -VE anarebes
3) Surgical and gynaecological infections from -ve anaerobes from the colon
4) H.pylori eradication with PPI and clarithromycin
5) protozoa infections
102
what physiological state is metronidazole contraindicated in?
pregnancy, breastfeeding
103
What can high doses of prolonged treatment of metronidazole cause?
Peripheral and optic neuropathy, sieuzures and encalopathy
104
why shouldn't metronidazole be taken with alcohol?
It inhibits the excretion of alcohol leading to symptoms of flushing, nausea and vomiting and headache
105
why shouldn't metronidazole be used with phenytoin?
Causes phentyoin toxicity and can cause impaired cerebellar function
106
What effect does metronidazole have on P450?
It is metabolised by p450 and inhibits the enzyme
107
How does nitrofurantoin work?
It is metabolised and reduced by bacteria using nitrofuran reductase.
Forming the active metabolite that damages the bacterial DNA and causes cell death.
108
What two organisms is nitrofurantoin effective against?
Gram -ve E.coli and Gram +ve Staphylococcus saprophyticus. Two most common causes of UTI
109
when is nitrofurantoin mainly used?
Lower UTI = acute cystitis
110
What side effect does nitrofurantoin have on urine?
Cause it to go dark yellow or brown
111
when in the day should nitrofurantoin be taken?
With food or milk
112
what organ impairments contraindicate use of nitrofurantoin?
renal
| hepatic
113
why is nitrofurantoin contraindicated in pregnancy and neonates?
increases risk of haemolytic anaemia
114
why is nitrofurantoin contraindicated for use with magnesium-containing antacids?
reduce absorption
115
What is the potential side effect of prolonged used for nitrofurantoin?
Chronic pulmonary reaction (fibrosis), hepatitis and peripheral neuropathy
116
What are the 4 different types of penicillin?
| Give example for each
Broad spectrum penicillin = Co amoxiclav and amoxicillin
Benzylpenicillin
Antipseudomonal penicillin’s= Piperacillin with tazobactam
Penicillinase resistant penicillin = Flucloxacillin
117
Impairment of what organ would be contradictory to give penicillin?
Renal impairment
118
What is the side effect of high doses of penicillin or when given to patient with renal impairment ?
- Central nervous system toxicity (including convulsions and coma)
119
what is the interaction between penicillin and methotrexate?
- Penicillins reduce renal excretion of methotrexate, increasing the risk of toxicity.
120
Are cephalosporins and carbapenems more or less resistant to beta lactamase produced by bacteria?
More resistant to beta lactemase due to fusion of their beta lactam rings
121
What antibiotics are linked to the development of C.difficile?
Cephalosporins
Ciprofloxacin (and other quinolones)
Clindamycin
Co-amoxiclav
122
IV carbapenems and cephalosporins are used in what situations?
To tackle very severe and complicated infections caused by antibiotic resistant organisms
123
What effect does cephalosporin have on aminoglycoside?
Increase the nephrotoxicity effects of aminoglycoside
124
What is the effect of cephalosporin on valproate?
It reduces the plasma level and efficancy of valproate
125
What route is vancomycin given for abx associated colitis caused by c.diff?
Oral
126
What renal side effect is caused by IV glycopeptide?
Nephrotoxicity ( less in teicoplanin)
127
What is the most common side effect of IV glycopeptide?
Thrombophlebitis at sight of IV
128
Vancomycin Interaction with what drugs increases the risk of ototoxicity and/or nephrotoxicity?
Aminoglycoside
Cyclosporin
Loop diuretics
129
What are the 2 general uses of penicllin?
LRTI
| Urinary tract infection
130
What is broad spectrum penicillin used for?
Empirical treatment for pneumonia either gram +ve (Pneumoccocus pneumonia) or Gram -ve (H.influenzae)
and Urinary tract infection ( caused by E.coli)
Also in combination therapy for H pyolri peptic ulcer disease
131
What is Co-amoxiclav?
Amoxicillin and clavulanic acid
132
What is the benefit or Co-amoxiclav over amoxicillin?
Great range of activity
133
What combination therapy is Co-amoxiclav used in?
Hospital acquired infections and intra abdominal sepsis
134
What does Strep pneumonia and E.coli produce to be resistant to broad spectrum penicillin?
Penicillinase
135
What is the range of use of benzylpenicillin?
Streptococcal infections= Tonsillitis, pneumonia and endocarditis
Clostridium infections= tetanus
Meningococcal infections = Meningitis and septicaemia
136
Benzylpenicillin is given for skin and soft tissue infection in what situations and in combination with what drug?
In severe infections and combination with flucloxacillin
137
What is benzylpenicillin limitation?
It is inactivated by B lactamase
138
What is tazocin?
Piperacillin with tazobactam
139
What bacteria is tazocin specifically used against?
pseudomonal infections
140
Tazocin are preserved for use in what situations?
Severe infection with a range of pathogens
Hospital acquired infection such as HAP
Patient is immunocompromised (neutropenic)
141
What are the infections in which tazocin are used for?
HAP
Complicated Urinary tract infection
Intraabdominal sepsis
Complicated Skin and soft tissue infection
142
What is Flucloxacillin specifically used for?
Penicillin resistant staphylococci infection
143
Why is Flucloxacillin used for staphylococci infections instead of benzylpenicillin?
Staphylococci produce penicillinase which is resistant to benzylpenicillin
144
What infections are flucloxacillin commonly used in?
Impetigo and cellulitis
Osteomyelitis and septic arthritis
Endocarditis
145
What % of patients have a penicillin allergy?
1-10%
146
What is the common presentation of penicillin allergy?
Get a skin rash (urticarial) 7-10 days after treatment
1-3 days after treatment if repeated dose s
(Delayed IgE mediated reaction)
147
What happens in anaphylactic reaction to penicillin?
Angioedema
Bronchospasm
Hypotension
148
Which antibiotics increase warfarin's anticoagulation effects?
Tetracycline, Cephalosporin, Broad Penicillin and tazocin
149
Example of 5th generation cephalosporin?
Ceftaroline fosamil
150
What bacteria does ceftazidime have good activity against?
Pseudomonas
151
What infection is telavancin used for?
HAP
152
What is the most common used aminoglycoside?
Gentamicin
153
What infections are gentamicin solely used for?
```
Bacterial endocarditis ( with other abx)
Iisteria Meningitis and other CNS infection
Pseudomonas aeruginosa
```
154
What is streptomycin used for?
Treatment of mycobacterium tuberculosis
155
Why are gram +ve and anaerobics resistant to aminoglycoside
Do not contain the oxygen transporting system
156
What effect do macrolides have on
a) warfarin
b) statin
a) can lead to bleeding
| b) can lead to myopathy
157
What effect do erythromycin and clarithromycin have on drugs that are metabolised by cytochrome p450?
Increase their plasma concentration as cytochrome p450 metabolism is being blocked
158
What MSK side effect does clarithromycin have?
Myalgia and arthralgia
159
What drugs should macrolides and quinolones not be used with in risk of further prolongation of the QT interval?
SSRI's, antipsychotics, amiodaron, quninine and each other
160
Give example of gram -ve bacteria in which quinolones are effective against?
```
Campylobacter
Pseudomonas
Shigella
Salmonella
NEISSERIA
```
161
What is oral ciprofloxacin used for?
Pseudomonas aeruginosa
162
What is the interaction of quinolones and NSAIDS?
Increase risk of seizures
163
What is the interaction of quinolones and prednisolone?
Increase risk of tendon rupture
164
What drugs reduce the absorption of quinolones?
Drugs that contain divalent cations such as calcium and antacids
165
Why should quinolones be avoided in children and young adolescents?
Causes arthropathy
166
Why is quinolones usually second and third line treatment?
Due to the rapid development of resistance to them and their association with C.diff infection
167
What is a MSK side effect of quinolones?
Inflammation and rupture of muscle tendons
168
What cardiac side effect of quinolones?
Increase QT interval
169
What is a severe side effect of trimethoprim?
It can cause haematological disorders= should be avoided in the elderly
170
Trimethoprim can cause hyperkalemia. Therefore what drugs should be avoided?
Aldosterone antagonist, ACH inhibitor and angiotensin receptor blocker
171
What is the common side effects of trimethoprim?
Nausea and vomiting
Sore throat
Rash
172
What are the three abx of choice for UTI?
Trimethoprim
Amoxicillin
Nitrofurantoin
173
What abx are involved in the eradication of H.pylori?
PPI + clarithromycin + either amoxicillin or metronidazole
174
Who are particularly susceptible to adverse affects of TRIMETHOPRIM?
Neonates, elderly and HIV patients
175
What respiratory tract infections are moxifloxacin and levofloxacin used in? When are they used?
CAP
Sinusitis
Chronic bronchitis
2nd or 3rd line treatment
176
What 4 abx are contradictive in patients with myasanthia gravis?
Tetracylcine
Aminoglycoside
quinolones
marcolides
