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MBBS I CPRS > L71 – Drugs Used in the Treatment of Pulmonary Infections > Flashcards

L71 – Drugs Used in the Treatment of Pulmonary Infections Flashcards

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1
Q

Symptom of tonsilitis?

A

Local infection of tonsils = red, swollen with exudate on the surface

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2
Q

What are some upper respiratory tract infections?

A

Pharyngitis
Tonsilitis
Sinusitis and otitis media

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3
Q

What is acute bronchitis? Symptoms? Pathogen?

A

Inflammation of bronchi

fever, cough, wheezing and “noisy chest“

Respiratory syncytial virus (RSV), parainfluenza virus, adenovirus

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4
Q

What is acute BRONCHIOlitis? Symptoms? Pathogen?

A

Inflammation and narrowing of terminal bronchioles

fever first and followed by
respiratory distress and wheezing

RSV, parainfluenza virus

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5
Q

Some general symptoms of pneumonia? Type of pathogens?

A

fever, respiratory distress and cyanosis

Primary community-acquired: bacterial infections are more prominent

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6
Q

Name all the classes of antibiotics used to treat primary community-acquired pneumonia (bacteria)?

A
  • B-lactams:
    1) Cephalosporins (3rd gen)
    2) Penicillins +/- B-lactamase inhibitor
  • Macrolides
  • Tetracyclines
  • Fluoroquinolones
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7
Q

When is Fluoroquinolone used for primary community -acquired pneumonia?

A

For severe gram -ve bacterial infection

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8
Q

Give the bacterial component target for all classes of antibiotics used for primary comminity=acquired pneumonia?

A

B-lactams - cell wall peptidoglycan synthesis

Tetrcyclines - 30s inhibitor

Fluoroquinolones - Nucleic acid synthesis

Macrolides - 50s inhibitor

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9
Q

Is B-lactams bactericidal or static?

A

Bactericidal

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10
Q

What is the MoA of B-lactams?

A

Cross bacteria cell wall > bind to penicillin-binding-protein > inhibit these transpeptidase enzymes > cannot make peptidoglycan cross links between NAM subunits

Activate autolysins in bacteria to destroy existing cell wall > cell burst through osmotic pressure

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11
Q

Compare the entry of B-lactams in gram +ve and-ve bacteria?

A

Gram +ve: no outer membrane, no porin channel&raquo_space; antibiotics go in by diffusion&raquo_space; less resistance

Gram -ve: if porin channel is impaired&raquo_space; antibiotic cannot go in

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12
Q

What are some resistance mechanisms specific for gram -ve bacteria against B-lactams?

A
  1. Loss of porins

2. Efflux pump

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13
Q

What are some resistance mechanisms used by both gram+ve and -ve bacteria?

A

Altered/ Modified PBP, penicillin binding protein (e.g. mecA)

B-lactamase

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14
Q

What are the 4 classifications of penicillins?

A

1) Narrow spectrum, B-lactamase-SENSITIVE
2) Narrow spectrum, B-lactamase- RESISTANCE
3) Extended spec. AMINOpenicillins
4) Extended spec. ANTI-PSEUDOMONAL penicillins

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15
Q

What are some limitations of penicillin G?

A

Narrow spectrum
Short duration of acid
Poor penetration into CNS

Unstable in stomach acid
Useless against B-lactamase
Allergy for some

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16
Q

What are some COMMON adverse effects of Penicillin G?

A

Diarrhea

Seizures (esp. in epileptic patients)

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17
Q

What are some RARE adverse effects of Penicillin G?

A

Low toxicity > allergy

Acute interstitial nephritis

Decreased coagulation

Cation toxicity

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18
Q

How can antistaphlyococcal penicillin resist B-lactamase?

A

BULKY SIDE GROUPS can block B-lactamases that hydrolyzes the B-lactam ring

Resist acid degradation

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19
Q

Name some antistaphlyococcal penicillin (B-lactamase-resistant penicillins)? which one is highly nephrotoxic?

A

methicillin (highly nephrotoxic)
Cloaxacillin
flucoxacillin
oxacillin

-xacillin

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20
Q

When is antistaphlyococcal penicillin used and what is one disdavantgae?

A

Used to B-lactamase resistant STAPHYLOCOCCAL infections

Harder to penetrate cell membrane due to bulky side chain> less effective

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21
Q

Extended spectrum aminopenicillins are effective against which bacteria?

A

Gram +ve and Gram –ve cocci, Gram –ve
bacill

Not effective against Pseudomonas spp.

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22
Q

When is Extended spectrum aminopenicillins used?

A

 Excellent oral agent for bacterial sinusitis, bronchitis

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23
Q

What are the advantages and disadv. of Extended spectrum aminopenicillins ?

A

Advantages: Acid stable, good oral bioavailability (amoxicillin > ampicillin)

Disadvantage: Do not resist B-lactamases

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24
Q

Name 2 Extended spectrum aminopenicillins?

A

Ampicilin

Amoxicillin

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25
Name 2 classes and 3 examples of extended spectrum antipseudomonal penicillins?
 Carboxypenicillins (e.g. carbenicillin, ticarcillin)  Ureidopenicillins (e.g. piperacillin )
26
What are some advantages and disadvantages of extended spectrum antipseudomonal penicillins?
Good: effective against many gram -ve bacilli and very effective against Pseudomonas aeruginosa (unlike aminopenicillins) Bad: sensitive to B-lactamses, acid labile
27
What are B-lactamase inhibitors Name 3
= potent irreversible inhibitor of many β-lactamases producing bacteria, esp. in respiratory tract E.g.: 1. Clavulanate (clavulanic acid) 2. Sulbactam 3. Tazobactam
28
What drugs is usually given with B-lactamase inhibitors and why?
normally formulated / combined with a broad spectrum penicillin derivative >> to protect them from enzymatic inactivation by β-lactamases
29
Name the 4 combo preparations of B-lactamase inhibitors? Combo broad spectrum penicillin and B-lactamase inhibitor
 Augmentin (amoxicillin + clavulanic acid = co-amoxiclav  Unasyn (ampicillin + sulbactam = sultamicillin)  Timentin (ticarcillin (= carboxypenicillin) + clavulanic acid)  Tazocin (piperacillin (= ureidopenicillins) + tazobactam)
30
Cephalosporin is effective against which bacteria? Bacteriocidal or static?
``` Broad spectrum (vs. Gram +ve, Gram –ve, some vs. anaerobes) ** improved activity against gram -ve bacteria ** ``` Bactericidal
31
Name some first, second, third, fourth, fifth gen cephalosporins?
First: cefadroxil 2nd: Cedaclor 3rd: Ceftriaxone 4th: Cefepime 5th: Ceftaroline
32
What is 1st gen cephalosporin best used against?
gram +ve | community acquired enterobacter
33
What is 2nd gen cephalosporin best used against?
both grams
34
What is 3rd gen cephalosporin best used against?
Mainly against gram -ve
35
What is 4th adn 5th gen cephalosporin best used against?
4th: wide spectrum + B-lactamase resistant 5th: wide spectrum + MRSA active
36
Which cepahlosporins can be given orally unlike others that are given IV or IM dur to poor oral absorption?
cefalexin cefuroxime ceftibuten
37
Which gen cephalosporin has good CSF penetration?
All gens are shit except 3rd gen
38
What is the half-life and path of excretion for cephalosporins?
long half-life (e.g. 6-8hr) Renal secretion (except ceftriaxone > bile excretion)
39
Adverse effects of cephalosporin? aside from being very expensive
Oral admin> GI irritation Allergic Infrequent nephrotoxicity
40
Compare the spectrum between tetracyclines and macrolides?
Tetra = broad Macrolides = Moderate
41
Difference between erthyromycin vs clarinthromycin and azithromycin?
Erythromycin (= prototype) clarithromycin and azithromycin are new analogues >> improved pharmacokinetic properties, broader antibacterial spectrum
42
What is the MoA of macrolides?
Bind irreversibly to a site on 50S subunit of the bacterial ribosome >> inhibit translocation of the polypeptide chain from A-site to P-site catalyzed by peptidyltransferase >> block movement of peptidyl tRNA from acceptor to donor site >> incoming tRNA cannot bind to the still occupied acceptor site >> inhibit bacterial protein synthesis
43
When is erythromycin used?
Active vs. Gram +ve organisms (same as penicillin G) >> narrow spectrum For patients allergic to penicillins
44
When is Clarithromycin used?
 Slightly greater activity than erythromycin  Higher activity vs. intracellular pathogens, e.g. Chlamydia, Legionella, Moraxella  Also has activity vs. Mycobacterium leprae, Toxoplasma gondii, H.pylori
45
When is Azithromycin used?
 Slightly less active than erythromycin vs. Gram +ve  But enhanced activity vs. some Gram –ve organisms, e.g.Haemophilus influenzae
46
Rank the three macrolides antibiotics in terms of activity against gram +ve bacteria?
Clarithromycin > erythromycin > azithromycin
47
When is Telithromycin used?>
Different site of action >> | effective vs. macrolide-resistant strains
48
What is the difference in absorption between erythromycin and newer macrolides?
Newer macrolides are more acid stable (instead of labile in gastric acid) and better obsorbed
49
Are all macrolides orally absorbed?
Yes
50
Are all macrolides converted to an active metabolite?
All except Erthyromycin
51
Which of the 4 macrolides are extensively metabolised in body?
Erthyromycin and telithromycin
52
Which of the 4 macrolides are exreted in bile in an active form (undergo enterohepatic circulation)?
Erthyromycin and azithromycin
53
Which macrolide is metabolized to active 14-hydroxy metabolite and eliminated in urine?
Clarithromycin
54
What is the toxicity and therapeutic index of macrolifdes?
High therapeutic index, relatively non-toxic
55
What are some adverse effects of macrolides?
GI disturbances (due to stimulation of motilin receptors High dose of ethromycin can cause deafness Risk of arrhythmia Drug interactions (except azithromycin)
56
What respiratory tract infections are treated by macrolides?
Upper and Lower, including pharyngitis and tonsilitis
57
Macrolides is the drug of choice for which type of pneumonia?
Atypical Caused by Mcoplasma and Legionella
58
Macrolides is used to replace which drug in case of allergy?
Penicillin substitute for infections caused by staph. Strep. or pneumococci
59
Macrolides is used as an empirical therapy for which diseases?
Early outpatient pneumonia or bronchitis
60
Macrolides cannot be used for which patients?
Those with Liver disease
61
What are the 3 bacteria mechanisms against macrolides?
Effluc pump/ reduce permeability of cell membrane Modify 50s subunit (methylases encoded by erm) Release endogenous esterases to hydrolyse macrolides
62
Name 2 teracyclines? Which one it most popular?
Doxycycline *popular* Glycylcycline
63
Tetracycline spectrum and bacteriocidal or static?
Broad spectrum Bacteriostatic > inhibit protein synthesis
64
MoA of tetracyclines?
Bind to 30s ribosome > prevent access of tRNA to -site on mRNA- ribosome complex > block addition of amino acid to growing peptide > peptide not transferred to amino acid receptor
65
What type of infections if tetracyclines used against and why?
Not against common infections (reduce resistance) Treat uncommon infections (like Chlamydia, Mycosplasma, spirochetes infections)
66
Why can Doxycycline be used in renal impaired patients? *think absorption and excretion*
Absorbed orally Exreted in bile and not accumulate in kidney
67
What is Glycylcyclines effective against and not?
Effective: multi-resistant Gram +ve pathogens, some gram -ve, anaerobic organisms Ineffective: Protus and pseudomonas spp.
68
When is glycylcyclines used?
Treat complicated skin and soft tissue infections complicated intra-abdominal infections
69
Excretion of Glycylcycline?
Biliary excretion
70
Why is IM injection avoided for tetracyclines?
Cause local tissue irritation
71
What are some adverse effects of tetracyclines?
Permanent teeth discoloration in children Photosensitization (abnormal sunburn)\ GI irritation Hepatotoxicity (jaundice, fatty liver esp in pregnant women) ``` Vestibular problems (e.g. dizziness) ```
72
3 mechanisms in bacteria against tetracyclines?
Efflux pump/ impaired influx (porin) Synthesis of blocking molecule to interfere binding to 30s ribosome Production of tetracycline inactivating enzyme
73
Name the prototype quinolone and fluoroquinolone?
Quin = Nalidixic acid Fluoro = Ciprofloxacin
74
What is the difference between 1st gen and 2nd, 3rd gen quinolones/ fluoroquinolones?
2nd gen = expanded activity: against gram -ve some gram +ve atypical organisms
75
What is the general improvement of generations of quinolones?
Improve coverage against more gram -ve, +ve, atypical, anaerobic coverage
76
Name one 1st, 2nd, 3rd, 4th gen quinolone/ fluoroquinolone?
``` 1= nalidixic acid (urinary antiseptics) 2 = ciprofloxacin 3 = levofloxacin 4 = gemifloxacin ```
77
Spectrum and bactericidal or static for quinolones/fluoro--?
Bactericidal Broad spectrum
78
When is quinolone/ fluoro -- used? Which patients should not take it?
Treating lower respiratory tract infections | Contraindicated in children, nursing mothers, pregnancy arthropathy >> potential: problem in joints
79
What is the MoA for quinolones/ fluoro--?
Dual action: inhibit DNA gyrase and topoisomerase IV DNA gyrase: form quinolone-DNA- gyrase complex >> induce cleavage of DNA
80
Penetration, excretion of quinolones/ fluoro--?
 High tissue penetration  Mainly excreted into the urine
81
3 mechanisms for resistance in bacteria against quinolones/ fluoro--?
Overexpress efflux pump Reduce membrane permeability (less porin in gram -ve) bacterial chromosomal mutations for genes that encode for bacterial DNA gyrase, topoisomerase IV
82
Adverse effects of quinolones/ fluoro--?
GI disturbance CNS problems (e.g. confusion, dizziness) Photosensitivity Ruptured tendons in elderly
83
What drugs interact with quinolones/ fluoro--?
``` with cations (divalent and trivalent) ``` antacids, theophylline, warfarin, etc.
84
What is the outpatient therapy for pneumonia?
1) Macrolides, doxycycline or oral, anti-pneumococcal B-lactam e. g. Augmentin 2) Oral fluoroquinolone active against S. pneumonia for allergic patients or highly resistant infection
85
What is the inpatient therapy for pneumonia?
1) Parenteral B-lactam* + macrolide * e.g. ceftriaxone, ampicillin-sulbactam, cefotaxime 2) Fluoroquinolone in some patients
86
S. pneumonia is highly resistant to which antibiotics?
erthromycin, tetracycline, co-trimoxazole
87
3 things recommended by CDC against pneumonia?
Only prescribe antibiotics when its beneficial Use specific agent to target pathogen Use appropriate dose and duration
88
Adv. and Disadv. of amoxicillin.
Adv. = high dose kills 60-96% s, pneumonia Disadv. = cannot kill atypical or B-lactamase bacteria
89
Adv. and Disadv. of Augmentin (amoxicillin - clavulanate)?
Adv. = kill B-lactamase bacteria Disadv. = cannot kill atypical agents
90
Adv. and Disadv. of Cephalosporins?
Adv = active against all H. influenzae and 75-85% S. pneumoniae Disadv. = cannot kill atypical agents
91
Adv. and Disadv. of Macrolides.
Adv. = kill most common + atypical pthogens Disadv. = drug resistance problem
92
Adv. and Disadv. of F- quinolone?
Adv = kill H. influenzae + atypical pathogens Disadv. = less effective against S. pneumoniae, risk of increasing resisitance

MBBS I CPRS (78 decks)

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