Pharmacology PPT

1. Macrolides
Dr Chintan Doshi

2. Introduction
• These are antibiotics having a macrocyclic
lactone ring with attached sugars

3. Classification of macrolides
• Erythromycin
• Azithromycin
• Clarithromycin
• Roxithromycin
• Spiramycin
• Telithromycin

4. Mechanism

5. • Bacteriostatic at low but cidal (for certain
bacteria only) at high concentrations
• Gram-positive bacteria accumulate
erythromycin intracellularly by active
transport
• Activity is enhanced in alkaline medium
• Acts by inhibiting bacterial protein synthesis
• Combines with 50S ribosome subunits and
interferes with ‘translocation

6. Contd.
• Peptide bond formation between the newly
attached amino acid and the nacent peptide
chain at the acceptor (A) site
• The elongated peptide is translocated back to
the peptidyl (P) site
• Prevented by erythromycin

7. •USES

8. A. As an alternative to penicillin
• Streptococcal pharyngitis, tonsillitis,
mastoiditis
• Community acquired respiratory infections
caused by pneumococci and H. influenzae
• Prophylaxis rheumatic fever and SABE
• Diphtheria:
– 7 day treatment is recommended
• Tetanus:

9. Contd.
• Syphilis and gonorrhoea
• Leptospirosis:150 mg 12 hrly for 7 days

10. B. As a first choice drug for
• Atypical pneumonia caused by Mycoplasma
pneumoniae
• Whooping cough
– 1–2 week course is the most effective treatment
for eradicating B. pertussis from upper respiratory
tract
• Chancroid: 150 mg 12 hrly for 7 days

11. As a second choice drug in
• Campylobacter enteritis
• Legionnaires’ pneumonia
• Chlamydia trachomatis
• Penicillin-resistant Staphylococcal infections
– not effective against MRSA

12. Roxithromycin
• Similar to erythromycin except
• More preferred for otitis media,sinusitis and
pneumonia caused by moraxella catarhalis
and legionella

13. ADR
• Gastrointestinal
– Mild-to-severe epigastric pain
– Nausea, vomiting
– Diarrhoea is occasional: stimulation of motilin
receptors
– Cholestatic hepatitis → estolate ester
• Reversible hearing impairment
• Hypersensitivity

14. Drug interaction
• CYP3A4 inhibitor

15. Acid stable , Spectrum →wider
H.Pylori , MAC(mycobacterium avium complex)
Uses
URTI , atypical pneumonia
H.Pylori , MAC →in AIDS
Drug interactions → CYP3A4 inhibitor

16. •Azithromycin

17. Advantages
• Expanded spectrum
• Improved pharmacokinetics
• better tolerability
• Less drug interactions
• Convent once daily dosing schedule

18. PK features
• acid-stability
• rapid oral absorption
• larger tissue distribution and intracellular
penetration
• Particularly high concentrations are attained
inside macrophages and fibroblasts

19. USES
• Legionnaires’ pneumonia: 500 mg OD oral/
i.v. for 2 weeks.
• Chlamydia trachomatis:1 g single dose
• Lymphogranuloma venerum
• Chlamydial pneumonia: drug of choice
• Donovanosis caused by Calymmatobacterium
granulomatis
• Chancroid and PPNG urethritis:1 g single dose

20. Other uses
• Pharyngitis, tonsillitis, sinusitis, otitis media
• Pneumonias, acute exacerbations of chronic
bronchitis
• streptococcal and some staphylococcal skin
and soft tissue infections
• prophylaxis and treatment of MAC in AIDS
patient

21. Contd.
• MDR typhoid
• Toxoplasmosis

22. ADR
• Mild gastric upset
• Abdominal pain
• Headache and dizziness

23. • Drug of choice for treatment of infections
caused by MRSA is:
• (a) Metronidazole
• (b) Vancomycin
• (c) Imipenem
• (d) Clindamycin

24. • The antibiotic causing pseudomembrane
colitis is:
• (a) Clindamycin
• (b) Garamycin
• (c) Erythromycin
• (d) Vancomycin

25. • Antibiotic which is effective as a single dose
therapy
• for trachoma is:
• (a) Doxycycline
• (b) Clarithromycin
• (c) Azithromycin
• (d) Erythromycin

26. • Drug of choice for Treponema pallidum is:
• (a) Penicillin G
• (b) Tetracycline
• (c) Azithromycin
• (d) Doxycycline

27. • Which of the following antibacterial causes
both ototoxicity and nephrotoxicity:
• (a) Methicillin
• (b) Vancomycin
• (c) Clindamycin
• (d) Azithromycin

28. • All of the following are common
antimicrobial agents used in treatment of
typhoid fever except:
• (a) Ceftriaxone
• (b) Quinolones
• (c) Clindamycin
• (d) Azithromycin

29. • The drug of choice in lymphogranuloma
venereum is:
• (a) Penicillin
• (b) Ciprofloxacin
• (c) Tetracycline
• (d) Erythromycin

30. • Drug inhibiting bacterial protein synthesis are
all
• except:
• (a) Aminoglycosides
• (b) Chloramphenicol
• (c) Clindamycin
• (d) Sulfonamides

31. • Widest spectrum aminoglycoside is –
• (a) Streptomycin
• (b) Amikacin
• (c) Framycetin
• (d) Netilmicin

32. • Red man syndrome is due to:
• (a) Vancomycin
• (b) Polymyxin
• (c) Rifampicin
• (d) Teicoplanin

33. • Drug of choice in pertussis is:
• (a) Penicillin
• (b) Doxycycline
• (c) Erythromycin
• (d) Ciprofloxacin

34. • Drug effective against pseudomonas is:
• (a) Penicillin G
• (b) Gentamicin
• (c) Tetracycline
• (d) Chloramphenicol

35. • Gray baby syndrome is caused by:
• (a) Chlorpromazine
• (b) Chloramphenicol
• (c) Phenytoin
• (d) Gentamycin

36. • Which of the following is not nephrotoxic?
• (a) Tobramycin
• (b) Kanamycin
• (c) Ampicillin
• (d) Amphotericin B

37. • A diabetic patient develops cellulitis due to
Staphylococcus aureus that was found to be
methicillin resistant on the antibiotic
sensitivity testing. All of the following
antibiotics will be appropriate EXCEPT:
• (a) Vancomycin
• (b) Imipenem
• (c) Teicoplanin
• (d) Linezolid

38. THANK YOU