Pharmacology

1. Tetracycline &
Chloramphenicol

2. Contents
• Tetracycline
•Classification
• Antibacterial spectrum
• Mechanism of action
•Antimicrobial spectrum and uses
•Adverse effect and drug interactions
• Chloramphenicol
• MOA and Resistance
• Antimicrobial spectrum and uses
•Adverse effect and drug interactions

5. Antibacterial spectrum
Highly active
Rickettsia
Chlamydia psittaci
C. Trachomatis
C. Pneumoniae
Spirochetes- Borrelia
burgdorferi
Atypical pathogens-
mycoplasma
pneumoniae
Gram negative bacilli-
vibrio cholerae, brucella
abortus
Propionibacterium acne
Gram positive bacilli-
bacillus anthracis, C.
Tetani

6. Mechanism of action

7. Resistance

8. Pharmacokinetics
Absorption
• GIT
• Chlortetracycline 30%
• Demeclocycline, oxytetracycline, tetracycline 60-820%
• Minocycline, doxycycline 95-100 %
Protein
binding
• Tetracycline, chlortetracycline, oxytetracycline 20-60%
• Demeclocycline, metacycline 40-80 %
• Doxycycline, minocycline 80-95%
Excretion
• Urinary
excretion
70-75 %

9. Clinical uses
 Tetracyclines are the drug of choice
• Rocky mountain spotted fever
• Typhus fever
• Psittacosis
• Granuloma inguinale
• Pneumonia
• Urethritis
• Atypical pneumonia
• Lyme disease

10.  Brucellosis
Tularaemia
 Plague
Bacteraemia
Abscesses
Trachoma

11.  conjunctivitis
 Amoebiasis--- along with metronidazole
 Malaria--- along with quinine / pyrimethamine
 Peptic ulcer
 Minocycline- used for the treatment of swimming pool granuloma
Tetracycline 250 mg, oxytetracycline 250 mg – 6 hrly
Demeclocycline 300mg 12 hrly
Doxycycline 100 mg 12 hrly
Minocycline 100 mg 12 hrly

12. Adverse effects
 Stomatitis
staining of teeth
 Hepatotoxicity
 Nephrotoxicity (except- doxycycline, minocycline)
 Fanconi’s syndrome
 Phlebitis
Minocycline- vestibular toxicity, skin pigmentation

13.  Doxycycline and Doxycycline- Photosensitivity
 Demeclocycline – nephrogenic diabetic insipidus

14. Drug interactions
•Reduce serum levels of
tetracycline
Barbiturates,
phenytoin,
carbamazine
•Potentiate anticoagulant
effect
Warfarin

15. Contraindication
 Children below the age of 10
 Tetracycline after expiry date can not be used

16. Chloramphenicol

19. Resistance
Decreased
permeability to
drug
Chloramphenicol
acetyltransferase

20. Antimicrobial spectrum and uses
 Active against
Gram negative organism- Salmonella typhi, haemophilus influenzae
 Gram positive organism-Streptococcus pneumoniae
 Anaerobic bacteria-Penicillin resistant Bacteroides fragilis
 Spirochetes
 Rickettsia

21.  Meningitis
 Conjunctivitis
 Endophthalmitis

22. pharmacokinetics
Chloramphenicol palmitate
Chloramphenicol
Distributed in body compartments, CSF
Glucuonyl conjugation
Metabolism
Pancreatic Lipase

23. Adverse effect
 Dose dependent bone marrow depression
 Idiosyncratic Aplastic anaemia
 Gray Baby Syndrome

24. Drug interactions
Chloramphenicol
Warfarin
Morphine
Paracetamol