pharmacodynamics of tetracycline

2. Amin ullah Daavi
Roll no 215

3. Introduction.
Chemical structure of doxycycline.
Mechanism of action.
Resistance.
Antimicrobial activity.
Clinical uses.
Adverse effect.
Contraindication.

4.  Doxycycline is a
synthetic broad
spectrum
antibiotic drug
derived from
tetracycline which
inhibit protein
synthesis.

6. A. Short acting(6-8 hours)
 Chlortetracycline
 Oxytetracycline
B. Intermediate acting (12 hrs)
 Demeclocycline
 Methacycline
C. Long acting(16-18 hours)
 Doxycycline
 Minocycline

7. Doxycycline reversiably bind
to 30s subunit at A site
Block the binding of
aminoacyl t-RNA to m-RNA
inhibit the addition of new
aminoacid to growing peptide
chain
Stop the translation process

8. Mechanism of resistance.
Impaired influx or increase efflux
Ribosomal protein production that
interfere the binding of doxycycline
Enzymatic inactivation

9. Tet (AE)efflux pump Resistance.
Tet(M) efflux pump Resistance.
Tet(K) efflux pump susceptible.

10. Doxycycline are sensitive against
 Many gram-positive and gram-negative bacteria.
 Bacillus anthracis.
 Staphylococcus aureus.
 Listeria monocytogenes.
 Mycoplasma pneumoniae.
 Chlamydiae and spirochetes.
 Rickettsiae .
 Vibrio cholera.
 Neisseria gonorrhoea.
 Haemophilus influenzae.

11.  Doxycyline is the drug of choice in infaction caused
by
 Mycoplasma Pneumonia.
 Rickettsiae Rocky mountain spotted
fever and rickettsial pox.
 Chlamydia Trachoma and peittacosis.
 Vibrio Cholera.
 Bacillus anthracis Anthrax.
 Spirochetes Lyme’s disease.

12. Doxycycline use in a regimen for
treatment of gastic ulcer caused by
helicobacter pylori
Also with amino glycoside for plague,
tularemia and brocellosis

13. A. Gastrointestinal adverse effects
Nausea vomiting and diarrhea.
B. Bony structures and teeth
During pregnancy it can deposited in fetal
teeth leading to fluorescence ,discoloration
and enamel dysplasia.
C. Liver toxicity
Hepatic toxicity leading to hepatic
necrosis.

14. D. Kidney
toxicity.
E. Local tissue
toxicity.
F. Vestibular
toxicity.
G. Photosensitizat
ion.

15. Hypersensitivity
Pregnancy
Infants and
children

16. Basic and clinical pharmacology
(11th edition)
Chapter 44(796-799)
Lippincoatt’s illustrated reviews
Pharmacology (4th edition)
chapter 32(373-376)
 httpwww.drugs.comdoxycycline.html