tetracyclines classification, advantages and adverse effect in easily understandable for undergraduates

1. TETRACYCLINES
BY: BIBI UMEZA

2. TETRACYCLINES
• Tetracylines are group of broad spectrum
antibiotics compounds that having common
four cyclic ring structure.

3. • They are so called because of their effectiveness
against a wide range of microorganisms, such as
Gram-positive and gram-negative cocci
- S.pneumoniae,N.gonorrhoeae

4. Gram-negative bacilli
-V.cholerae, H. influenzae
Gram-positive bacilli
- B.anthracis, Listeria

5. Others-
- mycoplasma, Rickettsiae

6. CLASSIFICATION OF
TETRACYCLINES
SHORT ACTING INTERMEDIAT LONG ACTING
TETRACYCLINE DEMECLOCYCLINE DOXYCYCLINE
OXYTETRACYCLINE METHACYCLINE MINOCYCLINE
t1/2= 6-12 hrs t1/2= 16-18 hrs t1/2= 18-24

7. Mechanism of action
Tetracyclines
actively taken up by susceptible bacteria
bind reversibly to 30s ribosomal subunit
Prevent binding of aminoacyl tRNA to mRNA-ribosome complex
Prevent the addition of amino acid to the growing peptide chain
Inhibit bacteria protein synthesis (Bacteriostatic)

9. Resistance
• Bacterial resistance to tetracyclines is due to:
• Decrease influx or increased influx of
tetracycline.
• Inactivation of drug by enzymes.

10. Phamacokinetics
Drugs Route of
administration
Absorption
from the gut
Half-life
t1/2 (hours)
Dosage
Chlortetracycline
Oxytetracycline
tetracycline
Oral incomplete 6-12 250-500 mg QID
Demeclocycline
methacycline
Oral incomplete 16-18 300-500 mg BD
Doxycycline
minocycline
Oral high 18-24 100 mg BD or OD

11. Therapeutic uses
• Rickettsial infections:
Epidemic typhus,
Rocky mountain
spotted fever, scrub
typhus, rickettsial pox
and Q fever.
• Mycoplasma
pneumoniae infections

13. • Chlamydial infections:-
-lymphogranuloma
venereum,
-Psittacosis
• Cholera : fluid and
electrolyte
replacement.
• Brucellosis
• Plague: Doxycycline is
highly effective.
• Anthrax and
leptospirosis

14. Therapeutic uses.
• Lyme disease: caused by a
spirochete
• Granuloma inguinale
• Acne: Low doses of
tetracyclines are used
• Malaria
• Amoebiasis
• Syndrome of inappropriate
ADH secretion
• Leprosy

15. Advantages of doxycycline
• It can be administered orally as well as intravenously.
• Highly potent.
• Completely absorbed after oral administration.
• Food does not interfere with its absorption.
• Longer duration of action (t1/2=24 hours)
• Can be given to patients with renal failure, as it is
excreted primarily in bile.

16. Adverse effects
• Gastrointestinal: GI irritation manifestated as
nausea, vomiting, epigastric distress, abdominal
discomfort and diarrhoea.
• Phototoxicity: it is particularly seen with
demeclocycline and doxycycline.
• Hepatotoxicity: more likely to occur in pregnant
women.

17. Adverse effects
• Renal toxicity: demeclocycline may produce
nephrogenic diabetes insipidus.
• Superinfection: causes alteration of the gut
flora,pseudomembranous colitis, diarrhoea, fever,
abdominal pain and stool mixed with blood and
mucus.

18. • Effects on bones and
teeth: permanent
brownish discolouration
of deciduous teeth and
affect linear growth of
bones.
• May cause increased
intracranial pressure
(pseudotumour cerebri)
in infants.
• Hypersensitivity
reactions: skin rashes,
fever, urticaria, exfoliative
dematitis, etc.

19. Precautions
• Tetracyclines should not be used during pregnancy,
lactation and in children.
• Should be avoided in patients on diuretics.
• Do not mix injectable teracyclines with pencillin-
inactivation occur
• Do not inject tetracycline i.m or intrathecally.

20. Tigecycline
• It is a first member of a new class of synthetic
tetracycline analogues (glycylcyclines).
• Tigecycline is a derivative of minocycline, and was
introduced in 2005.
• Which are active against most bacteria that have
developed resistance to the classical tetracyclines.
• They have broad spectrum of activity

21. Advantages of tigecycline
• It is effective against organisms which are resistant
to tetracyclines.
• Mycobacteria are also susceptable.
• Administered intravenously

22. Adverse effect of tigecycline
• Nausea and vomiting.
• Brown discolouration of the teeth in children

23. THANK YOU