- Are primarily bacteriostatic
- Inhibit protein synthesis by binding to 30s ribosome in susceptible organism
- Subsequent to such binding, attachment of aminoacyl-t-RNA to acceptor (A) site of mRNA-ribosome complex is interfered with
- As a result, peptide chain fails to grow
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- Irritative effects-
- Oral- Epigastric pain, nausea, vomiting, diarrhea, Odynophagia and esophageal ulceration- due to release of material of capsule during swallowing especially with doxycycline
- IM- Very painful
- IV- thrombophlebitis
- Organ Toxicity-
- Liver damage- Fatty infiltration and jaundice
- Kidney damage- Fanconi anemia by outdated tetracycline
- Phototoxicity- sunburn like esp. with doxycycline
- Teeth and bone- Chelating property, gets deposited in developing bone and teeth, brown discoloration, ill formed tooth susceptible to caries
- Antianabolic effect-reduce protein synthesis and have catabolic effect
- Increased ICP
- Diabetes insipidus- Demeclocycline antagonizes ADH action
- Vestibular toxicity- Minocycline can cause ataxia, vertigo and nystagmus
- Hypersensitivity- Skin rash, urticaria
- Superinfection- Marked suppression of resident flora, Intestinal
superinfection by Candida albicans is most prominent, Psudomembranous enterocolitis is rare. |
- Empirical therapy– initial treatment of mixed infection, although combination of B-lactam, and AG is much preferred
- DOC in:
- Veneral disease– Chlamydia urethritis/endocervicitis, LGV, Granuloma inguinale
- Atypical pneumonia
- Cholera
- Brucellosis
- Plague
- Relapsing fever– Borrellia recurrentis
- Rickettsial infection– typhus, Q fever, RMSF
- UTI
- Community acquired pneumonia- when more selective antibiotic cannot be used
- Acne vulgaris- Propionibacterium acne is sensitive to tetracycline
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