Oxytetracycline

Indications

Oxytetracycline is indicated in-

Respiratory tract infections
Mycoplasma pneumonia
Urinary tract infections
Sexually transmitted diseases: Infections due to Chlamydia trachomatis including uncom-plicated urethral, endocervical or rectal infections, non gonococcal urethritis, chancroid, granuloma inguinale, lymphogranuloma venereum, gonorrhoea, syphilis
Skin infections: Acne and rosacea
Ophthalmic infections: Trachoma
Rickettsial infections
Other infections: Psittacosis, brucellosis, cholera, acute
intestinal amoebiasis etc.

Pharmacology

Oxytetracycline inhibits cell growth by inhibiting translation. It binds to the 30S ribosomal subunit and prevents the amino-acyl tRNA from binding to the A site of the ribosome. The binding is reversible in nature. Oxytetracycline is lipophilic and can easily pass through the cell membrane or passively diffuses through porin channels in the bacterial membrane.

Dosage And Administration

Adults: 250-500 mg every 6 hours. Food, milk and some dairy products interfere with the absorption of Tetracyclines. So Tetracyclines should be given one hour before or two hours after meals.

Interaction

Antacids containing Aluminium, Calcium, Magnesium, Zinc or Iron salts may impair the absorption of Oxytetracycline. In long term therapy, Tetracyclines depress plasma prothrombin activity and reduced doses of concomitant anticoagulants may be necessary. A few cases of pregnancy or breakthrough bleeding have been attributed to the concurrent use of Tetracyclines or Oxytetracyclines with oral contraceptives.

Contraindications

Oxytetracycline should not be used with patients who are hypersensitive to Tetracyclines. It should not be used in children under 12 years of age. It is contraindicated in pregnant women because of tooth staining in the fetus and possible growth retardation effects.

Side Effects

Side effects of Oxytetracycline, which have been reported in some patients, are anorexia, nausea, vomiting, diarrhoea, glossitis, skin rashes and urticaria.

Pregnancy And Lactation

Results of animal studies indicate that tetracyclines cross the placenta, are found in fetal tissues and can have toxic effects on the developing fetus. Evidence of embryotoxicity has also been noted in animals treated early in pregnancy. Tetracyclines are present in the milk of lactating women who are taking a drug in this class.