Overview
DESCRIPTION Tetracycline is a yellow, crystalline powder. Tetracycline is stable in air but exposure to strong sunlight causes it to darken. Its potency is affected in solutions of pH below 2 and is rapidly destroyed by alkali hydroxide solutions. Tetracycline is very slightly soluble in water, freely soluble in dilute acid and in alkali hydroxide solutions, sparingly soluble in alcohol, and...
Mechanism of Action
CLINICAL PHARMACOLOGY Tetracyclines are readily absorbed and are bound to plasma protein in varying degrees. They are concentrated by the liver in the bile and excreted in the urine and feces at high concentrations in a biologically active form. Microbiology Tetracyclines are primarily bacteriostatic and exert their antimicrobial effect by the inhibition of protein synthesis by binding to the 30S ribosomal subunit. Tetracycline is active against a broad range of gram- negative and gram-positive organisms. The drugs in the tetracycline class have closely similar antimicrobial spectra, and cross-resistance among them is common.
Indications
- INDICATIONS AND USAGE To reduce the development of drug-resistant bacteria and maintain the effectiveness of tetracycline hydrochloride and other antibacterial drugs, tetracycline hydrochloride should be used only to treat infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
Common Doses
- 500 mg
- 250 mg
- 10 mg
- 20 mg
Dosage
DOSAGE AND ADMINISTRATION Adults Usual daily dose, 1 gram as 500 mg twice a day or 250 mg four times a day. Higher doses such as 500 mg four times a day may be required for severe infections or for those infections which do not respond to the smaller doses. For pediatric patients above eight years of age Usual daily dose, 10 mg/lb to 20 mg/lb (25mg/kg to 50 mg/kg) body weight divided in four equal doses. Administration of adequate amounts of fluid with the capsule formulation of tetracycline is recommended to wash down the drug and reduce the risk of esophageal irritation and ulceration (see...
Contraindications
- CONTRAINDICATIONS This drug is contraindicated in persons who have shown hypersensitivity to any of the tetracyclines.
Side Effects
- ADVERSE REACTIONS Gastrointestinal: anorexia, nausea, epigastric distress, vomiting, diarrhea, glossitis, black hairy tongue, dysphagia, enterocolitis, and inflammatory lesions (with Candida overgrowth) in the anogenital region. Esophagitis and esophageal ulceration have been reported in patients receiving particularly the capsule and also the tablet forms of tetracyclines. Most of the patients were reported to have taken medication immediately before going to bed (see DOSAGE AND ADMINISTRATION ). Teeth : permanent discoloration of teeth may be caused during tooth development.
Interactions
- Drug Interactions Since bacteriostatic drugs may interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracycline in conjunction with penicillin or other bactericidal antibacterials. Because the tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage. Absorption of tetracyclines is impaired by antacids containing aluminum, calcium or magnesium and preparations containing iron, zinc, or sodium bicarbonate.