Abstract

Plasma concentrations of 1–3 mcg/ml are normally obtained when 250 mg tetracycline is given by mouth every six hours. These concentrations are usually adequate; intramuscular or intravenous injections are needed only for patients who cannot swallow or reliably absorb the drug, or when high initial plasma concentrations are essential. Bacterial resistance to tetracyclines is common and, whenever possible, the nature and the sensitivity of the organisms should be determined before they are used.