Effects of concurrent drug therapy and of feeding on plasma chloramphenicol levels after oral administration of chloramphenicol in dogs.

On separate occasions, five fasted adult greyhounds were dosed orally with 50 mg chloramphenicol/kg, both alone and in conjunction with other drugs. The same five dogs were later given 50 mg chloramphenicol/kg when fed ad lib. Chloramphenicol levels in plasma were determined at intervals after dosing. The intial plasma chloramphenicol levels were higher when the drug was administered concurrently with calcium lactate tablets (50 mg/kg) or a proprietary enteric mixture containing kaolin, pectin, aluminium hydroxide and belladonna extract. Lower plasma levels resulted when the antibiotic was given with dry extract of belladonna (20 mg/dog) or intravenous chlorpromazine (2 mg/kg). There was no significant effect with coated ferrous gluconate tablets (30 mg/kg). Feeding ad lib increased the initial chloramphenicol levels, but produced lower levels subsequently.