Treatment of bacterial infections with intravenous or intramuscular imipenem/cilastatin

Abstract

We treated 43 patients for a variety of infections using an intramuscular formulation of imipenem/cilastatin, at 1 or 1.5 g/day, in two doses. In 11 cases of severe infection the intramuscular formulation was given after the patients had been clinically stabilized by intravenous treatment. The infections included pyelonephritis (25), pneumonia (nine), soft tissue infection (three), sepsis (two), intra-abdominal abscess (two), maxillary sinusitis (one) and osteomyelitis (one). Forty-one out of forty-three (95%) patients were cured or improved by the intramuscular therapy and in 28/36 (78%) the bacterial infection was eradicated. In 10 patients given 500-mg doses of imipenem, mean peak serum levels reached 10.9 μg/ml, falling to 4.5 μg/ml 8h after a dose; after 12 h the drug concentration had fallen to 2 μg/ml in eight patients and in two the drug was not detectable. Clinical and laboratory adverse effects were mild, and similar in type but less common than those noted with the intravenous formulation. The intramuscular injections were relatively well tolerated in all but two patients who had been given 750-mg doses without lidocaine. The intramuscular formulation of imipenem therefore proved a good alternative to intravenous treatment for bacterial infections of moderate severity.