Intramuscular meropenem in the treatment of bacterial infections of the urinary and lower respiratory tracts

In three open, multicentre, prospective randomised studies, the efficacy and safety of meropenem were assessed and compared with ceftazidime (Study 1) and imipenem/cilastatin (Studies 2 and 3) in 864 patients; 417 with urinary tract infections (UTI) and 447 with community acquired lower respiratory tract infections (LRTI). All the antibiotics were administered by intramuscular injection. Clinical and bacteriological responses were assessed at the end of therapy and at follow-up (2-4 weeks for LRTI, 4-6 weeks for UTI). The clinical response rate in UTI at the end of therapy was 93-100% for meropenem 500 mg tds compared with 94-95% for ceftazidime 500 mg tds; for meropenem 500 mg bd it was 97%, significantly higher than that for imipenem/cilastatin 500 mg bd which was 90% (P=0.03). At follow-up, the response rates were 90% for meropenem tds compared with 81-85% for ceftazidime 500 mg tds and 81% for meropenem bd compared with 78% for imipenem/cilastatin 500 mg bd. The clinical response rate in LRTI at end of therapy was 93% for meropenem 500 mg tds, compared with 92% for ceftazidime 1g tds; for meropenem 500 mg bd the clinical response rate was 96%, compared with 91% for imipenem/cilastatin 500 mg bd (P=0.054). At follow-up, the clinical response rates were 96%, 89%, 93% and 96%, respectively. The bacteriological response rates at 5-9 days post-therapy in UTI were 61-84% in patients treated with meropenem 500 mg tds, compared to 73-82% in patients treated with ceftazidime 500 mg tds; the rates for meropenem 500 mg bd and imipenem/cilastatin 500 mg bd were each 75%. At follow-up, the response rates were 40-72%, 57-70%, 51% and 49%, respectively. In LRTI, bacteriological response rates at the end of therapy were 91% for both meropenem 500 mg tds and ceftazidime 1g tds, and 91% for meropenem 500 mg bd compared with 86% for imipenem/cilastatin 500 mg bd. At follow-up, the response rates were 87%, 77%, 84% and 79%, respectively. All treatments were well tolerated. In these studies, intramuscular meropenem proved to be an effective and well tolerated treatment for LRTI and UTI