Monitoring of effectiveness and safety of generic formulation of meropenem for treatment of infections at Siriraj Hospital.

In Siriraj Hospital, generic meropenem (Monem) has been available and was substituted for original meropenem, but the effectiveness and safety of using generic meropenem in a clinical setting are the main concern. From July 2007 to June 2009, hospitalized patients aged 18 or older who received meropenem for 48 hours were identified from the pharmacy database of Siriraj hospital. A retrospective study was conducted. Three hundred patients in each of original and generic meropenem groups were required to demonstrate non-inferiority of generic to original meropenem. The mean age of all patients was 63 years. Most of the patients had co-morbidities. Approximately 90% of the infections were health-care associated. Drug-resistant gram-negative bacteria including ESBL producing E. coli and K. pneumoniae, P. aeruginosa and A. baumannii account for nearly 50% of all organisms. No significant difference was found regarding characteristics, type or site of infection and pathogen between generic and original groups but for more patients in the original group having cardiovascular disease and more patients in the generic group receiving immunosuppressive agents. Eighty-two to 85% received meropenem with one of appropriate indications. No statistically significant difference occurred either in an overall favorable outcome (63% vs.70.4%, p = 0.07) or in overall mortality (38% vs. 32%, p = 0.17), as well as adverse effects between the original and the generic groups. Generic meropenem (Monem) was not inferior to original meropenem for therapy of infections in the hospitalized patients at Siriraj Hospital.