Effectiveness and Safety of Generic Formulation of Meropenem (Penem®®®®®) for Treatment of Infections at Siriraj Hospital
Nasikarn Angkasekwinai MD*, Peerawong Werarak MD*, Sasima Tongsai PhD*, Visanu Thamlikitkul MD*
Affiliation : * Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hopital, Mahidol University, Bangkok, Thailand
Objective : generic meropenem (Penem®) has been available and was substituted for original meropenem in Siriraj Hospital,
but its effectiveness and safety for treatment of infection in clinical setting are the main concern.
Material and Method: From July 2007 to July 2010, hospitalized patients aged 18 or older who received meropenem for at
least 48 hours were identified retrospectively from the pharmacy database of Siriraj Hospital. 260 patients per group were
required to demonstrate non-inferiority of generic meropenem (Penem®) versus original meropenem in term of overall
favorable outcome.
Results : 275 and 273 patients receiving original and generic meropenem were enrolled and analyzed. Overall favorable
outcome and overall mortality were comparable between generic and original group (72.5% vs. 65.8%, p = 0.108; 38.6%
vs. 39.3%, p = 0.918, respectively). No significant difference of adverse effect was found between two groups. The non-
inferiority test indicated that the clinical outcome and overall mortality of the generic meropenem were non-inferior to the
original meropenem (p < 0.001, p = 0.005, respectively). The independent factors associated with unfavorable outcome were
previous use of an antibiotic, having respiratory tract infection, receiving lower dose and shorter duration of antibiotic. The
independent factors associated with the overall mortality were underlying pulmonary disease, previous use of antibiotic,
having respiratory tract or catheter related blood stream infection. Treatment with either generic or original meropenem did
not relate to unfavorable outcome (p = 0.320) or overall mortality (p = 0.640).
Conclusion : Generic meropenem (Penem®) was not inferior to original meropenem for therapy of infections in the hospitalized
patients at Siriraj Hospital.
Keywords : Meropenem, Original, Generic, Non-inferiority, Efficacy
