September 17, 2012 – The Pharmacovigilance Program at the BC Centre for Excellence in HIV/AIDS has received reports of patients seeing nevirapine 400 mg XR (extended release) tablets or tablet fragments in their feces (stools). In BC, approximately 4% of patients treated with nevirapine XR have reported seeing tablet remnants in their stool.

Nevirapine 400 mg XR tablets are formulated in a non-digestible cellulose-based matrix, with the drug dispersed throughout the matrix. When tablets are swallowed, nevirapine is released into the gastrointestinal tract and absorbed into the body and the inactive tablet matrix is eliminated in the feces. Softened tablet remnants may sometimes resemble “whole” tablets, but laboratory testing has shown that the remnants are primarily inactive ingredients – the nevirapine dose has been released. The manufacturer acknowledges that reports of nevirapine XR tablet remnants in the feces have been documented among clinical trial participants and during post-marketing monitoring in other countries.

To date, there have been NO known cases of treatment failure associated with the observation of nevirapine XR tablet remnants in feces (including “whole” tablets) either in British Columbia or in the manufacturer’s global database. Quality control tests of tablet samples have confirmed that nevirapine XR tablets meet all the product specifications for dissolution performance.

There is currently no safety concern associated with the observation of nevirapine XR tablets or tablet fragments in the stool under normal physiological conditions. Nevirapine 400 mg XR tablets are available to treatment-eligible patients through the BC-CfE Drug Treatment Program.