Protease inhibitor-induced nausea and vomiting is attenuated by a peripherally acting, opioid-receptor antagonist in a rat model

Abstract

Abstract Background Protease inhibitors such as ritonavir can cause nausea and vomiting which is the most common reason for discontinuation. Rats react to nauseous and emetic stimuli by increasing their oral intake of non-nutritive substances like kaolin, known as pica behavior. In this study, we evaluated the effects of methylnaltrexone, a peripherally acting mu-opioid receptor antagonist that does not affect analgesia, on ritonavir-induced nausea and vomiting in a rat pica model. Results We observed that 24 to 48 hr after administration of oral ritonavir 20 mg/kg, kaolin consumption increased significantly in rats (P P P Conclusion These results suggest that methylnaltrexone may have potential clinical utility in reducing nausea and vomiting in HIV patients who take ritonavir.