Ritonavir Dextropropoxyphene

C7H7ClMg 6921-34-2) see Bencyclane Clomifene Dextropropoxyphene Ritonavir 7V-benzylmaleimide... 

Ritonavir decreases pethidine (meperidine) and increases norpethidine levels, which may possibly increase toxicity on long-term use. Similarly, ritonavir and other protease inhibitors increase buprenorphine levels. Ritonavir may increase the metabolism of morphine, and decrease the metabolism of dextropropoxyphene (CYP3A4 substrate) and tramadol or other CYP2D6 substrates (such as codeine). 

Ritonavir is a potent inhibitor of CYP3A4 and therefore the UK manufacturer of ritonavir contraindicates its use with dextropropoxyphene as extremely raised dextropropoxyphene levels may occur, which would increase the risk of serious respiratory depression or other serious adverse events. However, the US manufacturer only suggests that a dose decrease may be needed. ... 

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