Saquinavir valproic acid

Tipranavir both inhibits and induces the CYP3A4 system. When used in combination with ritonavir, its net effect is inhibition. Tipranavir also induces P-glycoprotein transporter and thus may alter the disposition of many other drugs (Table 49-4). Concurrent administration of tipranavir with fosamprenavir or saquinavir should be avoided owing to decreased blood levels of the latter drugs. Tipranavir/ritonavir may also decrease serum levels of valproic acid and omeprazole. Levels of lovastatin, simvastatin, atorvastatin, and rosuvastatin may be increased, increasing the risk for rhabdomyolysis and myopathy. 

Efavirenz levels were not altered by valproic acid in one study in mV-positive patients, and valproic acid levels were not different to those in a control group not taking efavirenz. However, one patient had a marked decrease in valproate levels after starting efavirenz. A case of hepatotoxicity has occurred in a patient taking valproic acid with nevirapine and saquinavir/ritonavir. 

A case of valproate-associated hepatotoxicity occurred in a 51-year-old man about 3 weeks after he started nevirapine 200 mg twice daily, saquinavir/ritonavir 400/400 mg twice daily, and stavudine. Serum valproic acid levels remained therapeutic. ... 

---