“COMPARATIVE STUDY OF NATURAL AND SYNTHETIC ...

Co-administration of sildenafil with ritonavir may increased sildenafil concentrations (11-fold increase in AUC) and may result in an increase in sildenfil-associated adverse events, such as hypotension, syncope, visual changes and prolonged erection. Drugs which may require a dose increase when coadministered with ritonavir: methadone, atovaquone. ................
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