Drug interactions between bosentan and Viagra
| Results for the following 2 drugs: |
|---|
| bosentan |
| Viagra (sildenafil) |
Interactions between your selected drugs
sildenafil ↔ bosentan
Applies to:Viagra (sildenafil) and bosentan
MONITOR: Coadministration of bosentan and sildenafil may result in increased bosentan plasma concentrations and decreased sildenafil plasma concentrations. The mechanism is sildenafil inhibition of bosentan metabolism via CYP450 3A4 and 2C9, and bosentan induction of sildenafil metabolism via these same isoenzymes. In healthy subjects, coadministration of multiple doses of bosentan (125 mg twice a day) and sildenafil (80 mg three times a day) resulted in a 50% increase in bosentan systemic exposure (AUC) and a 63% reduction of sildenafil systemic exposure. Bosentan peak plasma concentration (Cmax) increased by 42% and sildenafil Cmax decreased by 55%. The combination did not lead to clinically significant changes in blood pressure, supine or standing.
MANAGEMENT: No dosage adjustment of either drug is necessary, whether sildenafil is used for the treatment of pulmonary arterial hypertension or erectile dysfunction. However, the possibility of prolonged and/or increased pharmacologic effects of bosentan, including serious adverse effects such as hepatotoxicity, should be considered. Patients should be advised to notify their physician if they experience signs and symptoms of hepatotoxicity such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, and jaundice.
See also...
Drug Interaction Classification
The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
| Major | Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. |
| Moderate | Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. |
| Minor | Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. |
Do not stop taking any medications without consulting your healthcare provider.
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