Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as simvastatin. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Emtricitabine; Tenofovir disoproxil fumarate: Caution is advised when administering tenofovir, PMPA, a P-glycoprotein (P-gp) substrate, concurrently with inhibitors of P-gp, such as simvastatin. Coadministration may result in increased absorption of tenofovir. Monitor for tenofovir-associated adverse reactions.
Erlotinib: Concomitant use of erlotinib and HMG-coA reductase inhibitors (statins) may increase the risk for statin-induced myopathy. Myopathy and rhabdomyolysis has been observed rarely with concurrent use of statins and erlotinib during post-market use. The mechanism for this interaction is not known. Use erlotinib and statins together with caution and monitor for signs or symptoms of statin-related adverse events including myopathy (e.g., muscle pain or weakness) and rhabdomyolysis (e.g., nausea/vomiting, dark colored urine).
Erythromycin: Erythromycin is contraindicated during simvastatin therapy. Erythromycin potently inhibits the metabolism of simvastatin via the CYP3A4 isoenzyme and increases the risk of myopathy and rhabdomyolysis. According to the manufacturer, if no alternative to a short course of erythromycin therapy is available, therapy with simvastatin must be suspended during the course of erythromycin treatment. There are no known adverse effects with short-term discontinuation of simvastatin.
Erythromycin; Sulfisoxazole: Erythromycin is contraindicated during simvastatin therapy. Erythromycin potently inhibits the metabolism of simvastatin via the CYP3A4 isoenzyme and increases the risk of myopathy and rhabdomyolysis. According to the manufacturer, if no alternative to a short course of erythromycin therapy is available, therapy with simvastatin must be suspended during the course of erythromycin treatment. There are no known adverse effects with short-term discontinuation of simvastatin.
Eslicarbazepine: In vivo studies suggest eslicarbazepine is an inducer of CYP3A4. Coadministration of CYP3A4 substrates, such as simvastatin, may result in decreased serum concentrations of the substrate. Monitor for decreased efficacy of simvastatin if coadministered with eslicarbazepine. Adjust the dose of simvastatin if clinically significant alterations in serum lipds are noted.
Esomeprazole: Simvastatin is a HMG-CoA reductase inhibitor (statin) recognized as a substrate and inhibitor of the P-glycoprotein (P-gp) transport system. Likewise, studies show that lansoprazole, omeprazole, and pantoprazole are also substrates and inhibitors of P-gp. Due to competitive inhibition of the P-gp transport system, coadministration may lead to increased intestinal absorption and/or decreased hepatic excretion of either product. The resulting increased drug bioavailability could lead to increased adverse events, including serious myopathies in the case of higher than normal statin plasma concentrations. For example, P-gp inhibition was suspected in a case report involving a patient presenting to the emergency room with rhabdomyolysis, causing third-degree AV block. The patient's medication history included atorvastatin (> 1 year history), esomeprazole (6-week history), and clarithromycin (500 mg x 3 doses p |
