Case 5: Antiretrovirals and Statins

Question | Discussion | References | CME Credit

You answered:

	Discontinuation of efavirenz most likely caused simvastatin-induced rhabdomyolysis and renal failure. Stopping efavirenz would lead to normalization of previously induced cytochrome P450 3A4 isozymes, thus leading to a dramatic increase in blood levels of simvastatin.

This answer is incorrect. Although efavirenz has been shown to decrease levels of simvastatin by 60% due to induction of cytochrome P450 3A4 enzymes, discontinuing efavirenz would not likely dramatically elevate simvastatin plasma levels.

Choose another answer:

	Tenofovir causes a marked increase in the intracellular levels of simvastatin. Thus this combination of medications likely triggered statin-induced acute rhabdomyolysis and renal failure. This combination of tenofovir and a statin drug should be avoided in all patients.
	The patient's acute renal failure is most likely caused by tenofovir. Although the patient has a clinical presentation that suggests a diagnosis of acute rhabdomyolysis, this diagnosis could not explain the development of renal failure.
	The patient's clinical presentation is best explained by drug-induced rhabdomyolysis and acute renal failure caused by elevated blood levels of simvastatin. The increased simvastatin levels resulted from co-administration of simvastatin with lopinavir-ritonavir.

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