There have been rare reports of immune-mediated necrotizing myopathy (IMNM), an autoimmune myopathy, associated with statin use. IMNM is characterized by: proximal muscle weakness and elevated serum creatine kinase, which persist despite discontinuation of statin treatment; muscle biopsy showing necrotizing myopathy without significant inflammation; improvement with immunosuppressive agents.

All patients starting therapy with JUVISYNC, or whose dose of JUVISYNC is being increased, should be advised of the risk of myopathy, including rhabdomyolysis, and told to report promptly any unexplained muscle pain, tenderness or weakness particularly if accompanied by malaise or fever or if muscle signs and symptoms persist after discontinuing JUVISYNC. JUVISYNC therapy should be discontinued immediately if myopathy is diagnosed or suspected. In most cases, muscle symptoms and CK increases resolved when treatment was promptly discontinued. Periodic CK determinations may be considered in patients starting therapy with JUVISYNC or whose dose is being increased, but there is no assurance that such monitoring will prevent myopathy.

Many of the patients who have developed rhabdomyolysis on therapy with simvastatin have had complicated medical histories, including renal impairment usually as a consequence of long-standing diabetes mellitus. Such patients merit closer monitoring. JUVISYNC therapy should be discontinued if markedly elevated CPK levels occur or myopathy is diagnosed or suspected. JUVISYNC therapy should also be temporarily withheld in any patient experiencing an acute or serious condition predisposing to the development of renal failure secondary to rhabdomyolysis, e.g., sepsis; hypotension; major surgery; trauma; severe metabolic, endocrine, or electrolyte disorders; or uncontrolled epilepsy.

Drug Interactions

The risk of myopathy and rhabdomyolysis is increased by high levels of statin activity in plasma. Simvastatin is metabolized by the cytochrome P450 isoform 3A4. Certain drugs which inhibit this metabolic pathway can raise the plasma levels of simvastatin and may increase the risk of myopathy. These include itraconazole, ketoconazole, posaconazole, and voriconazole, the macrolide antibiotics erythromycin and clarithromycin, the ketolide antibiotic telithromycin, HIV protease inhibitors, boceprevir, telaprevir, the antidepressant nefazodone, and grapefruit juice [see Clinical Pharmacology (12.3)]. Combination of these drugs with JUVISYNC is contraindicated. If short-term treatment with strong CYP3A4 inhibitors is unavoidable, therapy with JUVISYNC must be suspended during the course of treatment. [See Contraindications (4); Drug Interactions (7.1).]

The combined use of JUVISYNC with gemfibrozil, cyclosporine, or danazol is contraindicated [see Contraindications (4); Drug Interactions (7.1, 7.2)].

Caution should be used when prescribing other fibrates with JUVISYNC, as these agents can cause myopathy when given alone and the risk is increased when they are coadministered [see Drug Interactions (7.2)].

Cases of myopathy, including rhabdomyolysis, have been reported with simvastatin coadministered with colchicine, and caution should be exercised when prescribing JUVISYNC with colchicine [see D