FLUVASTATIN Drug Interactions: What You Need to Know

INTERACTIONS

• Gemfibrozil : Avoid use with fluvastatin sodium extended-release tablets. ( 7.1 )
• Cyclosporine and Fluconazole : Avoid use with fluvastatin sodium extended-release tablets. ( 7.1 )
• Fibrates, Lipid-modifying doses (≥ 1 g/day) of Niacin, and Colchicine : Consider if the benefit of concomitant use with fluvastatin sodium extended-release tablets outweighs the increased risk of myopathy and rhabdomyolysis. If concomitant use is decided, monitor patients for signs and symptoms of myopathy, particularly during initiation of therapy and during upward dose titration. ( 7.1 )
• Warfarin : Obtain an International Normalized Ratio (INR) before starting and frequently enough after initiation or discontinuation to ensure that no significant alteration in INR occurs. Once the INR is stable, monitor INR at regular intervals. ( 7.2 )
• Glyburide : Monitor blood glucose levels when fluvastatin sodium extended-release tablets are initiated. ( 7.2 )
• Phenytoin : Monitor plasma phenytoin levels when fluvastatin sodium extended-release tablets treatment is initiated. ( 7.2 )

7.1 Drug Interactions that Increase the Risk of Myopathy and Rhabdomyolysis with Fluvastatin Sodium Extended-Release Tablets Table 3 includes a list of drugs that increase the risk of myopathy and rhabdomyolysis when used concomitantly with fluvastatin and instructions for preventing or managing them <span class="opacity-50 text-xs">[see Warnings and Precautions ( 5.1 ), Clinical Pharmacology ( 12.3 )]</span> .

Table

3.

Drug Interactions That

Increase the Risk of Myopathy and Rhabdomyolysis with Fluvastatin Sodium Extended-Release Tablets Gemfibrozil Clinical impact There is an increased risk of myopathy/rhabdomyolysis when fluvastatin sodium extended-release tablets are administered with gemfibrozil Intervention Avoid concomitant use of gemfibrozil with fluvastatin sodium extended-release tablets.

Cyclosporine

Clinical impact Cyclosporine coadministration increases fluvastatin exposure. The risk of myopathy and rhabdomyolysis may be increased with concomitant use of cyclosporine with fluvastatin sodium extended-release tablets.

Intervention

Avoid concomitant use of cyclosporine with fluvastatin sodium extended-release tablets.

Fluconazole

Clinical impact Fluconazole coadministration increases fluvastatin exposure. The risk of myopathy and rhabdomyolysis may be increased with concomitant use of fluconazole with fluvastatin sodium extended-release tablets.

Intervention

Avoid concomitant use of fluconazole with fluvastatin sodium extended-release tablets.

Niacin

Clinical impact Risk of myopathy and rhabdomyolysis may be enhanced with concomitant use with lipid-modifying doses (≥ 1 g/day) of niacin with fluvastatin sodium extended-release tablets.

Intervention

Consider if the benefit of using lipid-modifying doses (≥ 1 g/day) of niacin concomitantly with fluvastatin sodium extended-release tablets outweighs the increased risk of myopathy and rhabdomyolysis. If concomitant use is decided, monitor patients for signs and symptoms of myopathy, particularly during initiation of therapy and during upward dose titration.

Fibrates

Clinical impact Fibrates may cause myopathy when given alone. The risk of myopathy and rhabdomyolysis may be increased with concomitant use of fibrates with fluvastatin sodium extended-release tablets.

Intervention

Consider if the benefit of using fibrates concomitantly with fluvastatin sodium extended-release tablets outweighs the increased risk of myopathy and rhabdomyolysis. If concomitant use is decided, monitor patients for signs and symptoms of myopathy, particularly during initiation of therapy and during upward dose titration.

Colchicine

Clinical impact Cases of myopathy and rhabdomyolysis have been reported with concomitant use of colchicine with fluvastatin.

Intervention

Consider if the benefit of using colchicine concomitantly with fluvastatin sodium extended-release tablets outweighs the increased risk of myopathy and rhabdomyolysis. If concomitant use is decided, monitor patients for signs and symptoms of myopathy, particularly during initiation of therapy and during upward dose titration.

7.2 Fluvastatin Sodium Extended-Release Tablets Effects on Other Drugs Table 4 presents fluvastatin sodium extended-release tablets’ effects on other drugs and instructions for preventing or managing them.

Table

4.

Fluvastatin Sodium

Extended-Release Tablets’ Effects on Other Drugs Warfarin Clinical impact There are postmarketing reports of clinically evident bleeding and/or increased INR in patients taking concomitant statins and warfarin. Intervention In patients taking warfarin, obtain an INR before starting fluvastatin sodium extended-release tablets and frequently enough after initiation or discontinuation to ensure that no significant alteration in INR occurs. Once the INR is stable, monitor INR at regularly recommended intervals.

Glyburide

Clinical impact Concomitant administration of fluvastatin and glyburide increased glyburide exposures [see Clinical Pharmacology ( 12.3 )] .

Intervention

Monitor blood glucose levels when fluvastatin sodium extended-release tablets are initiated.

Phenytoin

Clinical impact Concomitant administration of fluvastatin and phenytoin increased phenytoin exposures [see Clinical Pharmacology ( 12.3 )] .

Intervention

Monitor plasma phenytoin levels when fluvastatin sodium extended-release tablets are initiated.

Hypersensitivity to any component of this medication ( 4 ) Active liver disease or unexplained, persistent elevations in serum transaminases ( 4 , 5.3 ) Women who are pregnant or may become pregnant ( 4 , 8.1 ) Nursing mothers ( 4 , 8.3 )

4.1 Hypersensitivity to any Component of This Medication Fluvastatin capsules are contraindicated in patients with hypersensitivity to any component of this medication.

4.2 Active Liver Disease Fluvastatin capsules are contraindicated in patients with active liver disease or unexplained, persistent elevations in serum transaminases [ see Warnings and Precautions ( 5.3 ) ].

4.3 Pregnancy Fluvastatin capsules are contraindicated in women who are pregnant or may become pregnant. Serum cholesterol and triglycerides increase during normal pregnancy, and cholesterol or cholesterol derivatives are essential for fetal development. Fluvastatin capsules may cause fetal harm when administered to pregnant women. Atherosclerosis is a chronic process and the discontinuation of lipid-lowering drugs during pregnancy should have little impact on the outcome of long-term therapy of primary hypercholesterolemia. Fluvastatin capsules should be administered to women of childbearing age only when such patients are highly unlikely to conceive and have been informed of the potential hazards. If the patient becomes pregnant while taking this drug, fluvastatin capsules should be discontinued and the patient should be apprised of the potential hazard to the fetus [ see Use in Specific Populations ( 8.1 ) ].

4.4 Nursing Mothers Fluvastatin is secreted into the breast milk of animals and because HMG-CoA reductase inhibitors have the potential to cause serious adverse reactions in nursing infants, women who require treatment with fluvastatin capsules should be advised not to breastfeed their infants [ see Use in Specific Populations ( 8.3 ) ].

AND PRECAUTIONS Skeletal muscle effects (e.g., myopathy and rhabdomyolysis): Risks increase with advanced age (≥ 65), uncontrolled hypothyroidism, renal impairment, and combination use with cyclosporine,or gemfibrozil. Advise patients to promptly report to their physician unexplained and/or persistent muscle pain, tenderness, or weakness and discontinue fluvastatin if myopathy is diagnosed or suspected. ( 5.1 , 8.5 , 8.7 ) Patients should be advised to report promptly any symptoms of myopathy. Fluvastatin capsules therapy should be discontinued if myopathy is diagnosed or suspected ( 5.1 ) Immune-Mediated Necrotizing Myopathy (IMNM): There have been rare reports of 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; positive anti-HMG CoA reductase antibody; muscle biopsy showing necrotizing myopathy; and improvement with immunosuppressive agents. ( 5.2 ) Liver enzyme abnormalities: Persistent elevations in hepatic transaminases can occur. Check liver enzyme tests before initiating therapy and as clinically indicated thereafter ( 5.3 )

5.1 Skeletal Muscle Rhabdomyolysis with acute renal failure secondary to myoglobinuria have been reported with fluvastatin capsules and other drugs in this class. Fluvastatin capsules should be prescribed with caution in patients with predisposing factors for myopathy. These factors include advanced age (&gt; 65 years), renal impairment, and inadequately treated hypothyroidism. The risk of myopathy and/or rhabdomyolysis with statins is increased with concurrent therapy with cyclosporine, erythromycin, fibrates or niacin. Myopathy was not observed in a clinical trial in 74 patients involving patients who were treated with fluvastatin sodium together with niacin. Isolated cases of myopathy have been reported during postmarketing experience with concomitant administration of fluvastatin sodium and colchicine. No information is available on the pharmacokinetic interaction between fluvastatin sodium and colchicine. Uncomplicated myalgia has also been reported in fluvastatin sodium-treated patients [ see Adverse Reactions ( 6 ) ]. In clinical trials, uncomplicated myalgia has been observed infrequently in patients treated with fluvastatin sodium at rates indistinguishable from placebo. Myopathy, defined as muscle aching or muscle weakness in conjunction with increases in CPK values to greater than 10 times the upper limit of normal, was &lt; 0.1% in fluvastatin clinical trials. Myopathy should be considered in any patient with diffuse myalgias, muscle tenderness or weakness, and/or marked elevation of CPK. All patients should be advised to promptly report to their physician unexplained muscle pain, tenderness, or weakness, particularly if accompanied by malaise or fever or if muscle signs and symptoms persist after discontinuing fluvastatin. Fluvastatin sodium therapy should be discontinued if markedly elevated CPK levels occur or myopathy is diagnosed or suspected. Fluvastatin sodium 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.

5.2 Immune-Mediated Necrotizing Myopathy 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; positive anti-HMG CoA reductase antibody; muscle biopsy showing necrotizing myopathy; and improvement with immunosuppressive agents. Additional neuromuscular and serologic testing may be necessary. Treatment with immunosuppressive agents may be required. Consider risk of IMNM carefully prior to initiation of a different statin. If therapy is initiated with a different statin, monitor for signs and symptoms of IMNM.

5.3 Liver Enzymes Increases in serum transaminases (aspartate aminotransferase [AST]/serum glutamic-oxaloacetic transaminase, or alanine aminotransferase [ALT]/serum glutamic-pyruvic transaminase) have been reported with HMG-CoA reductase inhibitors, including fluvastatin sodium. In most cases, the elevations were transient and resolved or improved on continued therapy or after a brief interruption in therapy.

Approximately

1.1% of patients treated with fluvastatin capsules in worldwide trials developed dose-related, persistent elevations of serum transaminase levels to more than 3 times the upper limit of normal. Fourteen of these patients (0.6%) were discontinued from therapy. In all clinical trials, a total of 33/2969 patients (1.1%) had persistent transaminase elevations with an average fluvastatin sodium exposure of approximately 71.2 weeks; 19 of these patients (0.6%) were discontinued. The majority of patients with these abnormal biochemical findings were asymptomatic. In a pooled analysis of all placebo-controlled studies in which fluvastatin capsules were used, persistent transaminase elevations (> 3 times the upper limit of normal [ULN] on two consecutive weekly measurements) occurred in 0.2%, 1.5%, and 2.7% of patients treated with daily doses of 20, 40, and 80 mg (titrated to 40 mg twice daily) fluvastatin capsules, respectively. Ninety-one percent of the cases of persistent liver function test abnormalities (20 of 22 patients) occurred within 12 weeks of therapy and in all patients with persistent liver function test abnormalities there was an abnormal liver function test present at baseline or by Week 8. In the pooled analysis of the 24 week controlled trials, persistent transaminase elevation occurred in 1.8% and 4.9% of patients treated with fluvastatin capsules, 40 mg and fluvastatin capsules, 40 mg twice daily, respectively. It is recommended that liver enzyme tests be performed prior to the initiation of fluvastatin sodium, and if signs or symptoms of liver injury occur. There have been rare postmarketing reports of fatal and non-fatal hepatic failure in patients taking statins, including fluvastatin. If serious liver injury with clinical symptoms and/or hyperbilirubinemia or jaundice occurs during treatment with fluvastatin sodium, promptly interrupt therapy. If an alternate etiology is not found do not restart fluvastatin sodium. In very rare cases, possibly drug-related hepatitis was observed that resolved upon discontinuation of treatment. 1 Active liver disease or unexplained serum transaminase elevations are contraindications to the use of fluvastatin sodium [ see Contraindications ( 4 ) and Warnings and Precautions ( 5.3 ) ]. Caution should be exercised when fluvastatin sodium is administered to patients with a history of liver disease or heavy alcohol ingestion [ see Clinical Pharmacology ( 12.3 ) ]. Such patients should be closely monitored.

5.4 Endocrine Effects Increases in HbA1c and fasting serum glucose levels have been reported with HMG-CoA reductase inhibitors, including fluvastatin sodium. Statins interfere with cholesterol synthesis and lower circulating cholesterol levels and, as such, might theoretically blunt adrenal or gonadal steroid hormone production. Fluvastatin sodium exhibited no effect upon non-stimulated cortisol levels and demonstrated no effect upon thyroid metabolism as assessed by measurement of thyroid stimulating hormone (TSH). Small declines in total serum testosterone have been noted in treated groups, but no commensurate elevation in LH occurred, suggesting that the observation was not due to a direct effect upon testosterone production. No effect upon FSH in males was noted. Due to the limited number of premenopausal females studied to date, no conclusions regarding the effect of fluvastatin sodium upon female sex hormones may be made. Two clinical studies in patients receiving fluvastatin at doses up to 80 mg daily for periods of 24 to 28 weeks demonstrated no effect of treatment upon the adrenal response to ACTH stimulation. A clinical study evaluated the effect of fluvastatin at doses up to 80 mg daily for 28 weeks upon the gonadal response to HCG stimulation. Although the mean total testosterone response was significantly reduced (p &lt; 0.05) relative to baseline in the 80 mg group, it was not significant in comparison to the changes noted in groups receiving either 40 mg of fluvastatin or placebo. Patients treated with fluvastatin sodium who develop clinical evidence of endocrine dysfunction should be evaluated appropriately. Caution should be exercised if a statin or other agent used to lower cholesterol levels is administered to patients receiving other drugs (e.g., ketoconazole, spironolactone, cimetidine) that may decrease the levels of endogenous steroid hormones.

5.5 CNS Toxicity CNS effects, as evidenced by decreased activity, ataxia, loss of righting reflex, and ptosis were seen in the following animal studies: the 18 month mouse carcinogenicity study at 50 mg/kg/day, the 6 month dog study at 36 mg/kg/day, the 6 month hamster study at 40 mg/kg/day, and in acute, high-dose studies in rats and hamsters (50 mg/kg), rabbits (300 mg/kg) and mice (1500 mg/kg). CNS toxicity in the acute high-dose studies was characterized (in mice) by conspicuous vacuolation in the ventral white columns of the spinal cord at a dose of 5000 mg/kg and (in rats) by edema with separation of myelinated fibers of the ventral spinal tracts and sciatic nerve at a dose of 1500 mg/kg. CNS toxicity, characterized by periaxonal vacuolation, was observed in the medulla of dogs that died after treatment for 5 weeks with 48 mg/kg/day; this finding was not observed in the remaining dogs when the dose level was lowered to 36 mg/kg/day. CNS vascular lesions, characterized by perivascular hemorrhages, edema, and mononuclear cell infiltration of perivascular spaces, have been observed in dogs treated with other members of this drug class. No CNS lesions have been observed after chronic treatment for up to 2 years with fluvastatin in the mouse (at doses up to 350 mg/kg/day), rat (up to 24 mg/kg/day), or dog (up to 16 mg/kg/day). Prominent bilateral posterior Y suture lines in the ocular lens were seen in dogs after treatment with 1, 8, and 16 mg/kg/day for 2 years.