"June 9, 2011 -- The FDA today tightened its rules on who should take the highest approved dose of the statin drug simvastatin.
Simvastatin, which lowers LDL "bad" cholesterol, is sold under the brand name Zocor and as a generic drug. "...
SIMCOR should not be substituted for equivalent doses of immediate-release (crystalline) niacin. For patients switching from immediate-release niacin to SIMCOR, therapy with SIMCOR should be initiated at 500/20 mg and appropriately titrated to the desired therapeutic response. Patients already taking simvastatin 20-40 mg who need additional management of their lipid levels may be started on a SIMCOR dose of 500/40 mg once daily at bedtime. Doses of SIMCOR greater than 2000/40 mg are not recommended.
Mortality and Coronary Heart Disease Morbidity
The Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health Outcomes (AIM-HIGH) trial was a randomized placebo-controlled trial of 3414 patients with stable, previously diagnosed cardiovascular disease. Mean baseline lipid levels were LDL-C 74 mg/dL, HDL-C 35 mg/dL, non-HDL-C 111 mg/dL and median triglyceride level of 163-177 mg/dL. Ninety-four percent of patients were on background statin therapy prior to entering the trial. All participants received simvastatin, 40 to 80 mg per day, plus ezetimibe 10 mg per day if needed, to maintain an LDL-C level of 40-80 mg/dL, and were randomized to receive niacin extended-release tablets 1500-2000 mg/day (n=1718) or matching placebo (niacin immediate-release tablets, 100-150 mg, n=1696).
On-treatment lipid changes at two years for LDL-C were -12.0% for the simvastatin plus niacin extended-release group and -5.5% for the simvastatin plus placebo group. HDL-C increased by 25.0% to 42 mg/dL in the simvastatin plus niacin extended-release group and by 9.8% to 38 mg/dL in the simvastatin plus placebo group (P < 0.001). Triglyceride levels decreased by 28.6% in the simvastatin plus niacin immediate-release group and by 8.1% in the simvastatin plus placebo group.
The primary outcome was an ITT composite of the first study occurrence of coronary heart disease death, nonfatal myocardial infarction, ischemic stroke, hospitalization for acute coronary syndrome or symptom-driven coronary or cerebral revascularization procedures. The trial was stopped after a mean follow-up period of 3 years owing to a lack of efficacy. The primary outcome occurred in 282 patients in the simvastatin plus niacin extended-release group (16.4%) and in 274 patients in the simvastatin plus placebo group (16.2%) (HR 1.02 [95% CI, 0.87-1.21], P=0.79.
In an ITT analysis, there were 42 cases of first occurrence of ischemic stroke reported, 27 (1.6%) in the simvastatin plus niacin extended-release group and 15 (0.9%) in the simvastatin plus placebo group, a non-statistically significant result (HR 1.79, [95%CI = 0.95-3.36], p=0.071). The on-treatment ischemic stroke events were 19 for the simvastatin plus niacin extended-release group and 15 for the simvastatin plus placebo group [see ADVERSE REACTIONS].
Simvastatin occasionally causes myopathy manifested as muscle pain, tenderness or weakness with creatine kinase (CK) above ten times the upper limit of normal (ULN). Myopathy sometimes takes the form of rhabdomyolysis with or without acute renal failure secondary to myoglobinuria, and rare fatalities have occurred. The risk of myopathy is increased by high levels of HMG-CoA reductase inhibitory activity in plasma. Predisposing factors for myopathy include advanced age ( ≥ 65 years), female gender, uncontrolled hypothyroidism, and renal impairment.
The risk of myopathy/rhabdomyolysis is dose related. In a clinical trial database in which 41,413 patients were treated with simvastatin with 24,747 (approximately 60%) of whom were enrolled in studies with a median follow-up of at least 4 years, the incidence of myopathy was approximately 0.03% and 0.08% at 20 and 40 mg/day, respectively. The incidence of myopathy with 80 mg (0.61%) was disproportionately higher than that observed at the lower doses. In these trials, patients were carefully monitored and some interacting medicinal products were excluded.
In a clinical trial in which 12,064 patients with a history of myocardial infarction were treated with ZOCOR (mean follow-up 6.7 years), the incidence of myopathy (defined as unexplained muscle weakness or pain with a serum creatine kinase [CK] > 10 times upper limit of normal [ULN]) in patients on 80 mg/day was approximately 0.9% compared with 0.02% for patients on 20 mg/day; the incidence of rhabdomyolysis (defined as myopathy with a CK > 40 times ULN) was approximately 0.4% in patients on 80 mg/day compared with 0% for patients on 20 mg/day. The incidence of myopathy, including rhabdomyolysis, was highest during the first year and then notably decreased during the subsequent years of treatment. In this trial, patients were carefully monitored and some interacting medicinal products were excluded.
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 SIMCOR, or whose dose of SIMCOR 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 SIMCOR. SIMCOR 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 SIMCOR 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 insufficiency usually as a consequence of long-standing diabetes mellitus. Such patients merit closer monitoring. SIMCOR therapy should be discontinued if markedly elevated CPK levels occur or myopathy is diagnosed or suspected. SIMCOR 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.
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, and posaconazole, the macrolide antibiotics erythromycin and clarithromycin, and the ketolide antibiotic telithromycin, HIV protease inhibitors, boceprevir, telaprevir, the antidepressant nefazodone, or large quantities of grapefruit juice ( > 1 quart daily), and combination of these drugs with SIMCOR is contraindicated. If treatment with itraconazole, ketoconazole, posaconazole, erythromycin, clarithromycin or telithromycin is unavoidable, therapy with SIMCOR must be suspended during the course of treatment [see CONTRAINDICATIONS and DRUG INTERACTIONS]. In vitro studies have demonstrated a potential for voriconazole to inhibit the metabolism of simvastatin. Adjustment of the SIMCOR dose may be needed to reduce the risk of myopathy/rhabdomyolysis if voriconazole must be used concomitantly with simvastatin [see DRUG INTERACTIONS].
The combined use of SIMCOR with verapamil or diltiazem is contraindicated, because dosages of simvastatin are not to exceed 10 mg when these drugs are co-administered and all doses of SIMCOR contain simvastatin in excess of 10 mg [see CONTRAINDICATIONS and DRUG INTERACTIONS].
The combined use of SIMCOR with drugs that cause myopathy/rhabdomyolysis when given alone, such as fibrates, should be avoided [see DRUG INTERACTIONS].
Cases of myopathy, including rhabdomyolysis, have been reported with simvastatin coadministered with colchicine, and caution should be exercised when prescribing SIMCOR with colchicine [see DRUG INTERACTIONS].
The benefits of the combined use of SIMCOR with amlodipine or ranolazine should be carefully weighed against the potential risks of combination [see DRUG INTERACTIONS]. Periodic CK determinations may be considered in patients starting therapy with or increasing the dose of these agents, but there is no assurance that such monitoring will prevent myopathy.
Cases of myopathy, including rhabdomyolysis, have been observed with simvastatin coadministered with lipid-modifying doses ( ≥ 1 g/day niacin) of niacin-containing products. In an ongoing, double-blind, randomized cardiovascular outcomes trial, an independent safety monitoring committee identified that the incidence of myopathy is higher in Chinese compared with non-Chinese patients taking simvastatin 40 mg coadministered with lipid modifying doses of a niacin-containing product. Caution should be used when prescribing SIMCOR in doses that exceed 1000/20 mg/day to Chinese patients. It is unknown if the risk for myopathy with coadministration of simvastatin with lipid modifying doses of niacin-containing products observed in Chinese patients applies to other Asian patients [see DOSAGE AND ADMINISTRATION].
Table 3 : Drug Interactions Associated with Increased
Risk of Myopathy/Rhabdomyolysis
|Interacting Agents||Prescribing Recommendations|
|Strong CYP3A4 inhibitors, e.g.,
HIV protease inhibitors
|Contraindicated with SIMCOR|
|Do not exceed 1000/20 mg SIMCOR daily|
|Grapefruit juice||Avoid large quantities of grapefruit juice ( > 1 quart daily)|
Myopathy and/or rhabdomyolysis have been reported when simvastatin is used in combination with lipid-altering doses ( ≥ 1 gram/day) of niacin. Physicians contemplating the use of SIMCOR, a combination of simvastatin and niacin extended-release (NIASPAN), should weigh the potential benefits and risks, and should carefully monitor for any signs and symptoms of muscle pain, tenderness, or weakness, particularly during the initial month of treatment or during any period of upward dosage titration of either drug. Periodic determination of serum creatine kinase (CK) determinations may be considered in such situations, but there is no assurance that such monitoring will prevent myopathy.
Patients starting therapy with SIMCOR should be advised of the risk of myopathy, and told to report promptly unexplained muscle pain, tenderness, or weakness. A CK level above ten times the upper limit of normal (ULN) in a patient with unexplained muscle symptoms indicates myopathy. SIMCOR therapy should be discontinued if myopathy is diagnosed or suspected.
In patients with complicated medical histories predisposing to rhabdomyolysis, such as renal insufficiency, dose escalation requires caution. Also, as there are no known adverse consequences of brief interruption of therapy, treatment with SIMCOR should be stopped for a few days before elective major surgery and when any major acute medical or surgical condition supervenes (e.g., sepsis, hypotension, dehydration, major surgery, trauma, severe metabolic, endocrine, and electrolyte disorders, or uncontrolled seizures).
Cases of severe hepatic toxicity, including fulminant hepatic necrosis, have occurred in patients who have substituted sustained-release (modified-release, timed-release) niacin products for immediate-release (crystalline) niacin at equivalent doses. Patients previously receiving niacin products other than niacin extended-release (NIASPAN) should be started on SIMCOR at the lowest recommended starting dose [see DOSAGE AND ADMINISTRATION].
SIMCOR should be used with caution in patients who consume substantial quantities of alcohol and/or have a past history of liver disease. Active liver disease or unexplained transaminase elevations are contraindications to the use of SIMCOR [see CONTRAINDICATIONS].
Niacin extended-release (NIASPAN) and simvastatin can cause abnormal liver tests. In a simvastatin-controlled, 24 week study with SIMCOR in 641 patients, there were no persistent increases (to more than 3x the ULN) in serum transaminases. In three placebo-controlled clinical studies of niacin extended-release, patients with normal serum transaminases levels at baseline did not experience any transaminase elevations greater than 3x the ULN. Persistent increases (to more than 3x the ULN) in serum transaminases have occurred in approximately 1% of patients who received simvastatin in clinical studies. When drug treatment was interrupted or discontinued in these patients, the transaminases levels usually fell slowly to pretreatment levels. The increases were not associated with jaundice or other clinical signs or symptoms. There was no evidence of hypersensitivity.
It is recommended that liver enzyme tests be obtained prior to initiating therapy with SIMCOR and repeated as clinically indicated. There have been rare postmarketing reports of fatal and nonfatal hepatic failure in patients taking statins, including simvastatin. If serious liver injury with clinical symptoms and/or hyperbilirubinemia or jaundice occurs during treatment with SIMCOR, promptly interrupt therapy. If an alternate etiology is not found do not restart SIMCOR. Note that ALT may emanate from muscle, therefore ALT rising with CK may indicate myopathy.
Increase in Blood Glucose
Niacin treatment can increase fasting blood glucose. In a simvastatin-controlled, 24-week study with SIMCOR the change from baseline in glycosylated hemoglobin levels was 0.2% for SIMCOR-treated patients and 0.2% for simvastatin-treated patients. Diabetic or potentially diabetic patients should be observed closely during treatment with SIMCOR, particularly during the first few months of therapy. Adjustment of diet and/or hypoglycemic therapy or discontinuation of SIMCOR may be necessary.
Reduction in platelet count
Niacin can reduce platelet count. In a simvastatin-controlled, 24week study with SIMCOR the mean percent change from baseline for patients treated with 2000/40 mg daily was -5.6%.
Increase in ProthrombinTime (PT)
Niacin can cause small increases in PT. In a simvastatincontrolled, 24-week study with SIMCOR this effect was not seen.
Increase in Uric Acid
Elevated uric acid levels have occurred with niacin therapy. In a simvastatin-controlled, 24-week study with SIMCOR this effect was not seen. Nevertheless, in patients predisposed to gout, SIMCOR therapy should be used with caution.
Decrease in Phosphorus
Small dose-related reductions in phosphorous levels were seen in clinical studies with niacin. In a simvastatin-controlled, 24-week study with SIMCOR this effect was not seen.
Increases in HbA1c and fasting serum glucose levels have been reported with HMG-CoA reductase inhibitors, including simvastatin.
Carcinogenesis, Mutagenesis, Impairment of Fertility
No studies have been conducted with SIMCOR regarding carcinogenesis, mutagenesis, or impairment of fertility.
Niacin, administered to mice for a lifetime as a 1% solution in drinking water, was not carcinogenic. The mice in this study received approximately 6 to 8 times a human dose of 3000 mg/day as determined on a mg/m² basis. Niacin was negative for mutagenicity in the Ames test. No studies on impairment of fertility have been performed.
In a 72-week carcinogenicity study, mice were administered daily doses of simvastatin of 25, 100, and 400 mg/kg body weight, which resulted in mean plasma drug levels approximately 1, 4, and 8 times higher than the mean human plasma drug level, respectively (as total inhibitory activity based on AUC) after an 80-mg oral dose. Liver carcinomas were significantly increased in high-dose females and mid- and high-dose males with a maximum incidence of 90% in males. The incidence of adenomas of the liver was significantly increased in mid- and high-dose females. Drug treatment also significantly increased the incidence of lung adenomas in mid- and high-dose males and females. Adenomas of the Harderian gland (a gland of the eye of rodents) were significantly higher in high-dose mice than in controls. No evidence of a tumorigenic effect was observed at 25 mg/kg/day.
In a separate 92-week carcinogenicity study in mice at doses up to 25 mg/kg/day, no evidence of a tumorigenic effect was observed (mean plasma drug levels were 1 times higher than humans given 80 mg simvastatin as measured by AUC). In a two-year study in rats at 25 mg/kg/day, there was a statistically significant increase in the incidence of thyroid follicular adenomas in female rats exposed to approximately 11 times higher levels of simvastatin than in humans given 80 mg simvastatin (as measured by AUC). A second two-year rat carcinogenicity study with doses of 50 and 100 mg/kg/day produced hepatocellular adenomas and carcinomas (in female rats at both doses and in males at 100 mg/kg/day). Thyroid follicular cell adenomas were increased in males and females at both doses; thyroid follicular cell carcinomas were increased in females at 100 mg/kg/day. The increased incidence of thyroid neoplasms appears to be consistent with findings from other HMG-CoA reductase inhibitors. These treatment levels represented plasma drug levels (AUC) of approximately 7 and 15 times (males) and 22 and 25 times (females) the mean human plasma drug exposure after an 80 milligram daily dose. No evidence of mutagenicity was observed in a microbial mutagenicity (Ames) test with or without rat or mouse liver metabolic activation. In addition, no evidence of damage to genetic material was noted in an in vitro alkaline elution assay using rat hepatocytes, a V-79 mammalian cell forward mutation study, an in vitro chromosome aberration study in CHO cells, or an in vivo chromosomal aberration assay in mouse bone marrow. There was decreased fertility in male rats treated with simvastatin for 34 weeks at 25 mg/kg body weight (4 times the maximum human exposure level, based on AUC, in patients receiving 80 mg/day); however, this effect was not observed during a subsequent fertility study in which simvastatin was administered at this same dose level to male rats for 11 weeks (the entire cycle of spermatogenesis including epididymal maturation). No microscopic changes were observed in the testes of rats from either study. At 180 mg/kg/day, (which produces exposure levels 22 times higher than those in humans taking 80 mg/day based on surface area, mg/m²), seminiferous tubule degeneration (necrosis and loss of spermatogenic epithelium) was observed. In dogs, there was drug-related testicular atrophy, decreased spermatogenesis, spermatocytic degeneration and giant cell formation at 10 mg/kg/day, (approximately 2 times the human exposure, based on AUC, at 80 mg/day). The clinical significance of these findings is unclear.
Use In Specific Populations
Pregnancy Category X – [see CONTRAINDICATIONS]
SIMCOR is contraindicated in women who are or may become pregnant. Lipid lowering drugs offer no benefit during pregnancy, because cholesterol and cholesterol derivatives are needed for normal fetal development. Serum cholesterol and triglycerides increase during normal pregnancy. Atherosclerosis is a chronic process, and discontinuation of lipid-lowering drugs during pregnancy should have little impact on long-term outcomes of primary hypercholesterolemia therapy. There are no adequate and well-controlled studies of SIMCOR use during pregnancy; however, there are rare reports of congenital anomalies in infants exposed to HMG-CoA reductase inhibitors in utero. Animal reproduction studies of simvastatin in rats and rabbits showed no evidence of teratogenicity. SIMCOR may cause fetal harm when administered to a pregnant woman. If SIMCOR is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
SIMCOR contains simvastatin (a HMG-CoA reductase inhibitor) and niacin (nicotinic acid). There are rare reports of congenital anomalies following intrauterine exposure to HMG-CoA reductase inhibitors. In a review of approximately 100 prospectively followed pregnancies in women exposed to simvastatin or another structurally related HMG-CoA reductase inhibitor, the incidences of congenital anomalies, spontaneous abortions, and fetal deaths/stillbirths did not exceed those expected in the general population. However, the study was only able to exclude a 3- to 4-fold increased risk of congenital anomalies over the background rate. In 89% of these cases, drug treatment was initiated prior to pregnancy and was discontinued during the first trimester when pregnancy was identified. It is not known whether niacin at doses used for lipid disorders can cause fetal harm when administered to a pregnant woman.
Simvastatin was not teratogenic in rats or rabbits at doses that resulted in 3 times the human exposure based on mg/m² surface area. However, in studies with another structurally-related HMG-CoA reductase inhibitor, skeletal malformations were observed in rats and mice. Animal reproduction studies have not been conducted with niacin.
Women of childbearing potential, who require SIMCOR treatment for a lipid disorder, should use effective contraception. Patients trying to conceive should contact their prescriber to discuss stopping SIMCOR treatment. If pregnancy occurs, SIMCOR should be immediately discontinued.
It is not known whether simvastatin is excreted into human milk; however, a small amount of another drug in this class does pass into breast milk. Niacin is excreted into human milk but the actual infant dose or infant dose as a percent of the maternal dose is not known. Because of the potential for serious adverse reactions in nursing infants, nursing mothers who require SIMCOR treatment should not breastfeed their infants. A decision should be made whether to discontinue nursing or discontinue drug, taking into account the importance of the drug to the mother [see CONTRAINDICATIONS].
The safety and effectiveness of SIMCOR in pediatric patients have not been established.
There were 281 (30.8%) patients aged 65 years and older treated with SIMCOR in Phase III clinical studies. No overall differences in safety and effectiveness were observed between these patients and younger patients, but greater sensitivity of some older individuals cannot be ruled out. A pharmacokinetic study with simvastatin showed the mean plasma level of HMG-CoA reductase inhibitory activity to be approximately 45% higher in elderly patients between 70-78 years of age compared with patients between 18-30 years of age.
Because advanced age ( ≥ 65 years) is a predisposing factor for myopathy, including rhabdomyolysis, SIMCOR should be prescribed with caution in the elderly. In a clinical trial of patients treated with simvastatin 80 mg/day, patients ≥ 65 years of age had an increased risk of myopathy, including rhabdomyolysis, compared to patients < 65 years of age [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].
Data from the clinical trials suggest that women have a greater hypolipidemic response than men at equivalent doses of niacin extended-release. No consistent gender differences in efficacy and safety were observed in SIMCOR studies.
No pharmacokinetic studies have been conducted in patients with renal impairment for SIMCOR. Caution should be exercised when SIMCOR is administered to patients with renal disease. For patients with severe renal insufficiency, SIMCOR should not be started unless the patient has already tolerated treatment with simvastatin at a dose of 10 mg or higher. Caution should be exercised when SIMCOR is administered to these patients and they should be closely monitored.
No pharmacokinetic studies have been conducted in patients with hepatic insufficiency for SIMCOR [see WARNINGS AND PRECAUTIONS].
Last reviewed on RxList: 3/7/2013
This monograph has been modified to include the generic and brand name in many instances.
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