WARNINGS
Included as part of the PRECAUTIONS section.
PRECAUTIONS
Myopathy/Rhabdomyolysis
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 statin activity in plasma. Predisposing factors for myopathy include
advanced age ( ≥65 years), female gender, uncontrolled hypothyroidism, and
renal impairment.
The risk of myopathy, including rhabdomyolysis, is
dose related. In a clinical trial database in which 41,413 patients were
treated with simvastatin, 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 simvastatin (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) in patients on 80 mg/day was approximately 0.4%
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.
The risk of myopathy, including rhabdomyolysis, is
greater in patients on simvastatin 80 mg compared with other statin therapies
with similar or greater LDL-C-lowering efficacy and compared with lower doses
of simvastatin. Therefore, an 80-mg dose of Simvastatin Oral Suspension should
be used only in patients who have been taking simvastatin 80 mg chronically
(e.g., for 12 months or more) without evidence of muscle toxicity [see DOSAGE
AND ADMINISTRATION, Restricted Dosing for 80 mg]. If, however, a patient who is
currently tolerating the 80-mg dose of Simvastatin Oral Suspension needs to be
initiated on an interacting drug that is contraindicated or is associated with
a dose cap for simvastatin, that patient should be switched to an alternative
statin with less potential for the drug-drug interaction. Patients should be
advised of the increased risk of myopathy, including rhabdomyolysis, and to
report promptly any unexplained muscle pain, tenderness or weakness. If
symptoms occur, treatment should be discontinued immediately. [See
WARNINGS AND PRECAUTIONS]
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 Simvastatin Oral
Suspension, or whose dose of Simvastatin Oral Suspension 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 Simvastatin Oral Suspension. Simvastatin Oral
Suspension 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 Simvastatin Oral Suspension 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. Simvastatin Oral Suspension
therapy should be discontinued if markedly elevated CPK levels occur or
myopathy is diagnosed or suspected. Simvastatin Oral Suspension 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, voriconazole,
the macrolide antibiotics erythromycin and clarithromycin, and the ketolide
antibiotic telithromycin, HIV protease inhibitors, boceprevir, telaprevir, the
antidepressant nefazodone, cobicistat-containing products, or grapefruit juice [see
CLINICAL PHARMACOLOGY]. Combination of these drugs with simvastatin is
contraindicated. If short-term treatment with strong CYP3A4 inhibitors is
unavoidable, therapy with simvastatin must be suspended during the course of
treatment. [See CONTRAINDICATIONS and DRUG INTERACTIONS]
The combined use of simvastatin with gemfibrozil,
cyclosporine, or danazol is contraindicated [see CONTRAINDICATIONS and DRUG
INTERACTIONS].
Caution should be used when prescribing other fibrates
with simvastatin, as these agents can cause myopathy when given alone and the
risk is increased when they are co-administered [see DRUG INTERACTIONS].
Cases of myopathy, including rhabdomyolysis, have been
reported with simvastatin coadministered with colchicine, and caution should be
exercised when prescribing simvastatin with colchicine [see DRUG
INTERACTIONS].
The benefits of the combined use of simvastatin with the
following drugs should be carefully weighed against the potential risks of
combinations: other lipid-lowering drugs (other fibrates, ≥1 g/day of
niacin, or, for patients with HoFH, lomitapide), amiodarone, dronedarone,
verapamil, diltiazem, amlodipine, or ranolazine [see DRUG INTERACTIONS and
Table 3 in CLINICAL PHARMACOLOGY] [also see DOSAGE AND ADMINISTRATION,
Patients with Homozygous Familial Hypercholesterolemia].
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 treating Chinese patients with simvastatin in doses exceeding 20 mg/day
coadministered with lipid-modifying doses of niacin-containing products.
Because the risk for myopathy is dose-related, Chinese patients should not
receive simvastatin 80 mg coadministered with lipid-modifying doses of
niacin-containing products. 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
DRUG INTERACTIONS].
Prescribing recommendations for interacting agents are
summarized in Table 1 [see also DOSAGE AND ADMINISTRATION, DRUG
INTERACTIONS, CLINICAL PHARMACOLOGY].
Table 1: Drug Interactions Associated with Increased
Risk of Myopathy/Rhabdomyolysis
Interacting Agents |
Prescribing Recommendations |
Strong CYP3A4 Inhibitors, e.g.: |
Contraindicated with simvastatin |
Itraconazole |
Ketoconazole |
Posaconazole |
Voriconazole |
Erythromycin |
Clarithromycin |
Telithromycin |
HIV protease inhibitors |
Boceprevir |
Telaprevir |
Nefazodone |
Cobicistat-containing products |
Gemfibrozil |
Cyclosporine |
Danazol |
Verapamil |
Do not exceed 10 mg simvastatin daily |
Diltiazem |
Dronedarone |
Amiodarone |
Do not exceed 20 mg simvastatin daily |
Amlodipine |
Ranolazine |
Lomitapide |
For patients with HoFH, do not exceed 20 mg simvastatin daily* |
Grapefruit juice |
Avoid grapefruit juice |
* For patients with HoFH who have been taking 80 mg
simvastatin chronically (e.g., for 12 months or more) without evidence of
muscle toxicity, do not exceed 40 mg simvastatin when taking lomitapide. |
Liver Dysfunction
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 transaminase 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.
In the Scandinavian Simvastatin
Survival Study (4S) [see Clinical Studies], the number of patients with
more than one transaminase elevation to >3X ULN, over the course of the
study, was not significantly different between the simvastatin and placebo
groups (14 [0.7%] vs. 12 [0.6%]). Elevated transaminases resulted in the discontinuation
of 8 patients from therapy in the simvastatin group (n=2,221) and 5 in the
placebo group (n=2,223). Of the 1,986 simvastatin treated patients in 4S with
normal liver function tests  (LFTs) at baseline, 8 (0.4%) developed
consecutive LFT elevations to >3X ULN and/or were discontinued due to
transaminase elevations during the 5.4 years (median follow-up) of the study.
Among these 8 patients, 5 initially developed these abnormalities within the
first year. All of the patients in this study received a starting dose of 20 mg
of simvastatin; 37% were titrated to 40 mg.
In 2 controlled clinical studies in 1,105 patients, the
12-month incidence of persistent hepatic transaminase elevation without regard
to drug relationship was 0.9% and 2.1% at the 40-and 80-mg dose, respectively.
No patients developed persistent liver function abnormalities following the
initial 6 months of treatment at a given dose.
It is recommended that liver function tests be
performed before the initiation of treatment, and thereafter when clinically
indicated. There have been rare postmarketing reports of fatal and
non-fatal hepatic failure in patients taking statins, including simvastatin. If
serious liver injury with clinical symptoms and/or hyperbilirubinemia or
jaundice occurs during treatment with Simvastatin Oral Suspension, promptly
interrupt therapy. If an alternate etiology is not found do not restart
Simvastatin Oral Suspension. Note that ALT may emanate from muscle, therefore
ALT rising with CK may indicate myopathy [see Endocrine Function].
The drug should be used with caution in patients who
consume substantial quantities of alcohol and/or have a past history of liver
disease. Active liver diseases or unexplained transaminase elevations are
contraindications to the use of simvastatin.
Moderate (less than 3X ULN) elevations of serum
transaminases have been reported following therapy with simvastatin. These
changes appeared soon after initiation of therapy with simvastatin, were often
transient, were not accompanied by any symptoms and did not require
interruption of treatment.
Endocrine Function
Increases in HbA1c and fasting serum glucose levels have
been reported with HMG-CoA reductase inhibitors, including simvastatin.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis,
Impairment Of Fertility
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 statins. 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
Pregnancy Category X [See CONTRAINDICATIONS]
Simvastatin Oral Suspension 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. 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 use with simvastatin during
pregnancy; however, there are rare reports of congenital anomalies in infants
exposed to statins in utero. Animal reproduction studies of simvastatin in rats
and rabbits showed no evidence of teratogenicity. Serum cholesterol and
triglycerides increase during normal pregnancy, and cholesterol or cholesterol
derivatives are essential for fetal development. Because statins decrease
cholesterol synthesis and possibly the synthesis of other biologically active
substances derived from cholesterol, simvastatin may cause fetal harm when
administered to a pregnant woman. If Simvastatin Oral Suspension 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.
There are rare reports of congenital anomalies following
intrauterine exposure to statins. In a review2 of approximately 100
prospectively followed pregnancies in women exposed to simvastatin or another
structurally related statin, 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.
Simvastatin was not teratogenic in rats or rabbits at
doses (25, 10 mg/kg/day, respectively) that resulted in 3 times the human
exposure based on mg/m² surface area. However, in studies with
another structurally-related statin, skeletal malformations were observed in
rats and mice.
Women of childbearing potential, who require treatment
with Simvastatin Oral Suspension for a lipid disorder, should be advised to use
effective contraception. For women trying to conceive, discontinuation of
Simvastatin Oral Suspension should be considered. If pregnancy occurs,
Simvastatin Oral Suspension should be immediately discontinued.
Nursing Mothers
It is not known whether simvastatin is excreted in human
milk. Because a small amount of another drug in this class is excreted in human
milk and because of the potential for serious adverse reactions in nursing
infants, women taking simvastatin should not nurse 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].
Pediatric Use
Safety and effectiveness of simvastatin in patients 10-17
years of age with heterozygous familial hypercholesterolemia have been
evaluated in a controlled clinical trial in adolescent boys and in girls who
were at least 1 year post-menarche. Patients treated with simvastatin had an
adverse reaction profile similar to that of patients treated with placebo. Doses
greater than 40 mg have not been studied in this population. In this limited
controlled study, there was no significant effect on growth or sexual
maturation in the adolescent boys or girls, or on menstrual cycle length in
girls. [See DOSAGE AND ADMINISTRATION, ADVERSE REACTIONS, Clinical
Studies] Adolescent females should be counseled on appropriate
contraceptive methods while on simvastatin therapy [see CONTRAINDICATIONS
and Use In Specific Populations]. Simvastatin has not been studied in
patients younger than 10 years of age, nor in premenarchal girls.
Geriatric Use
Of the 2,423 patients who received simvastatin in Phase
III clinical studies and the 10,269 patients in the Heart Protection Study who
received simvastatin, 363 (15%) and 5,366 (52%), respectively were ≥65
years old. In HPS, 615 (6%) were ≥75 years old. No overall differences in
safety or effectiveness were observed between these subjects and younger
subjects, and other reported clinical experience has not identified differences
in responses between the elderly and younger patients, but greater sensitivity
of some older individuals cannot be ruled out. Since advanced age ( ≥65
years) is a predisposing factor for myopathy, Simvastatin Oral Suspension
should be prescribed with caution in the elderly. [See CLINICAL PHARMACOLOGY]
A pharmacokinetic study with simvastatin showed the mean
plasma level of statin activity to be approximately 45% higher in elderly
patients between 70 to 78 years of age compared with patients between 18 to 30
years of age. In 4S, 1,021 (23%) of 4,444 patients were 65 or older.
Lipid-lowering efficacy was at least as great in elderly patients compared with
younger patients, and simvastatin significantly reduced total mortality and CHD
mortality in elderly patients with a history of CHD. In HPS, 52% of patients
were elderly (4,891 patients 65 to 69 years and 5,806 patients 70 years or
older). The relative risk reductions of CHD death, non-fatal MI, coronary and
non-coronary revascularization procedures, and stroke were similar in older and
younger patients [see Clinical Studies]. In HPS, among 32,145 patients
entering the active run-in period, there were 2 cases of
myopathy/rhabdomyolysis; these patients were aged 67 and 73. Of the 7 cases of
myopathy/rhabdomyolysis among 10,269 patients allocated to simvastatin, 4 were
aged 65 or more (at baseline), of whom one was over 75. There were no overall
differences in safety between older and younger patients in either 4S or HPS.
Because advanced age ( ≥65 years) is a predisposing
factor for myopathy, including rhabdomyolysis, Simvastatin Oral Suspension
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]
Renal Impairment
Caution should be exercised when Simvastatin Oral
Suspension is administered to patients with severe renal impairment. [See
DOSAGE AND ADMINISTRATION]
Hepatic Impairment
Simvastatin Oral Suspension is contraindicated in
patients with active liver disease which may include unexplained persistent
elevations in hepatic transaminase levels [see CONTRAINDICATIONS and WARNINGS
AND PRECAUTIONS].
REFERENCES
2 Manson, J.M., Freyssinges, C., Ducrocq, M.B.,
Stephenson, W.P., Postmarketing Surveillance of Lovastatin and Simvastatin
Exposure During Pregnancy, Reproductive Toxicology, 10(6): 439-446, 1996.