Drug Name
Generic Name : simvastatin
Brand Name: Apo-Simvastatin (CAN), Gen-Simvastatin (CAN), CO Simvastatin (CAN), Novo-Simvastatin (CAN), ratio-Simvastatin (CAN), Zocor
Classification: Antihyperlipidemic, HMG-CoA reductase inhibitor
Pregnancy Category X
Dosage & Route
Available forms : Tablets—5, 10, 20, 40, 80 mg
ADULTS
Initially, 20 mg PO; up to 80 mg PO daily in the evening. Usual range, 5–80 mg/day. Maximum dose, 80 mg/day. Adjust at 4-wk intervals.
- Familial hypercholesterolemia: 40 mg/day PO in the evening, or 80 mg/day divided into doses of 20 mg, 20 mg, and 40 mg in the evening.
- Combination therapy: Do not combine with other statins; if used with fibrates or niacin, do not exceed 10 mg/day; regular dose if combined with bile acid sequestrants. Combined with cyclosporine, start with 5 mg/day; do not exceed 20 mg/day. Combination with amiodarone or verapamil, dose should not exceed 10 mg/day.
PEDIATRIC PATIENTS (10–17 YR)
- 10 mg/day PO in the evening. Range, 10–40 mg/day based on response.
GERIATRIC PATIENTS AND PATIENTS WITH RENAL IMPAIRMENT
- Starting dose, 5 mg/day PO; increase dose slowly, monitoring response.
Therapeutic actions
- Simvastatin is a prodrug metabolised in the liver to form the active β-hydroxyacid derivative. This inhibits the conversion of HMG-CoA to mevalonic acid by blocking HMG-CoA reductase, an early and rate-limiting step in cholesterol biosynthesis. It reduces total cholesterol, LDL-cholesterol and triglycerides and increases HDL-cholesterol levels.
Indications
- Adjunct to diet in the treatment of elevated total cholestrol and LDL cholesterol with primary hypercholesterolemia (types IIa and IIb) in those unresponsive to dietary restriction of saturated fat and cholesterol and other nonpharmacologic measures
- To reduce the risk of coronary disease, mortality, and CV events, including CVA, TIA, MI and reduction in need for bypass surgery and angioplasty in patients with coronary heart disease and hypercholesterolemia
- Treatment of patients with isolated hypertriglyceridemia
- Treatment of type III hyperlipoproteinemia
- Treatment of adolescents 10–17 yr with heterozygous familial hypercholesterolemia
Adverse effects
- Headache, nausea, flatulence, heartburn, abdominal pain, diarrhea/constipation, dysgeusia; myopathy features like myalgia and muscle weakness; serum transaminases and CPK elevations; hypersensitivity; lens opacities; blurring of vision; dizziness; sexual dysfunction; insomnia; depression and upper respiratory symptoms.
- Potentially Fatal: Severe rhabdomyolysis with acute renal failure.
Contraindications
- Acute liver disease or unexplained persistent elevations of serum transaminases. Pregnancy, lactation. Porphyria.
Nursing considerations
Assessment
- History: Allergy to simvastatin, fungal byproducts; impaired hepatic function; pregnancy; lactation
- Physical: Orientation, affect; liver evaluation, abdominal examination; lipid studies, LFTs
Interventions
- Ensure that patient has tried a cholesterol-lowering diet regimen for 3–6 mo before beginning therapy.
- Give in the evening; highest rates of cholesterol synthesis are between midnight and 5 AM.
- Advise patient that this drug cannot be taken during pregnancy; advise patient to use barrier contraceptives.
- Arrange for regular follow-up during long-term therapy. Consider reducing dose if cholesterol falls below target.
Teaching points
- Take drug in the evening. Do not drink grapefruit juice while using this drug.
- Have periodic blood tests.
- This drug cannot be taken during pregnancy; using barrier contraceptives is recommended.
- You may experience these side effects: Nausea (eat frequent small meals); headache, muscle and joint aches and pains (may lessen); sensitivity to light (use a suncreen and wear protective clothing).
- Report severe GI upset, changes in vision, unusual bleeding or bruising, dark urine or light-colored stools, fever, muscle pain, or soreness.