What is this medication?
A cholesterol-lowering medication, synthetically derived from a fungus (Aspergillus terreus)
Statins (HMG-CoA inhibitor)
Mechanism of action:
HMG-CoA reductase inhibitors (statins), Simvastatin is metabolized by the cytochrome P450 isoform 3A4.
5, 10, 20, 40, 80 mg (in the evening)
Pediatric dosing and indication
<10 years old: Safety and efficacy not established
Indicated in adolescents 10-17 years old
Initial: 10 mg PO every evening; not to exceed 40 mg/day
Could it be cut in half?
Hepatic (liver) dosing: Hold if any active liver disease
Renal dosing: Severe kidney function impairment (CrCl <30 mL/min): 5 mg qday initially
Statins are a class of prescription drugs used together with diet and exercise to reduce blood levels of low-density lipoprotein (LDL) cholesterol.
Simvastatin and the FDA
- HIV Protease inhibitors (e.g. ritonavir, indinavir) and statins taken together may raise the blood levels of statins and increase the risk for muscle injury (myopathy).
- On 3/19/2010 the U.S. Food and Drug Administration (FDA) informed the public about an increased risk of muscle injury in patients taking the highest approved dose of the cholesterol-lowering medication, simvastatin 80 mg, compared to patients taking lower doses of simvastatin.
- The revised label states that patients of Chinese descent shouldn’t receive simvastatin 80 mg with cholesterol-modifying doses of niacin-containing products.
- Many studies have shown an improvement in cholesterol levels (35 to 45%) and survival (30%) in coronary heart disease patients. (1)
- The medication can be taken with or without food
- Because simvastatin (ZOCOR) doesn’t undergo significant renal excretion, modification of dosage shouldn’t be necessary for patients with mild to moderate renal impairment.
- Reports of increased blood sugar and glycosylated hemoglobin (HbA1c) levels have been added to the statin labels.
- There are also post-marketing reports of memory loss, forgetfulness, amnesia, confusion, and memory impairment.
- This medication is required to be taken in the evening for an optimal result.
Simvastatin and grapefruit
- Drinking large quantities (more than 1 quart [1 liter] a day) of grapefruit juice while taking simvastatin could result in increased rate of adverse effects.
Simvastatin side effects:
Most common side effects of this med are:
- Muscle pain (or myalgias)
Rare but serious side effects are:
- Liver failure
- Kidney failure from muscle breakdown (or rhabdomyolysis)
Warning and precautions
Do not use simvastatin with these medications
- HIV protease inhibitors
Don’t use more than 10mg of simvastatin with these medications:
Don’t use more than 20mg of simvastatin with these medications
Don’t use more than 40mg of simvastatin with this medication
That’s not all
Women who are pregnant or breastfeeding should not use simvastatin.
Simvastatin was approved for use in 1991. It belongs to a group of cholesterol-lowering medications and it’s synthetically derived from a fungus (Aspergillus terreus).
This statin is one of the most potent statins that are now available in a generic version.
Simvastatin has a much broader range of interactions with other medications compared to newer statins such as atorvastatin and rosuvastatin.
The FDA warnings regarding usage of a higher dosage of simvastatin 80 mg and limitations of using this medication with drugs such as calcium channel blockers (for example amlodipine) have been reducing the prescribing of this medication in clinical practice.
There are also other concerns regarding an increasing rate of high glucose levels, which is class-specific (statins) and not only related to simvastatin.
This medication is still a good choice in younger patients needing treatment with this class of drugs and in patients who are not taking any other drugs I’ve listed previously.
This Medication Guide summarizes the most important information (based on the author’s personal opinion) about the above medication and is not a complete medication guide. If you would like more information, talk to your doctor and your pharmacist. The ultimate judgment regarding your care must be made by you and your physician together, in light of circumstances specific to you as a patient.