What are the Simvastatin side effects?

Simvastatin is a drug used for lowering the level of lipids especially cholesterol in the blood. In other words it is a lipid lowering or hypolipidemic drug. It is classified in group of lipid lowering agents named as Statins or HMG-CoA reductase inhibitors. Other drugs included in this group are Atorvastatin, Rosuvastatin, Fluvastatin, Lovastatin, Pravastatin and Pitavastatin.

Simvastatin is marketed all over the world with different brand names like Zocor, Lipex or Simva etc. Simvastatin was first produced from a fungus named as Aspergillus terreus.

Cholesterol is naturally synthesized in our body by complex pathways. In this pathway one of the steps is conversion of HMG-CoA to mevalonate in the presence of HMG-CoA reductase. Mevalonate is further converted to cholesterol. It is the point where Simvastatin inhibits the conversion of HMG-CoA to mevalonate by suppressing the enzyme HMG-CoA reductase in the liver. Moreover, it also increases the uptake of Low density lipoprotein (LDL or bad cholesterol) by the liver. Thus bad cholesterol is driven away from the circulation to the liver where it is broken down.

Additional effects of Simvastatin are:

  • Improved function of endothelium
  • Modulation of inflammatory processes and responses
  • Stability of atherosclerotic plaques
  • Prevention of formation of thrombus


What is Simvastatin used for?

In order to manage increased blood cholesterol levels, physicians always advise the patient to modify their lifestyle that includes diet restriction, weight reduction and adequate physical activity. If all these measures fail, then the role of lipid lowering agents comes and Simvastatin is prescribed to lower the cholesterol level in the blood.

The common uses of Simvastatin are:

  • Primary prevention – numerous studies have shown that Simvastatin plays a vital role in lowering of cholesterol levels in the blood. High cholesterol level in the blood predisposes to atherosclerosis which may lead to cardiovascular or neurovascular diseases. So, by decreasing cholesterol level in the blood, Simvastatin prevents the incidence of untoward cardiovascular or neurovascular diseases
  • Secondary prevention – Simvastatin has a well documented role in the keeping the cholesterol level in range in the patients already suffering from cardiovascular disease. Its use has decreased the incidence of myocardial infarctions in the individuals having previous episode of ischemic heart disease

Common side effects of Simvastatin

The common side effects of Simvastatin are:

  • Heptatic or liver damage – Simvastatin is known to cause liver damage if used chronically. Although the damage caused by this drug is not much severe, however, it deranges the liver function tests. Liver function tests settle to the normal limits after stopping the drug
  • Rhabdomyolysis (Skeletal muscle breakdown) – It is a potentially serious side effect of Simvastatin. Long term use causes muscle inflammation and myoglobin is released. Initially myoglobinuria occurs that may eventually lead to renal failure. Although it may even lead to death, however, it is very rare.
  • Muscle cramps or myalgias – few patients on this drug have reported occasional aches and pains in skeletal muscles.
  • Neuropsychiatric disorders – the most common is the memory impairment. Patients complain of forgetfulness andremain confused. This side effect also diminishes within two weeks after discontinuing the drug. Few studies show that Simvastatin use may damage the peripheral nerves and cause polyneuropathy.
  • Diabetes – Simvastatin use may predispose an individual to diabetes as it increases the fasting sugar level in the blood. Moreover, it increases the level of glycosylated hemoglobin (HbA1C) in the blood.
  • Simvastatin use may increase the risk of developing cancer in the patients.
  • Allergic reactions – although serious allergic reactions are rare with the use of Simvastatin, however, few cases of rash or difficulty breathing or swallowing are observed with this drug.
  • Joint pains
  • Pancreatitis – simvastatin may damage pancreatic cells
  • Hematologic disturbances – it may be due to hypersensitivity reactions. Common problems associated with Simvastatin use are hemolytic anemia, thrombocytopenia, leucopenia and leukemia.
  • Simvastatin intereferes with the metabolism of estrogen in the liver, which is required for normal sleep. So, Simvastatin is believed to cause insomnia.

Other general side effects associated with Simvastatin use are:

  • Nausea
  • Vomitting
  • Abdominal cramps and pains
  • Diarrhea

Simvastatin side effects on children

Simvastatin is not advised for the children less than ten years of age. Common side effects of Simvastatin on children are nausea, abdominal cramps and headache. Children or adolescents may have other side effects of the drug but are rare in this age group.

Simvastatin side effects on men

In addition to common side effects of Simvastatin, men can specifically have decreased libido, impotence and enlargement of breasts. Moreover, it may cause testicular pain.

Simvastatin side effects on women

Simvastatin increases the risk of Type II Diabetes Mellitus especially in postmenopausal women. Moreover, alopecia and decrease sexual arousal are a few common side effects of Simvastatin in women.

Simvastatin side effects on pregnant women

Cholesterol is required for the normal development of fetus. Simvastatin reduces the cholesterol level and blood and may hinder the normal development process of the fetus. So, it must be avoided in the women who are pregnant or planning to conceive. However, Simvastatin can be taken safely by the women of child bearing age not planning to conceive. Moreover, Simvastatin is not recommended for the breastfeeding mothers due to the side effects.

Simvastatin side effects on elderly

Muscle damage and breakdown can be disastrous in the elderly in whom the muscle mass and strength is already on the lower side. If Simvastatin use further decreases the muscle mass, it can be debilitating in them.

In 2002, American Heart Association carried out a study on Simvastatin and revealed that following factors increases the risk muscular breakdown:

  • Old age (> 80 years)
  • Women > men
  • Concomitant use of other drugs

Loss of cognition is another side effect that occurs more commonly in the elderly as compared to the normal population.

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