Simvastatin is an antihyperlipidemic medication that contains active ingredient called simvastatin. It belongs to a family of drugs called statins or HMG CoA reductase inhibitors. This drug has been studied in many large outcome trials and it has demonstrated many beneficial effects in terms of reducing the risk of heart attack and other complications of the circulatory system. It works by lowering LDL cholesterol up to 47% when used at maximum daily dose (80 mg). It also demonstrated mild increase in levels of HDL cholesterol and mild decrease in levels of Apo lipoprotein B and triglycerides.
Studies have shown that this drug is actually a chemical derivative of lovastatin (a drug that is also used to lower cholesterol) but is two times more potent than lovastatin.
When administered at a dose of 40 mg once a day, this drug is efficient in the treatment of heterozygous familial hypercholesterolemia because it lowers the level of LDL cholesterol up to 45%.
If applied regularly, simvastatin can reduce mortality by 30% in high-risk patients.
precaution
clinical studies have shown that the most common side effect is a headache which is usually mild and last only a few days. Other commonly reported adverse effect of simvastatin include
1-diarrhe
2- Constipation
3- Flatulence and dyspepsia
4- Stomach ache
The only serious side effect that has been reported in less than 0.01% of patients is rhabdomyoelisis- muscle breakdown and subsequent acute renal failure. Which can be endanger the patient’s life.
It is essential that you see your doctor at the first sign of rhabdomyoelisis (muscle cramp, muscle pain, muscle inflammation of unknown cause) . it is recommended to regularly control the level of myoglobin in the blood during the first 3 month of therapy.
Simvastastatin can cause mild to moderate liver damage, which is manifested by a transient increase of the enzyme called aspartate aminotransferase and alanine aminotransferase sever liver damage in patient who are treated whit this drug have also been reported in a very small number of patient . if you notice sign of liver damage such as jaundice pain in the upper right abdomen or severe nausea .you must see your doctor immediately. Taking of larger doses as well as the concomitant use whit other antihyperlipidemic agents increase the risk of rhabdomyolisis and liver injury. Generally this drug has an excellent safety profile which is why UK regulatory authorities approved this drug for purchase without a prescription but only for a dose of 10 mg
Pregnancy and breastfeeding
AU TGA classifies simvastatin in group D because it may cause malformations or irreversible damage to the fetus and it must not be used during pregnancy
Cholesterol is important for proper prenatal fetal development and is involved in forming of many tissue in the baby which is why its consumption during pregnancy is not recommended. It should not be used during breastfeeding because it can effect the metabolism of fat in infants. How to use
How to use
The dose is in the range of 10 - 80 mg once a day depending on the level of LDL cholesterol in the blood.
You should always use the minimum effective dose (lowest dose which reduces cholesterol levels to normal levels) because taking higher doses increase the risk of myopathy and hepatotoxicity. A dose of 80 mg should be used only in patients having a very high risk of a heart attack or stroke.
It is best to take tablet at bedtime, because studies have shown that the efficacy of simvastatin is higher at night.
You should not drink grapefruit juice while on treatment with this drug, because grapefruit contains substances that inhibit the CYP3A4 enzyme responsible for the metabolism of simvastatin for this reason, the concomitant use with grapefruit juice significantly increases the concentration of simvastatin in the blood and consequently increases the risk of side effects.
INTERACTION

Simvastatin should not be taken simultaneously with the following medicines:
•Cyclosporine (a drug used to prevent rejection of transplanted organs)
•Calcium antagonists that exhibit an effects in the heart, such as:
•Verapamil
•Diltiazem
•Nefazodone (an antidepressant). This drug is no longer approved for use in most countries because of its hepatotoxic effects. Co-administration with simvastatin increases the risk of severe liver damage.
Antibiotics such as:
Teltiromycin,erythromycin,claritromycin
These drugs are (as grapefruit juice) inhibitors of CYP3
antifungal medications(itraconazol, fluconazole, and ketoconazole)
Anti-arrhythmics (e.g. amiodaron)
Boceprevir-a drug used to treat hepatic c
Medicine to treat AIDS such as indinavir, atazanavir, cobicistat,ritonavir,,fosamprenavir, saquinavir and others
Danazol
•Gemfibrozil, clofibrate and fenofibrate –drug used for triglycerides in the blood
•Niacin
•Colchicine

Side effect
Simvastatin can cause the following side effect:
Tingling, headache, gastrointestinal, adverse event (bloating, constipation, diarrhea, nausa, vomiting, abdominal pain, and dyspepsia)
Weakness or numbness in hand and feet. Itching, alopecia, muscle cramp, inflammation of muscle, muscle weakness, rhambdomyolisis, inflammation of blood vessel, photosensivity, hepatotoxicity
If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.