There are not many differences between simvastatin and pravastatin as they both belong to the same class of cholesterol-lowering drug and act by the same mechanism of action. Their pharmacokinetics, potential for interactions with other medicines and normal dosage, however, differ slightly. Both drugs are usually available by prescription only and may be available as different trade names in different countries, according to manufacturer.
Both simvastatin and pravastatin are HMG CoA reductase inhibitors, commonly referred to as statins. By inhibiting HMG CoA reductase, an enzyme involved in the synthesis of cholesterol in the body, cholesterol levels are lowered. High cholesterol levels, or hypercholesterolemia, a very common problem worldwide, can cause blocking of the blood vessels and increase the risk of serious conditions such as stroke, heart attack and kidney disease. While lifestyle changes may first be recommended, such as a change in diet and exercise, medication is often required to lower cholesterol levels.
Cholesterol is synthesized in the body mainly at night, so it is recommended that statins with a short half-life such as these, be taken at night to ensure maximal effect. The half-life of a drug refers to how long it remains at a certain level in the body, so the shorter the half-life, the shorter the time of action. In most cases, statins are taken as a once daily dose.
Simvastatin and pravastatin also differ in the strength which is usually used. Simvastatin is usually given at a dose of 10mg at night initially and may be increased slowly, usually at four-weekly intervals, up to a maximum of 80mg daily, depending on tolerance and response. Pravastatin is also usually started at 10mg daily and worked up, similarly at four week intervals, but to a maximum of 40mg.
As with any medication, both drugs may interact with other medications, including homeopathic, over-the-counter and complementary medicines. These should be discussed with the prescribing doctor before initiating treatment with either drug. Pravastatin tends to be slightly less susceptible to interactions due to the fact that it is not metabolized by the cytochrome P450 system, a system which can often cause interactions due to inhibition or induction of the system by other medications.
Adverse reactions may occur with both drugs, and are generally dose-related for both. Some side effects that have been reported include gastrointestinal side effects, muscle effects and liver toxicity. The prescribing doctor will monitor patients on statins closely for any signs of serious adverse effects and, should any be experienced, the patient should contact their doctor immediately.