INTRODUCTION:
Cholesterol is a lipid that is carried through the bloodstream. Although cholesterol is necessary for cell function and hormones, elevated levels may accumulate in the blood. High cholesterol levels (hypercholesterolemia) places unnecessary stress on the vascular system, increasing the risk of hardening and narrowing of the arteries (atherosclerosis), cardiovascular disease, heart attack, and strokes.

Cholesterol levels may be lowered by lifestyle changes, including diet regulation and increased exercise. In some cases, cholesterol-lowering medications is used. The most popular and effective medications are the statins, HMG-CoA reductase inhibitors. They reduce the amount of cholesterol and certain fatty substances in the blood by inhibiting the enzyme required by the body to produce cholesterol. Two of these statins include pravastatin (Pravachol) and simvastatin (Zocor).

Many drug interactions are a result of inhibition or induction of enzyme CYP3A4 from the liver cytochrome P450 (CYP450). Components of grapefruit juice are metabolized by the same enzyme and acts as a competitive inhibitor. The inhibition of CYP3A4 results in dangerous levels of medication accumulating in the blood. Adverse effects including muscle pain, fatigue, fever, and on rare occasions, kidney failure and death may occur.

Itraconazole is a drug used for the treatment of fungal infections. However, it is a known inhibitor of CYP3A4 and may cause negative side effects if used concomitant with cholesterol-lowering drugs. Other cholesterol lower drugs such as fenofibrate and niacin, if used in conjunction with HMG-CoA reductase inhibitors, may cause potentially hazardous drug interactions.