['To determine if low-dose lovastatin in combination with niacin causes a greater percentage reduction in low-density lipoprotein (LDL) cholesterol than lovastatin alone, and to determine if the combination increases the risk of serious adverse effects. design. Prospective, randomized, open-label, clinical trial. setting. Family medicine clinic of a university-affiliated hospital. Patients. Patients with fasting LDL cholesterol concentrations of at least 150 mg/dl after 4 weeks of dietary stabilization and washout of any cholesterol-lowering drugs.', 'Twenty-eight patients received lovastatin 20 mg/day for 4 weeks after dietary stabilization and washout. If LDL cholesterol remained above 130 mg/dl (100 mg/dl in patients with coronary artery disease), they were randomized to receive either lovastatin 40 mg/day or a combination of lovastatin 20 mg/day and niacin 500 mg 3 times/day.', 'There was no difference in actual or percentage reductions of LDL cholesterol, total cholesterol, and triglycerides between the groups. A greater increase in high-density lipoprotein (HDL) cholesterol occurred with combination therapy (p = 0.024). There was no difference in liver function tests, glucose, or uric acid between the therapies. Based on drug-acquisition cost, combination therapy is approximately 40% less expensive than monotherapy.'] Is combination therapy with low-dose lovastatin and niacin as effective as higher-dose lovastatin?