Inclusion Criteria:

• HIV-infected.
• Stable antiretroviral therapy for 3 months to 1 month prior to study entry and planning to stay on current therapy. No changes in antiretroviral therapy will be allowed in the 1-month period prior to study entry.
• Fasting non-HDL-C >= 180 mg/dl and serum triglycerides > 200 mg/dl within 30 days of study entry.
• Willing to stay on the Lipid-Lowering Diet and Activity Guide for the length of the study.
• Women of reproductive potential must have a negative serum or urine pregnancy test performed within 14 days prior to study entry.
• Agrees to use acceptable methods of contraception while receiving protocol-specified medication and for 4 weeks after stopping the medication. Patients who are not of reproductive potential are eligible without requiring the use of contraception.
• Men who have been on stable testosterone replacement for at least 3 months prior to entry and plan to continue a stable dose during the study may enroll.
• Hormone replacement therapy for postmenopausal women and for transgendered patients will be allowed, but not required. Oral contraceptive therapy will be allowed. Patients must be on stable hormone replacement therapy for at least 30 days prior to study entry and plan to continue a stable dose during the study.

Exclusion Criteria:

• LDL-C >= 200 mg/dl or non-HDL-C > 250 mg/dl (if the LDL-C cannot be calculated because the triglycerides are > 400 mg/dl).
• Coronary heart disease (CHD) or CHD risk equivalent, including but not limited to peripheral vascular disease, cerebrovascular disease, or abdominal aortic aneurysm.
• Congestive heart failure.
• Uncontrolled hypertension within 30 days of study entry, from an average of 2 or more readings on 2 or more occasions.
• Acute arthritic gout symptoms within 60 days of study entry.
• Active peptic ulcer disease.
• Diabetes mellitus that requires pharmacological or dietary control.
• Untreated hypothyroidism. Patients with treated hypothyroidism are allowed.
• Levothyroxine and liothyronine for uses other than for hypothyroidism.
• Active or symptomatic gallbladder disease within 1 year of study entry. Patients with asymptomatic gallstones are allowed. Patients with a history of a cholecystectomy will be allowed provided that the procedure was done at least 3 months before study entry.
• Active cancer within the last 5 years or a new diagnosis of cancer within the last 5 years. Skin cancers, including Kaposi's sarcoma, not requiring systemic treatment are allowed.
• Pregnancy or breast-feeding.
• Any prescription lipid-lowering agent within 30 days of study entry.
• Niacin or niacin-containing products that contain > 100 mg daily within 30 days prior to study entry.
• Systemic cancer chemotherapy or immunomodulators within 60 days of study entry.
• Investigational antiretroviral drugs in AACTG studies and expanded access trials will be allowed. Other investigational therapies that are not FDA-approved will not be allowed within 30 days of study entry unless permission is granted by study chairs.
• Systemic glucocorticoids above replacement levels within 60 days of entry.
• Certain antidiabetic medications.
• Allergy/sensitivity to the study drug or its formulations.
• Allergy, sensitivity, or severe intolerance to all of the following 3 medications: aspirin, ibuprofen, and naproxen.
• Active drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements.
• Decreased mental capacity that, in the opinion of the site investigator, would interfere with adherence to study requirements.
• Active AIDS-defining opportunistic infection (OI) within 30 days prior to entry. Patients who have no evidence of active disease and are receiving maintenance therapy for AIDS-related OIs will be eligible.
• Acute illness within 30 days prior to entry that, in the opinion of the site investigator, would interfere with participation in the study.