Part A: This study will determine that MK0524 is well tolerated and does not effect lipids and blood glucose when given alone.

Part B: Determine dose ranges for MK0524 and MK0524 plus Niaspan(R) on the effects of lipids and blood glucose.

Inclusion Criteria:

• Men and women, 18 to 70 years of age for whom treatment with Niacin would be appropriate but who are not taking > 50mg at screening
• Must be willing to complete electronic diary

Exclusion Criteria:

• Subject is having menopausal hot flashes and/or receiving hormone replacement therapy (HRT)
• You have a history of cancer, gout, peptic ulcers, diabetes, liver, heart disease or high blood pressure or you are HIV positive
• You consume more than 14 alcoholic drinks per week or more than 2 drinks per day