A Study to Evaluate Efficacy and Safety of Extended-Release Niacin + Laropiprant + Simvastatin in Participants With Primary Hypercholesterolemia or Mixed Dyslipidemia (MK-0524B-118)

Inclusion criteria * Participant has a history of primary hypercholesterolemia or mixed dyslipidemia and meets LDL-C and triglyceride criteria. * Visit 2: * Participant is high risk coronary heart disease (CHD) or CHD risk-equivalent. Exclusion Criteria * Participant is pregnant or breast-feeding, or expecting to conceive during the study. * Participant has a history of malignancy. * Participant consumes more than 3 alcoholic drinks per day (14 per week). * Participant is high risk CHD patient on statin therapy or any patient on statin therapy equivalent to 80 mg simvastatin. * Participant with Type 1 or Type 2 diabetes mellitus that is poorly controlled, or on statin therapy. * Participant currently engages in vigorous exercise or is on an aggressive diet regimen. * Participant uncontrolled endocrine or metabolic disease, uncontrolled gout, kidney or hepatic disease, heart failure, recent peptic ulcer disease, hypersensitivity or allergic reaction to niacin or simvastatin, recent heart attack, stroke or heart surgery. * Participant is human immunodeficiency virus (HIV) positive. * Participant has taken niacin \>50 mg/day, bile-acid sequestrants, hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase inhibitors, ezetimibe, Cholestin™ \[red yeast rice\] and other red yeast products within 6 weeks, or fibrates within 8 weeks of randomization visit (Visit 3). * Note: Fish oils, phytosterol margarines and other non-prescribed therapies are allowed provided participant has be…