Recommendations from others
Elevated hepatic enzymes <3 times the ULN may occur but usually resolve with continued therapy or reduced doses. Enzymes >3 times the ULN require discontinuation of therapy.8 The American Society of Health-System Pharmacists (ASHP) recommends screening at baseline, every 2 to 3 months for the first year and every 6 to 12 months there-after.8 The ASHP also recommends that patients be started on IR niacin products, with consideration of ER products only when IR products are not tolerated or alternative products are ineffective. ASHP makes no mention of LA/SR products in their recommendations.8 They recommend more frequent monitoring for high-risk patients—risks include doses >2 g/d for LA/SR and >3 g/d for IR; LA/SR formulations; switching between formulations; taking concomitant drugs that interact (ie, sulfonylureas); excessive alcohol use (undefined); and preexisting liver disease (based on a bivariate analysis of factors associated with increased risk of hepatic toxicity from a single retrospective cohort study)5 — and for patients who demonstrate signs/symptoms of toxicity (nausea, vomiting, malaise, loss of appetite, right upper quadrant pain, jaundice, and dark urine).8 The National Cholesterol Education Program Expert Panel update in 2004 recommended obtaining ALT/AST initially, 6 to 8 weeks after reaching a daily dose of 1500 mg, 6 to 8 weeks after reaching the maximum daily dose, then annually or more frequently if indicated.7
Clinical commentary
Risk of toxicity with long-acting niacin is significant enough to avoid use
Louis Sanner, MD
University of Wisconsin Medical School, Madison Family Practice Residency
Our clinical experience is that once our patients are on stable doses of most medicines and have had a series of normal lab tests, we are unlikely to find toxicities from continued routine testing. That appears to be the case with niacin and liver toxicity, but long-term data are lacking for asymptomatic late reactions to usual niacin doses. The risk of toxicity with “long-acting” forms of niacin is significant enough that I see no reason to use them at all. If one wants to save money, use IR niacin. If cost is not an issue or regular niacin is not tolerated, I use the ER Niaspan. Both of these forms have very low rates of liver toxicity.