Lipid and transaminase concentrations after formulary conversion of Niaspan to Slo-Niacin

Lipid and transaminase levels after conversion from immediate-release niacin to extended-release niacin were evaluated.

All patients who had their medications converted from Niaspan to Slo-Niacin between March 2008 and January 2009 were considered for evaluation. Subjects who took =2000 mg of Niaspan were automatically converted to Slo-Niacin in a 1:1 dosing ratio conversion. Mean aspartate transaminase (AST) and alanine transaminase (ALT) levels and lipid values (low-density-lipoprotein [LDL] cholesterol, high-density-lipoprotein [HDL] cholesterol, and triglyceride levels) during Niaspan therapy were compared with the means of these values obtained after at least 90 days of Slo-Niacin therapy. Data were analyzed using the Wilcoxon rank-order test and frequency distributions.

Of the 1172 patients who were identified as having had their Niaspan switched to Slo-Niacin after formulary conversion, 142 met the inclusion criteria for this study. The majority of the patients had a decrease or no change in AST (72.5%) and ALT (69%) levels after at least 90 days of Slo-Niacin therapy. None of the patients had transaminase levels greater than three times the upper limit of normal during Slo-Niacin therapy. Differences in AST, ALT, triglyceride, and LDL cholesterol levels were not statistically significant between Niaspan and Slo-Niacin. On the other hand, patients' mean HDL cholesterol level was significantly greater with Slo-Niacin therapy than with Niaspan (42 mg/dL versus 40 mg/dL, respectively; p < 0.05).

Formulary conversion from Niaspan to Slo-Niacin resulted in a small but significant increase in HDL cholesterol concentration and no significant change in ALT or AST level.