THE EFFECT OF NICOTINIC-ACID AND ACIPIMOX ON LIPOPROTEIN(A) CONCENTRATION AND TURNOVER

This study examines the effect of nicotinic acid (1 g t.d.s.) on serum Lp(a) concentration in a group of patients with type II hyperlipidaem ia selected on the basis of a plasma Lp(a) concentration greater than 30 mg/dl. Reductions in total cholesterol, triglyceride, LDL-cholester ol and Lp(a) were 16.3%, 25.5%, 23.7% and 36.4%, respectively, with an increase in HDL cholesterol of 37.3%. The reduction in Lp(a) concentr ation did not correlate with any other lipoprotein changes. In order t o establish the mechanism of the fall in Lp(a) concentration, in vivo turnover of autologous Lp(a) was studied in three subjects before and whilst taking nicotinic acid. The fractional catabolic rate in Lp(a) w as unaltered in the subjects on therapy, indicating that nicotinic aci d did not increase catabolism of Lp(a) but decreased the synthetic rat e. Since nicotinic acid was poorly tolerated we examined the effect of acipimox, an analogue of nicotinic acid on lipoproteins using a place bo controlled double-blind crossover design in a group of hyperlipidae mic patients again selected with plasma Lp(a) concentration greater th an 30 mg/dl. Acipimox was better tolerated than nicotinic acid but the percentage changes in lipoprotein concentrations were smaller.