To the Editor.
—The article by Dr McKenney and colleagues1 and the editorial comments of Dr Lasagna2 are important and useful, but do not support the authors' conclusion that SR formulations of nicotinic acid are more toxic than IR preparations. Clinical evaluation of relative toxicity requires a comparison of toxic manifestations at therapeutically equieffective doses rather than equal doses in milligrams. The data indicate that the hypocholesterolemic potency of the SR preparation is at least twice that of the IR formulation. Thus, the side effects of SR in doses of 1000 to 1500 mg daily should be compared with that of 2000 to 3000 mg of IR. The protocol called for sequential dose increases of both formulations regardless of cholesterol response. The clinical tolerance of SR is remarkably better. The liver function data should be compared at equieffective doses. Such analysis would probably show no significant toxicologic difference
Weiner M. Safety and Side Effects of Sustained-Release Niacin. JAMA. 1994;272(7):514. doi:10.1001/jama.1994.03520070031017