On the safety of reduced nicotinamide adenine dinucleotide (NADH)

The objective of the study was to determine both the toxicity of the stabilized orally absorbable form of nicotinamide adenine dinucleotide (NADH) (ENADA) and the maximum tolerated intravenous dose (MTD) of betaNADH (the reduced form of NADH) in beagle dogs. The administration of the stabilized orally absorbable form of NADH to beagle dogs at dose levels of 20, 100, and 150 mg/kg for 14 days elicited no signs of a toxicological effect. A transitory change in stool formation was observed with the intermediate and high dose in males. There were also apparent increases in adrenal, heart, kidney, liver, brain, and thyroid weights, particularly in males, but none of these changes were considered to be toxicologically significant. In addition, four dogs (two of each sex) received intravenous infusions of 100 mg NADH/kg/day for 4 days, followed by 200 mg NADH/kg/day for 3 days, followed by 500 mg NADH/kg/day for 4 days, and 1000 mg NADH/kg/day on the final day. At the end of the MTD phase, the control animals that had received saline solution in the MTD phase were used to evaluate the potential toxicity of the established MTD. These animals received 500 mg NADH/kg/day for 14 days (fixed dose phase). There were no deaths. At dose levels between 100 and 1000 mg/kg/day, effects on the cardiovascular system and also some evidence of an effect on the central nervous system and on the adrenals were observed. At doses of 500 mg/kg/day and above, food consumption and body weight were reduced. On the basis of the observed changes, the maximum intravenous dose of NADH tolerated by beagle dogs was considered to be 500 mg/kg/day. There were no gross histological findings indicative of toxicity in the organs of tissues examined. Based on these findings, the stabilized orally absorbable form of NADH (ENADA) can be regarded as safe.