Does N-Acetyl Cysteine Have a Dose-Dependent Effect on Plasma Homocysteine Concentration in Patients Undergoing Hemodialysis?

High homocysteine (Hcy) levels in hemodialyzed patients are associated with coronary disease. On the other hand, different effects were reported for impact of N-Acetyl Cysteine (NAC) on plasma Hcy levels in patients undergoing hemodialysis. The current study was conducted to evaluate the effect of oral NAC on plasma Hcy values in hemodialysis patients, comparing to placebo.
This double blind randomized clinical trial study was done on 99 ESRD subjects undergoing hemodialysis with hyperhomocysteinemia at three dialysis centers in 2008. The effect of one month consumption of 3 different doses of oral NAC (600, 1200 and 1800 mg daily) were assessed on plasma Hcy concentration. Each group was randomly divided into two sub-groups of drug (n=15, 19 and 14, respectively) and placebo (n=18, 19 and 14, respectively).
There were significant differences between groups 2 (1200 mg daily) and 3 (1800 mg daily) of NAC within the study (P=0.000 and 0.004, respectively). Furthermore, there was a relation between the rate of reducing plasma Hcy concentrations and the higher doses of NAC (P=0.000), it means that the effect of drug was dose-dependent. On the other hand, highest dose of drug (1800 mg per day) caused GI disterbance in 5 patients without further effect than 1200 mg daily dose of NAC (P=0.6).
The current study showed that oral NAC in dialysis patients for normalization of the plasma Hcy level has been successful and appeared to be dose-dependent.