Multicenter trial of L-carnitine in maintenance hemodialysis patients. II. Clinical and biochemical effects

Abstract

Since carnitine deficiency has been reported in some patients undergoing maintenance hemodialysis, we studied the effects of intravenous infusion of L-carnitine or placebo at the end of each dialysis treatment. The trial, which lasted seven months (one month baseline, 6 months treatment) was multicenter, double blind, placebo controlled, and randomized. Eighty-two long-term hemodialysis patients, who were given either carnitine (N = 38) or placebo (N = 44), completed this study. In each group, clinical and biochemical parameters during treatment were compared with baseline values. Intra-dialytic hypotension and muscle cramps were reduced only in the carnitine treated group, while improvement in post-dialysis asthenia was noticed in both carnitine and placebo groups. Maximal oxygen consumption, measured during a progressive work exercise test, improved significantly in the carnitine group (111 ± 50 ml/min, P < 0.03) and was unchanged in the placebo group. L-carnitine treatment was associated with a significant drop in pre-dialysis concentrations of serum urea nitrogen, creatinine and phosphorus (x̄ ± SEM, 101 ± 4.5 to 84 ± 3.9, 16.7 ± 0.67 to 14.7 ± 0.64, and 6.4 ± 0.3 to 5.5 ± 0.4 mg/dl, respectively, P < 0.004). No significant changes in any of these variables were noticed in the placebo group. Mid-arm circumference and triceps skinfold thickness were measured in 11 carnitine and 13 placebo treated patients. Calculated mid-arm muscle area increased in the carnitine patients (41.37 ± 2.68 to 45.6 ± 2.82 cm2, P = 0.05) and remained unchanged in the placebo patients. Assessment of global clinical status at the end of the study, prior to breaking the study drug administration code, revealed that 19 patients from the carnitine treated group (50%) and 8 from the placebo group (18%) had showed significant improvement (P < 0.005). Thus, intravenous L-carnitine in hemodialysis patients appears to be associated with a decrease in dialytic symptoms, an improvement in exercise capacity, sense of well being and certain serum chemistries, and possibly an increase in muscle mass.