Effect of Intravenous Vitamin C on Serum Level and Urinary Excretion of Methadone in Patients with Methadone Poisoning: A Randomized Single-Blind Clinical Trial

Methadone poisoning intentionally or accidentally leads to a high rate of treatment burden and cost and deaths. The evaluation of the factors affecting the severity of poisoning can reduce recovery time, costs, and potential risks.

This study aimed to investigate the effect of intravenous vitamin C (ascorbic acid) administration on serum level and urinary excretion of methadone.

In this single-blind study, 54 patients who were diagnosed with methadone poisoning were divided into three groups. The two intervention groups received different doses of vitamin C, including 12 and 24 g, and the control group received normal saline. The serummethadone level and urine pH weremeasured at the time of arrival and 24 hours after admission. The data were analyzed using repeated measure analysis of variance (ANOVA) in STATA version 12.

In this study, 18 patients were placed in each group. The three groups were not significantly different in basic variables, such as age, gender, and methadone dosage. Between and within-group comparison showed a significant decrease in the serum methadone levels over time after adjusting age, gender and methadone dosage (P < 0.05). Post-hoc analyses revealed a significant difference in methadone reduction between 12 g of vitamin C and control groups (P = 0.04), and there was no significant difference between the control and 24 g of vitamin C groups (P > 0.05). However, between and within-group comparisons showed no significant difference between the three groups in terms of urine pH (P > 0.05). In addition, interaction was observed between intervention and time on serum methadone levels (P < 0.001) and urine pH (P = 0.04) variables.

Consuming 12 g of vitamin C further reduced the serum methadone level in patients with methadone poisoning. There was no effect on methadone urinary excretion in patients.