Background. Substitution treatment of drug addicts with methadone has been used in many countries for more than 35 years. In our country it was started in 1997. The objective was above all to evaluate the nutritional status and some biochemical parameters before and after 18 months of methadone substitution. Methods and Results. A total of 14 patients were examined (9 men, 5 women), mean age 35 years, range 26 - 44 years, highly dependent on opiates: heroin, codeine and its derivatives). The examination was made before onset of treatment and after 18 months of treatment. The subjective feeling of all patients improved, they felt more active and efficient. The Kehlet score declined from 5.8 ± 1.9 to 3.8 ± 1.5. The body weight increased from 69.3 ± 14.8 to 78.6 ± 19.7 kg. BMI from 22.8 ± 3.2 to 25.5 ± 5.0 (kg/m 2 ), the skinfold above the triceps muscle from 11.9 to 16.6 mm, prealbumin from 0.17 ± 0.05 to 0.22 ± 0.66 g/l). The handgrip strength did not increase, no significant changes were recorded in albumin and transferrin levels. The raised serum aminotransferase levels did not change (due to chronic hepatitis). Conclusions. Substitution treatment of drug addicts with methadone leads not only to improvement of the subjective state but also to objective signs of a better nutritional status.

        Key words: toxicomania, substitution treatment, methadone, nutrition, laboratory paramet ers of the nutritional status.