ANKK1 and DRD2 pharmacogenetics of disulfiram treatment for cocaine abuse.

OBJECTIVE: Disulfiram is a potential cocaine addiction pharmacotherapy. Since dopamine deficiency has been found with cocaine addiction, our objective was to examine whether functional variants in the ankyrin repeat and kinase domain-containing 1 (ANKK1) and/or the dopamine receptor D2 (DRD2) genes interact with response to treatment with disulfiram. MATERIALS AND METHODS: Cocaine and opioid codependent (DSM-IV) patients were stabilized on methadone and subsequently randomized into treatment groups - disulfiram (250 mg/day, N=31) or placebo (N=37). They were genotyped for ANKK1 (rs1800497) and DRD2 (rs2283265) polymorphisms, and the data were evaluated for an association between a cocaine-free state, as assessed by cocaine-free urine samples, and disulfiram treatment. Data were analyzed using repeated measures analysis of variance corrected for population structure. RESULTS: Patients with CT or TT ANKK1 genotypes dropped from 80 to 52% cocaine-positive urines on disulfiram (N=13; P≤0.0001), whereas those on placebo (N=20) showed no treatment effect. Patients carrying the CC ANKK1 genotype showed no effect on treatment with disulfiram (N=18) or placebo (N=17). The GT/TT DRD2 genotype group showed a significant decrease in the number of cocaine-positive urine samples on disulfiram (N=9; 67-48%; P ≤ 0.0001), whereas the GG DRD2 genotype group showed only a marginal decrease (N=23; 84-63%; P=0.04). Genotype pattern analysis revealed that individuals carrying at least one minor allele in either gene responded better to disulfiram treatment (N=13; P ≤ 0.0001) compared with individuals carrying only the major alleles (N=17). CONCLUSION: A patient's genotype for ANKK1, DRD2, or both, may be used to identify individuals for whom disulfiram may be an effective pharmacotherapy for cocaine dependence.

Determination of disulfiram and two of its metabolites in urine by reversed-phase liquid chromatography and spectrophotometric detection after post-column complexation.

A selective method was developed for the determination of disulfiram and two of its metabolites, diethyldithiocarbamate (DTC) and copper (II) diethyldithiocarbamate [Cu(DTC)2], in complex (biological) samples by reversed-phase liquid chromatography (RP-LC) with post-column derivatization. In the first step, DTC is converted into lead (II) diethyldithiocarbamate [Pb (DTC)2] by adding lead (II) acetate. Disulfiram, Pb (DTC)2 and Cu (DTC)2 can be easily pre-concentrated on C18-bonded silica. After separation by isocratic RP-LC, derivation takes place in two solid state post-column reactors packed with metallic copper and copper (II) phosphate. Disulfiram reacts with metallic copper to form Cu (DTC)2. The same product is obtained by the ligand-exchange reaction between Pb (DTC)2 and copper (II) phosphate. Cu (DTC)2 can be detected selectively at 435 nm with good sensitivity (molar absorptivity, epsilon = 13,000). The derivatization reactions proceed rapidly and quantitatively, which was confirmed by comparison of absorption spectra. The applicability of this method is demonstrated for undiluted urine samples which, apart from the addition of lead (II) acetate and pre-concentration of C18-bonded silica, require no clean-up procedure.

Metallic copper-containing post-column reactor for the detection of thiram and disulfiram in liquid chromatography.

A reaction detector has been developed for the selective detection of thiram and disulfiram. The detection is based on the post-column complexation of these analytes on a solid-state reactor packed with finely divided metallic copper to form a coloured copper complex, copper(II) N,N-dimethyldithiocarbamate, with an absorption maximum at 435 nm. The method is combined with a pre-concentration and clean-up step on a pre-column to permit the sub-ppb determination of, e.g., thiram in surface water samples or disulfiram in urine. Separation is achieved by reversed-phase liquid chromatography.

Elimination kinetics of disulfiram in alcoholics after single and repeated doses.

Elimination kinetics of disulfiram were determined in 15 male alcoholics after 250 mg disulfiram taken by mouth as a single dose and again after 12 days of dosing. Apparent t 1/2s were calculated for disulfiram, diethyldithiocarbamate (DDTC), diethyldithiocarbamate-methyl ester (DDTC-Me), diethylamine (DEA), and carbon disulfide (CS2) and were found to be 7.3, 15.5, 22.1, 13.9, and 8.9 hr. Elimination t 1/2 for CS2 in breath was 13.3 hr. Average time to reach maximal plasma concentration after either single or repeated doses was 8 to 10 hr for disulfiram, DDTC, DDTC-Me, DEA, and CS2 in breath, while plasma CS2 concentration peaked 5 to 6 hr after disulfiram. In these studies, 22.4% and 31.3% of the disulfiram after single and repeated dosing was eliminated in the breath during one dosing interval. In urine, 1.7% and 8.3% of the disulfiram dose was eliminated as DDTC-glucuronide after single and repeated dosing, while DEA accounted for 1.6% and 5.7% of the dose. There was marked intersubject variability in plasma levels of disulfiram and its metabolites. This variability may be the result of the lipid solubility of disulfiram, differences in plasma protein binding, or the effect of enterohepatic cycling.

Proposal for the "Antabuse test".

Author describes development of the "Antabuse test" as preemployment predictive test of susceptibility of workers to carbon disulfide. He reviews all publications of his group, as well as publications of other groups on this subject. In discussion the hypothesis explaining this phenomenon is presented. Also practical suggestions for performing "Antabuse test" are mentioned.

The metabolism of 14C-disulfiram by the rat.

After administration of 14C-disulfiram to rats by stomach tube, we found that 87% of the radioactivity was excreted in urine and 7% in feces. Greater than 80% of the radioactivity was excreted by 48 hr. Small but measurable radioactivity was excreted in urine up to 144 hr after administration. Total recovery of radioactivity at 144 hr was 95% of the ingested dose with less than 1% in organs, blood, and carcass; the remainder was in urine and feces. Studies on specific radioactivity showed that diethylamine, a major urinary metabolite of disulfiram, is excreted in the urine undiluted with endogenous diethylamine. Pretreatment of rats with unlabeled disulfiram leads to a more rapid catabolism of the radioactive drug and more rapid excretion of radioactivity in the urine. Further, pretreatment appears to induce formation of a glucuronide conjugate of a disulfiram metabolite.

The effect of dietary disulfiram upon the tissue distribution and excretion of 14C-1,2-dibromoethane in the rat.

Dietary disulfiram enhances the toxicity of inhaled 1,2-dibromoethane in rats. This study was undertaken to determine whether the differential toxicity noted was associated with alterations in the levels of the compound and/or its metabolites in the target organs. A comparison of the levels of 14C in selected tissues of male rats, with and without dietary disulfiram, following the oral administration of 14C-1,2-dibromoethane was made. The results indicated that levels of radioactivity in the target organs of animals in the disulfiram group were significantly elevated both at 24 and 48 hours following compound administration. The data indicate a direct correlation between tissue levels and the enhancement of toxicity noted in the disulfiram-treated rats in the inhalation study. A significant elevation in the levels of radioactivity in washed liver nuclei obtained from animals receiving dietary disulfiram was also noted, suggesting a relationship between nuclear uptake and the increased incidence of liver tumors appearing in the disulfiran group in the inhalation study.

Radioactive and nonradioactive methods for the in vivo determination of disulfiram, diethyldithiocarbamate, and diethyldithiocarbamate-methyl ester.

Although disulfiram (tetraethylthiuram disulfide; DSF) has been used in the treatment of alcoholism for almost a quarter of a century, little is known about its in vivo metabolism. One reason for this is that few analytical methods are available that can determine DSF and its various metabolites in biologic fluids and tissues. This article describes two simple procedures for the determination of these substances.