Drug interactions in aloholism treatment

A review of the pharmacokinetics and pharmacodynamics of disulfiram and its metabolites

After ingestion, disulfiram (DSF) is rapidly converted, probably in the stomach, to its bis (diethyldithiocarbamato) copper complex. Consequently, absorption and distribution via the gastrointestinal mucosa into the blood might involve both the parent drug and its copper complex. In the blood, both compounds are rapidly degraded to form diethyldithiocarbamic acid (DDC), which is unstable and is further degraded to form diethylamine and carbon disulphide. DDC is also a substrate of phase II metabolism, which involves formation of diethyldithiomethylcarbamate (Me-DDC) and the glucuronic acid of DDC. Me-DDC also undergoes oxidative biotransformation to diethylthiomethylcarbamate (Me-DTC), which is further oxidized to its corresponding sulphoxide and sulphone metabolites. Me-DTC may to act as a suicide inhibitor with a preference for the mitochondrial low Km isozyme of aldehyde dehydrogenases (ALDH 1), whereas the two S-oxidized metabolites, especially the sulfone metabolite, are more potent inhibitors not only of ALDH 1, but also of the cytosolic high Km isozyme of ALDH (ALDH 2). The inhibitory reaction between the enzyme and each of the three metabolites is characterized by a covalent adduct formation, probably with the cysteine residue at the active site of the enzymes. The adduct formed is nonreducible at a physiological concentration of glutathione, and inactivation in the presence of this endogenous tripeptide was increased by action in vitro of the sulphoxide and sulphone metabolites. Those findings are all in concordance with the in vivo observations made on DSF. In human volunteers treated with increasing doses of DSF and challenged with ethanol between each of the dosage periods, the mean plasma concentrations of Me-DTC at steady state were proportional to the DSF doses given. There was also a close relationship between increased oxidative metabolic formation of Me-DTC, high oxidative formation of acetaldehyde, and the full complements of a valid disulfiram ethanol reaction (DER). Consequently, Me-DTC in plasma may not only serve as a marker of the oxidative metabolic function of the liver, but also of the therapeutic effectiveness of the treatment in subjects at steady state. Obviously, there is a need for individual dose-titration regimens. In patients with alcohol-related severe hepatocellular damage, the oxidative P 450 catalyzed formation of the Me-DTC and probably also of its sulfoxide and sulphone metabolites is impaired, and thus inactivation of ALDH activity in the liver appears to be delayed or even completely absent. The consequence for the patient may be an insufficient DER.(ABSTRACT TRUNCATED AT 400 WORDS)

Disulfiram treatment of patients with both alcohol dependence and other psychiatric disorders: a review

In treatment of alcohol dependence, disulfiram is most useful in conjunction with a structured, supervised, aftercare program. However, it has been reported to cause psychiatric side effects and to interact with various psychiatric medications. Many patients with alcohol dependence suffer from other psychiatric disorders and are treated with such psychiatric medications. This paper reviews the pertinent clinical pharmacology of disulfiram and the literature on potential psychiatric complications and drug interactions of disulfiram. At the usual dosage, about 250 mg/day, disulfiram does not appear to increase significantly the risk of psychiatric complications or of psychiatric drug interactions. Therefore, it can be considered a treatment option for patients with alcohol dependence and other psychiatric disorders.

The clinical use of disulfiram (Antabuse): a review

Disulfiram is a potent alcohol-sensitizing drug, the effectiveness of which remains unproven in the treatment of alcoholism after 40 years of use. Its clinical utility is more closely associated with nonspecific, nonpharmacological factors (such as social class, patient compliance, patient personality characteristics, and treatment structure) than with its aversive biochemistry. Disulfiram is not effective as a sole alternative to a structured treatment program. Disulfiram retains a place in standard alcoholism treatment programs because clinicians have found this agent useful for selected alcoholic patients. Clinical studies and clinical lore describe these patients as older, relapse-prone, socially stable, cognitively intact, not depressed, compulsive, capable of following rules, and tolerant of dependence. Another distinctly responsive (but evasive) group is court-probated patients. These characteristics also describe patients who are well-known to have good outcomes without disulfiram, thus they do not help clinicians to select suitable patients for this medication. Consequently, this article proposes the following selection criteria: (1) patients who can tolerate a treatment relationship; (2) patients who are relapse-prone (but in treatment); (3) patients who have failed with less structured approaches; (4) patients in early abstinence who are in crisis or under severe stress; (5) patients in established recovery for whom individual or group psychotherapy is a relapse risk; and (6) patients who specifically request it. With or without disulfiram, a treatment program needs to be highly structured and predictable in order to be useful to newly recovering patients. Recovery is a process with discernible phases of development, and the provision of structure is the core of early treatment, where behavior change is more important than insight. A well-structured program will have phases through which a patient may progress. Generally speaking, disulfiram is most useful early to establish sobriety and to allow time for other support structures, such as AA, therapist-patient relationships, and new personal relationships, to take hold. Disulfiram is best given to patients with prior treatment failures, early in treatment, briefly during crises in established sobriety, or to support unusual stresses, such as psychotherapy. Prescriptions should be short-term and not allow automatic refills. It should be necessary to attend a treatment program in order to obtain them. Supervision and monitoring dramatically increase compliance.(ABSTRACT TRUNCATED AT 400 WORDS)

The disulfiram-alcohol reaction: factors determining and potential tests predicting severity

13 ambulatory alcoholics (3 women, 10 men) who consented to alcohol-aversive treatment with disulfiram were subjected to detailed investigations before, during, and after the disulfiram-alcohol reaction (DAR). The studies included quantitative estimation of liver function (aminopyrine breath test, ABT; galactose elimination capacity, GEC) prior to the DAR, measurement of alcohol and acetaldehyde plasma levels together with pulse rate and blood pressure during the DAR, and the effects of disulfiram on erythrocyte acetaldehyde-oxidizing capacity (AOC). As expected, the severity of the DAR showed considerable interindividual variation. However, the maximal fall in diastolic blood pressure was closely (r = 0.83; p less than 0.001; n = 13) related to peak acetaldehyde plasma level (AAPL). The decrease in systolic blood pressure was age dependent, individuals greater than 40 years exhibiting a larger drop for a given AAPL. The dependence of acetaldehyde formation on liver function was suggested by a significant correlation (r = 0.88; p less than 0.01; n = 8) between ABT and AAPL; this relationship was influenced by the prior intake of enzyme-inducing drugs. Measurements of AOC indicated that a disulfiram-induced maximal suppression is achieved already after 6 days of treatment reaching levels of 0.7 +/- 0.6 nmol/ml/min (SD) (compared to pretreatment values of 4.1 +/- 0.9). Mean values in untreated alcoholics and in subjects with alcoholic or nonalcoholic liver disease were not significantly different from controls.(ABSTRACT TRUNCATED AT 250 WORDS)