Difficulties in a clinical application of methadone-dose contingency contracting

We review outcome of 14 methadone-maintenance patients who were offered a choice of administrative discharge or a methadone-dose contingency contract for continued drug abuse. In the three months before intervention, only 38% of urines were drug-free, while 55% were drug-free during the three-month intervention. Marked improvement occurred during the first month, while later the effect faded. Nine patients discontinued or reduced drug abuse, arriving at stable or fluctuating dose, and did not detoxify. Five others continued drug abuse, eventually reducing their methadone doses to zero. The procedure at least temporarily reduced drug abuse among the former group, but lack of uniformity in applying contingencies may have weakened the effect. Considering the spreading AIDS epidemic, we review the confusing literature on management of still-abusing methadone maintenance patients and suggest a protocol for their treatment.

Urine screening for abused drugs in new admissions to a VA hospital

The urine samples from two groups of Veteran's Administration patients newly admitted to general psychiatry units were screened in 1985 and in 1987-88 for abused drugs. The results were compared with urine samples from controls with similar age distributions admitted to an alcohol and drug abuse unit or to medical-surgical units. About 40% of all newly admitted patients were positive for one or more controlled drugs, but there were no significant differences among patient groups in the percentage of urine samples positive for these drugs. Marijuana and benzodiazepines were detected frequently in all patient groups and often in combination, although opiates also were frequently detected in the urine samples from the medical-surgical patients. There was a clear decrease in drug-positive samples with age in all patient groups, much of which could be accounted for by decreased marijuana detection.

Antenatal urinary screening for drugs of addiction: usefulness of sideroom testing?

Based on a pilot study of 400 samples at our Antenatal Clinic (which yielded 3.5% positives when assessed for amphetamines, cannabinoids and opiates) 600 consecutive patients attending Antenatal Booking Clinic had urine samples tested in the sideroom for amphetamines, barbiturates, cocaine metabolites, methadone and opiates using the Syva EMIT ETS apparatus. Positive samples were checked in the West Midlands Regional Laboratory for Toxicology, initially by EMIT-dau on a second ETS instrument and then by thin layer and gas chromatography. Two per cent produced a total of 14 positive EMIT results. Cocaine metabolites and methandone were not detected. Four specimens could not be confirmed as positive. In one sample, amphetamine-like compounds were isolated but not identified. Positive identification was made in the remaining seven specimens (two cannabinoid, two pseudoephedrine, one pseudoephedrine plus dihydrocodeine and two dihydrocodeine). There was a serious problem of false positive results observed in the initial sideroom testing. The value of sideroom testing for drugs of abuse was assessed in relation to the technical problems and to the small rate of drug positive samples.

Clinical pharmacokinetics of non-opiate abused drugs

The present review discusses the available data on the kinetic properties of non-opiate abused drugs including psychomotor stimulants, hallucinogens and CNS-depressants. Some of the drugs of abuse reviewed here are illicit drugs (e.g. cannabis, cocaine), while others are effective pharmacological agents but have the potential to be abused (e.g. benzodiazepines). Although some of the drugs mentioned in this review have been in use for centuries (e.g. caffeine, nicotine, cocaine, cannabis), knowledge of their kinetics and metabolism is very recent and in some cases still incomplete. This is partially due to the difficulties inherent in studying drugs of abuse in humans, and to the complex metabolism of some of these drugs (e.g. cannabis, caffeine) which has made it difficult to develop sensitive assays to determine biological pathways. Although drugs of abuse may have entirely different intrinsic pharmacological effects, the kinetic properties of such drugs are factors contributing to abuse and dependence. The pharmacokinetic properties that presumably contribute to self-administration and drug abuse include rapid delivery of the drug into the central nervous system and high free drug clearance. Kinetic characteristics also play an important role in the development of physical dependence and on the appearance of a withdrawal syndrome: the longer the half-life, the greater the likelihood of the development of physical dependence; the shorter the half-life, the earlier and more severe the withdrawal. The balance between these 2 factors, which has not yet been carefully studied, will also influence abuse patterns. The clinical significance of kinetic characteristics with respect to abuse is discussed where possible.