26th July 2005
Richard Hallinan and Andrew Byrne, Redfern Dependency Practice
Richard Hallinan and Andrew Byrne, who are both committed to best practice in dependency medicine, presented this useful seminar on benzodiazepine use. The session began with an overview of the pharmacology of benzodiazepines, and some relevant comparisons were made with alcohol, opiates and major tranquillisers. Differences between the various benzodiazepines particularly in relation to half-lives were outlined, and indications, side effects, tolerance and withdrawal were all discussed. A handout was available detailing all of these points.
Special mention was made of benzodiazepine (BZD) use by patients on methadone maintenance treatment (MMT) and it was noted that this group of people often have particularly high levels of psychopathology and psychosocial distress, including higher rates of unemployment, incarceration, HCV, and HIV/HCV risk-taking behaviour. BDZ users on MMT also tend to be on higher methadone doses and to have higher blood levels, although methadone concentrations adjusted for dose are actually lower in this group. The reason for this is unclear as there is no evidence that diazepam increases the clearance of methadone. One hypothesis is that there is a tendency for rapid methadone metabolisers to seek BZDs, in which case split methadone dosing might be useful. It may also be that these people are self-medicating, or "just can't get enough of a 'good' thing".
An approach to BZD abuse in MMT patients was outlined. It was suggested we make sure that psychopathology (eg anxiety and depression) is adequately treated, alcohol problems are addressed and information obtained from the Doctor Shoppers Hotline in appropriate cases. Consideration should be given to moving from short to long acting forms of which diazepam is the most common. Also, supervised dispensing should be considered where 'control' or impulsivity are problems. It is also essential to optimise the methadone dose, being flexible about dosing times or, occasionally, split-dosing (which needs prior approval from the PSB).
Reasons for BZD use were outlined, and are important to understand when looking at treatment options. People take BZD for many reasons, including alleviation of anxiety and insomnia, self-medication of depression, self-medication of withdrawal from opiates and BZDs, to come down off stimulants, and to get an increased "buzz". So-called "Poly-drug users" swap from one drug like speed or heroin to another such as BZD, and may simply do this because BZDs are the cheapest or most available drug at the time. It was noted that BZDs in Australia are subsidised on the PBS, whereas they are very expensive and hard to obtain in the U.S. so it is no surprise that their use amongst the marginalized in the USA is far less.
Aims of treatment of BZD dependence were clarified within the overall context of harm reduction goals. This includes abstinence and it was pointed out that harm reduction has sometimes erroneously been seen to include legalizing drugs, which while worthy of discussion, is quite a separate issue. Our first dictum should be "Do No Harm" and we shouldn't forget that an important part of this is just saying "no" when appropriate.
When assessing a patient for treatment we need to understand their personal history of abstinence, by asking questions such as "when were you last abstinent?", "how many times have you achieved abstinence?", "how did you become abstinent?", and "what did it feel like when you were abstinent?". We need to understand that previous abstinence may not necessarily have been a happy and stable time for every patient.
It was pointed out that the statistics regarding measurement of harm relating to BZD use are limited, but nonetheless worrying. Doctors must weigh the harms and benefits of BZDs both in the community and in individuals (as we do with all other prescribing). PBS prescribing figures reached a peak in 1988 and have fallen since then. It is well accepted that some people function well on a small dose of diazepam, so this drug may have a useful place in legitimate treatment plans. It is gratifying that in Australia, appropriate regulation has seen the end of temazepam capsules, along with Mandrax (methaqualone and diphenhydramine), meprobamate (Miltown), bromides, barbiturates and high dose flunitrazepam, which have all vanished from scene.
Harm from BZD dependency was discussed, and includes an array of physical, social and behavioural disturbances. Special mention was made of the damage to nerves and blood supply when subjected to pressure for prolonged periods of time. This scenario can occur with overdose and increased use which leads to long periods of reduced consciousness in fixed positions. Nerve palsies, skin necrosis and the compartment syndrome can occur. Thrombosis and infections from injecting, criminal activity including prescription fraud, convulsions from withdrawals, and deepening of depression are all possible consequences of BZD use. Rates of domestic violence are probably parallel with alcohol abuse.
Treatment approaches to BZD use rely on an accurate diagnosis, which should depend on a detailed history with relevant physical examination. Urinary drug screening can be useful, along with information from pharmacists and reports from HIC services. Some unusual features of benzodiazepine users were noted, including possession of a Medicare card with a high terminal digit (8 or 9), fiddling with the position of furniture within the consulting room, talking to the GP with great familiarity and requesting the drug by specific name. The assessment of BZD use should parallel that which is done for opiate users, including the level of dependence and addressing resultant medical and social harms. Co-existent mental health issues should be treated and methadone treatment at optimal dosage. As with all other drug use, there is a spectrum of patterns of use, including non-dependent occasional use, irregular binge use, dual dependency (eg with opiates) and "pure" BZD dependency. It may be useful for the patient to keep a drug diary, as memory may fail in this patient group.
If considering regular prescribing of BZD with a view to abstinence, there are some useful "check-list" questions we can all ask ourselves. They include: "What alternative strategies has the patient tried?", "have I seen their drug diary?", "what is their motivation for abstinence?", "have I seen a UDS result?", "have I sought information from the HIC hotline?", "are they on optimum doses of methadone or pain treatment?", "is treatment for mental health conditions adequate?"
Prescribed BZD must be tailored for the individual, but it was emphasized that slow reductions in doses may take months in established dependency. It is unrealistic to expect a patient with long-term BZD dependency to be able to maintain abstinence following a 2-4 week reduction regime. Diazepam is the preferred BZD to use for reduction regimes owing to its long action and familiarity. Several case histories were discussed to help illustrate management plans.
Australian Health Insurance Commission (HIC) services were also discussed. There are two separate services: firstly, "Prescription Shopping Information Service". Doctors must first register if they wish to access any information. Doctors are given a PIN number, and can find out information on numbers of BZD PBS prescriptions and numbers of doctors seen, above a certain threshold. No information is kept on private prescriptions. Toll-free phone is 1800 631181. The second HIC service is a "voluntary agreement" print-out of PBS items available after the patient signs the consent form. Forms available from 1800 420074. These services may be useful not only because of the information they provide, but because patients know their doctors can access certain information about their BZD use.
The meeting ended after some complex but somehow familiar case histories with lively discussion about the various possible approaches.