Tues 23 Sept 03
Professor Robyn Richmond. "Smoking cessation in dependency patients. What is best practice?"
Dr Richard Hallinan "Therapeutic thresholds in methadone maintenance: resolving the debate over blood levels".
Chair - Dr Bob Elliott.
We had another informative session at the September Concord dependency seminar when Professor Robyn Richmond from UNSW gave us a preview of the new general practice smoking cessation guidelines and their genesis. She reminded us of the prevalence of smoking in Australians at around 20% of the population, one of the lowest rates in the world. Despite very high smoking rates in the 1950s to 1960s, Australia succeeded in reductions with a combination of advertising bans, education, price policy and treatment availability. Yet smoking is still the biggest cause of preventable pathology and premature deaths in our population.
Around a third of smokers do not want to address their dependency and are 'pre-contemplators' regarding abstinence programs. But this still leaves a substantial proportion of smokers who are amenable to intervention. We now know from careful research that 'brief interventions' actually succeed in terms of yielding more non-smokers in 6 to 12 months, especially when there is active follow-up (see this week's MJA on the subject). General practice is one of the few places where 'opportunistic' interventions such as this can be done when smokers attend for a variety of other reasons, usually unrelated to tobacco addiction.
Professor Richmond told us that good statistics are now available for tobacco use as well as responses to the various evidence based interventions which are being promulgated in the new National Guidelines. On average, about 40% of 'successful' quitters will have taken up the habit again by one year. This emphasises the importance of follow up and preventive measures. We were told that although they may help some people, non-evidence based treatments such as acupuncture or hypnotherapy will not be included in the current guidelines.
As doctors, pharmacists and other health care workers, we were encouraged to inform all our smokers that help was available when they were ready to quit using nicotine replacement therapy (gums and patches) and buproprion tablets (Zyban). Professor Richmond said that there are some new 'commercial in confidence' drugs on the way and we should have even more modalities in the coming years. Nicotine patches can become a longer-term habit in about 10% of cases but this was thought to be overshadowed by the great benefits of the others who often manage to become abstinent for long periods, or even permanently.
We were advised to address smoking from the individual's perspective and ask what people actually found positive and pleasurable about smoking and what they found negative such a cost, health consequences, halitosis, etc. This allowed the patient to focus and reflect on their own habit and its consequences. Some anatomical photographs of lung cancer cases, blocked arteries, etc made good theatrical props and will be included in the package to GPs which are now being trialled.
In the second half Dr Richard Hallinan spoke of taking a history, examination and, occasionally, blood testing for detecting fast metabolizers in methadone maintenance therapy. He spoke of Professor Chin Eap's masterly review of the subject and his finding of a 'threshold' for blood levels which was consistent at around 0.4mg/l. Above this level regular heroin use is exceptional, making dose increases a serious option for those with lower levels, given that there is no clinical toxicity.
Dr Hallinan brought us face to face with a large group of published research relating to the absorption, portal availability, protein binding, hepatic and other metabolism and excretion of methadone. He pointed out the differences between methadone and many other drugs we use in medical practice as well as some of the similarities. He is presently working on a study of left and right stereoisomers of methadone (to use outdated terminology) and will bring us up to speed on that subject, including the new terms at the next seminar.