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Recent developments in treating opiate misuse

Clare Bellingham examines recent developments in the use of buprenorphine, methadone and naloxone

On April 1, it became possible for buprenorphine to be prescribed and dispensed by instalments for the treatment of drug addiction in England. The change in regulations permit the prescription of buprenorphine on FP10HP(AD) pink forms and FP10MDA blue forms. Buprenorphine had been previously excluded from being prescribed on these prescription forms because it is a schedule 3 Controlled Drug (CD) and the forms are used for prescribing schedule 2 CDs. Buprenorphine is now the first schedule 3 CD to be prescribable on these forms. In a letter sent to pharmacists in March, the Chief Medical Officer (CMO) and Chief Pharmaceutical Officer (CPO) say that randomised controlled trials have demonstrated an efficacy for buprenorphine comparable to that of methadone for management of opiate dependence. The only licensed product containing buprenorphine for management of opioid dependence is Subutex. The letter from the CMO and the CPO advises that, when a patient collects the first instalment of buprenorphine, a patient information leaflet should be supplied to give advice on how to use the product, special warnings, precautions and drug interactions. The letter stresses that Temgesic, the other marketed product that contains buprenorphine, should not be supplied for substitution treatment of opioid dependence. It is not licensed for this use and therefore the patient information leaflet is inappropriate. In terms of payment, buprenorphine will continue to attract an additional fee of 43p for a schedule 3 CD which will be paid for each instalment dispensed. The change in regulations allowing buprenorphine to be dispensed in instalments was made following advice from professionals in the substance misuse field and recommendations in “Drug misuse and dependence — guidelines on clinical management”. The change has been made in England and is expected to be made shortly in Wales. In Scotland, buprenorphine can already be dispensed in instalments. A study published earlier this year suggests that buprenorphine is a safer alternative to methadone. Deaths attributable to buprenorphine and methadone were compared in France from 1994 to 1998. The yearly estimated death rate related to methadone use was found to be at least three times greater than the death rate related to buprenorphine. In France, buprenorphine is widely used by general practitioners as an alternative to methadone, which is only available in specialised treatment centres. Between 1994 and 1998, 14 times as many patients received buprenorphine than methadone (Journal of the American Medical Association 2001;285:45). Expanding methadone schemes Meanwhile, a pharmacy in Chesterfield has been specially designed and refurbished to offer a supervised methadone scheme. It has been set up at Boots the Chemists following funding and support from local agencies. Graham Archer, store manager, said: “Funding from Chesterfield's Drug Action Team helped to provide a more tailored environment to meet the needs of our rehabilitating patients.” The refurbished pharmacy contains an area with a hatch into the dispensary that is screened in a manner similar to a polling booth. Patients collecting methadone can enter the private area, talk to the pharmacist at the hatch and consume their dose of methadone without being seen by other customers in the pharmacy. “The main driver for Chesterfield's need for a supervised methadone service was to inhibit 'leakage' of prescription methadone,” Mr Archer said. The local health authority helped to develop the protocols for the service and is involved in evaluating the success of the scheme. This would include pharmacists making reports of missed or refused doses, for example, he added. In addition, supervised methadone schemes offered greater opportunities to monitor drug interactions, adverse reactions, well-being of the client, provision of information and advice, referral to other drug treatment services, and monitoring of over-the-counter items that might be abused. The scheme has only just opened and, so far, has three regular patients having daily supervised doses. It has a capacity for more patients and the company hopes that usage will expand. The scheme had the potential to be rolled out not just in Boots but wherever the physical environment and local health authority support allowed it, a Boots spokeswoman said.   “Take home” naloxone saves lives Studies have revealed that supplying opiate users with naloxone to treat other users who overdose saves lives. Preliminary results from two pilot studies in opiate users published this week are encouraging. “No adverse effects have been reported and 10 per cent of the distributed naloxone has saved lives,” researchers conclude. The idea could potentially be broadened to include training family members living with opiate users to administer naloxone in overdose situations. In one study, based in Berlin, opiate users were given training in emergency resuscitation after overdose and a supply of two 400µg ampoules of naloxone, needles and syringes. After 16 months, 124 opiate misusers had received the training and naloxone supplies. Of the 124, 22 had given emergency naloxone on a total of 29 occasions. Resuscitation occurred at home in 59 per cent of cases, and outdoors, including parks and public toilets, in 38 per cent of cases. Naloxone was given intramuscularly in 48 per cent of cases, intravenously in 45 per cent of cases and subcutaneously in 7 per cent. The researchers comment that some casualty departments and ambulance services recommend giving naloxone intramuscularly or subcutaneously rather than intravenously because it can be given more quickly and results in a less vigorous recovery. Administration of naloxone was judged to be appropriate in 90 per cent of cases. In the others, it was of uncertain benefit where the situation was not life-threatening and pointless in one incident of cocaine overdose. All 29 people who received naloxone recovered. In 34 per cent, a sudden onset of opiate withdrawal occurred. In the second pilot study, 101 drug misusers were supplied with a minijet ready filled with 800µg naloxone during a 16-month period. Five instances of resuscitation using naloxone were reported and all patients recovered fully. The researchers comment that the range of doses given in the Berlin project (from half an ampoule to two ampoules) raises the possibility that naloxone was being titrated to effect resuscitation without provoking withdrawal. If this is the case, recovery would need to be monitored to avoid subsequent relapse into overdose, they argue (British Medical Journal 2001;322:895).

Clare Bellingham is on the staff of The Pharmaceutical Journal

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