Morphine in drug treatment
Morphine is not licenced for the treatment of addiction but is used for that purpose in the UK and some other jurisdictions. The half-life of morphine is short and morphine usually needs to be taken four hourly. There are slow release formulations available which address this problem but as ever with short acting opiate agonists dose levels are problematic. Many prescribers are nervous about exceeding the dose levels cited in the British National Formulary which refer, for drugs under the ‘Analgesic’ heading, to pain relief. Although many patients are seeking relief from chronic pain they are unlikely to have the same expectations of their medication as users with a background of heroin dependence whose histories, motivations and needs can be extremely complex. The DH guidelines produced for GP’s (and all doctors) say methadone and morphine are dose equivalent at 1mg: 1mg, but this ignores the fact that the half-life of morphine is about 1/8th of that of methadone. This means to reach a meaningful dose equivalent you would need to multiply morphine dose by about 8. (‘The Handbook of Clinical Drug Data’ suggests 1mg of methadone = 10mg of morphine over 24hrs). This means that a client on 100mg of methadone will require something like 800–1000mgs of morphine a day. A figure that frightens prescribers as it seems like a colossal amount of a drug with ‘clear abuse potential’. This stated however, in a market dominated by other licit and illicit opiates/opioids, the role of morphine itself, is decidedly subsidiary.