PATIENTS in Britain's first clinical trial of cannabis will take the drug through an inhaler similar to those used by asthma sufferers.

The device, to be unveiled this month, will use vapours from heated cannabis aimed at giving quick pain relief to hundreds of multiple sclerosis, neuralgia and glaucoma sufferers taking part in the trial. The cannabis, a brown viscous liquid, will be heated in a laboratory oven and placed in the inhaler, the size of a mobile phone. The patient will inhale the vapours through a tube under medical supervision. Pain relief is expected in minutes. Eventually, it is planned the heating mechanism will be incorporated into the inhaler.

The drug, which produces an analgesic effect in small quantities and a "high" in larger amounts, is only activated when heated. It is hoped that the trial, involving 900 patients over a three-year period, will begin in July, subject to approval by the Medicines Control Agency. One hundred patients are being selected for the early stages.

Most patients will be MS sufferers but there will also be people with neuralgia, glaucoma and post-operative pain. The dosage will be large enough to relieve pain but not enough to make them "high". If the drug is shown to ease symptoms without side-effects, doctors could be prescribing it to some of the country's 85,000 MS sufferers within five years.

Inhaler technology has existed for some years but GW Pharmaceuticals - which is conducting the trial - has been working with the manufacturers for a year to adapt it for cannabis use. Mark Rogerson, a spokesman for GW Pharmaceuticals, said: "The most important thing is being able to replicate the beneficial effects of inhaling cannabis without the harmful effects of smoking and that's why so much effort has gone into making this inhaler."

(Source: The Daily Telegraph Sunday, June 13 1999)