Cancer news
Cannabis-based spray painkiller approved for cancer patients
ANDRÉ PICARD
From Wednesday’s Globe and Mail
August 8, 2007 at 3:31 PM EDT
Health Canada has approved a new cannabis-based painkiller to help alleviate the suffering of cancer patients.
The drug, sold under the brand name Sativex, is administered by spraying it into the mouth. It is intended to be used by cancer patients suffering from neuropathic or nerve pain, which is excruciating and difficult to control.
“It’s an adjunctive treatment, an add-on. You take it in addition to opioids (such as morphine),” Allan Gordon, director of the Wasser Pain Management Centre at Mount Sinai Hospital in Toronto, said in an interview.
“It will be helpful as another way to reduce pain,” he said.
Dr. Gordon said that 60 to 90 per cent of people with advanced cancer experience significant pain and there are far too few pain-relief options available to them.
He estimated there are at least 100,000 Canadians with cancer who are dealing with severe pain at any time.
“There’s an unmet need there and finally we’re seeing some attention being paid to the problem,” he said.
While Sativex contains the active ingredients that give pot smokers their buzz, including delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), users are unlikely to get stoned. When people are in severe pain, the drug provides relief rather than pleasure, much like opium and heroin used medicinally.
Each spray delivers a fixed dose of 2.7 milligrams of THC and 2.5 mg of CBD. Patients can control the number of doses, but it is recommended they not exceed 14 sprays daily.
“We have to reference this drug as a pain-management therapy. It’s not a recreational vehicle,” Dr. Gordon said.
He also noted it’s an expensive and inefficient way to get high compared with smoking marijuana or hashish.
Sativex, by U.K.-based GW Pharmaceuticals, is marketed in Canada by Bayer Inc.
The drug costs roughly $125 per vial (prices vary by province and do not include dispensing fees). Each vial contains 51 sprays. The average daily dose is five sprays, which translates into an average cost of about $12.25 a day. The prescription drug is covered by most private insurance plans, but not yet by any provincial drug plans.
In 2005, Canada became the first country in the world to approve the sale of a prescription painkiller derived from cannabis. Sativex was initially allowed on the market for the treatment of severe pain associated with multiple sclerosis.
It belongs to a class of drugs known as cannabinoids. A report issued yesterday said the sale of cannabinoids has soared by 45 per cent worldwide in the past year, to $709-million (U.S.)
In addition to Sativex, the class of drugs includes Rimonabant, a high-profile anti-obesity drug from Sanofi-Aventis, along with Marinol and Cesamet, drugs used to treat nausea and vomiting in cancer patients undergoing chemotherapy.
Scientists are excited by the prospect of this class of drugs because there are about 10 times as many cannabinoid receptors in the brain as opioid receptors, meaning the drugs should be more effective at blocking pain.
Cannabis-based drugs also appear to have fewer side effects than those derived from opium. Some users of Sativex complain that the spray leaves an odd taste and can cause minor gastrointestinal problems. Drugs such as codeine and morphine, on the other hand, can cause severe constipation and drowsiness. Many physicians also hesitate to prescribe opioids because they are highly addictive.
An estimated 159,000 Canadians will be diagnosed with cancer this year, and 72,700 will die of cancer in 2007, according to the Canadian Cancer Society.
