Ask a Doctor: Smoking pot, painkiller for the patient and headache for the doctor


Editor’s Note: Our doctor in residence, Dr. Mailis Gagnon, advises us that this is to be the first of a series on the topic of marijuana and its medical uses. 

I had made every effort to avoid dealing with this topic in my articles, as it is too hot and truly too messy. However, the issue has become so current that I cannot help but to report on it. Is pot useful in treating chronic pain? And if so, how does one get a prescription for medical marijuana?

First, let’s talk a little bit about history (I am using excerpts in quotations from my book BEYOND PAIN with David Israelson written exactly 10 years ago in 2003):

“The cannabis sativa L or hemp plant was one of the first plants to be used by man all over the world to create fibres, food and medicines and in social and religious rituals. In most fibre-producing areas the plant is used only for the manufacturing of clothes and ropes. Cannabis was used by the Yellow Emperor Huang Ti  (around 2600 BC) for its medicinal and mood altering effects and as an anesthetic in wine for major operations around the 3rd century AD. It was also used by the Assyrians, the Sumerians and many other ancient civilizations for pain, inflammation, epilepsy and various other diseases.  Historically, in India, the plant was used both medically and non-medically. On few social occasions, the weaker preparation of the plant called “bhang” (comparable to marijuana) was taken by mouth, while slightly stronger preparations (“ganja”) were smoked. Hashish, the strongest preparation of all, was used in the Middle East and Asia, but like marijuana itself, its use has long been controversial. Known as “charas” in India, it was not socially approved there for any purposes and those who used it were regarded as “bad people” or outcasts. When it comes to pain, cannabinoids were used by ancient populations thousands of years ago, by Asian populations in the Middle Ages and for various pains in the West during the 1800s, with commercial preparations supplied by the pharmaceutical company Lilly and Squibb. Cannabinoids were subsequently discontinued as medical agents in the 1930s. It was only in 1964 that the sole psychoactive ingredient of cannabis, Delta 9 -THC, (tetrahydrocannabinol), was isolated in pure form. The discovery of morphine receptors in the brain and the spinal cord in the 1970s led to the discovery of endorphins, the body’s own pain killers. Similarly the discovery of cannabinoid receptors in the brain (CB1) questioned whether the brain produces marijuana-like substances as well. Indeed, two such internally produced compounds, called “endocannabinoids”, were discovered. After that discovery, synthetic cannabinoids were created, some of which have other than psychoactive functions.

Today, synthetic cannabinoids are in use to increase the appetite of patients with AIDS and for prevention of vomiting and nausea in cancer patients who are undergoing chemotherapy. Cannabinoids seem to have protective effects on nervous tissues, and may work on inflammation, anxiety and several other conditions.

Numerous animal experiments so far show as well that cannabinoids can block many different kinds of pains. A very interesting aspect of cannabinoids is their potential to help other drugs work better. For example, L-DOPA, a drug used in Parkinson’s disease, works much better in people when combined with apomorphine, a cannabinoid”.

Some cannabinoids are commercially available in the form of pills dronabinol (commercially known as Marinol in Canada and elsewhere) and nabilone (known as Cesamet) as well as a spray (Sativex). Unfortunately, the use of pills is problematic as they are absorbed slowly and unpredictably. Currently, the major debate in medical and political circles relates to the question of whether smoking marijuana for medical reasons should be permitted. We know that smoking in general carries major risks for inflammation of our lungs and lung cancer.  It was on this basis that in 1999, the U.S. National Academy of Sciences Institute of Medicine, recommended that therapeutic uses of smoked marijuana be highly regulated and reserved for “dire circumstances”.

Major reviews of the potential therapeutic actions of cannabinoids have been conducted in Great Britain, Australia, and the United States, and all have concluded that smoking marijuana should be permitted under special circumstances, such as when patients are terminally ill, or in other cases for limited amounts of time. All suggest research into alternative methods of administration of the active ingredients in marijuana for rapid action without the risks associated with smoke inhalation. There is, however, universal agreement that cannabinoids have special actions against nausea, vomiting, lack of appetite, pain and spasticity etc. However, most medical communities feel that proper studies need to be done before the general use of cannabis or cannabinoids was to be recommended.

The legal issues that are involved with smoking medical marijuana:

THEN: On July 30, 2001, following a highly publicized Supreme Court of Canada case, the federal government hastily established a set of Marijuana Medical Access Regulations. These regulations spelled out three categories of people who could apply to possess marijuana for medical reasons:

  1. People who suffer from a terminal illness and are doomed to die within 12 months;
  2. Those who suffer from specific symptoms such as pain, spasms, nausea and so on which are related to particular diseases such as Multiple Sclerosis, spinal cord diseases, AIDS or severe arthritis, provided that all other available treatments have been tried or found not to be appropriate;
  3. An all-inclusive “non-of-the-above” category, consisting of those suffering from conditions other than those mentioned above, provided again that all other treatments have failed. Patients in group #2 used to require a declaration from one medical specialist. Patients in group #3 needed declarations from two doctors. A many pages long form, could be obtained from the Health Canada website as well as a guide with regulations and explanations for the application process, so patients could either grow their own marijuana or find someone to grow it for them.

For the first time in 2001, Canadian doctors were asked to prescribe a drug for which there was no written information, indications, contraindications, dosages and so on. When they signed the requested form, they were asked to acknowledge that they knew that the drug has not been tested for safety and effectiveness. They also had to declare that “the benefits … outweigh any risks associated with its use”. The professional associations of the medical doctors across Canada stated clearly their concerns. Nevertheless, from 2001 to now, about 30,000 patients had been receiving medical marijuana across the country.

NOW: Early in 2013, Health Canada announced big changes to the country’s medical marijuana rules. In a nutshell, a) the option for patients to grow their own pot was revoked, and they must now acquire their marijuana from a designated provider, and b) the requirement that Health Canada approves the use of medical marijuana was lifted. Before, doctors had to fill out a very lengthy form to be forwarded to Ottawa for Health Canada to grant final approval. Now, a doctor’s simple script that medical marijuana could be beneficial, would be enough.

Well, what do doctors feel about these changes? What are patients supposed to do? Read my next article on the subject to find out!


Angela Mailis Gagnon, MD, MSc, FRCPC(PhysMed)

Director, Comprehensive Pain Program,

Senior Investigator, Krembil Neuroscience Centre

Toronto Western Hospital,

Chair ACTION Ontario