Medical Marijuana: Benefits and Costs

I recently gave a presentation on this subject to the American Osteopathic Association’s Research Conference in San Francisco. (I am writing this before the election, so I don’t know if the legalization measure passed.)

Medical Cannabis (MC) has been used for over 4,600 years for many reasons. I have never used it but I read a lot and talk with patients. The plant has over 60 cannabinoids (THC-related compounds) and over 100 terpenes (another compound that may have some effects). Each of these can individually affect the body or one can influence the other, i.e. the proper mix is what may be important.

There are at least two receptors in the body, CB1 and CB2, which are acted upon by MC. Just like we make our own morphine-like compounds (endorphins) we make our own cannabinoids but we know less about them than we do about endorphins which rise up when we do certain activities. Some feel high from their endorphins after running for 20 minutes, playing futbol, riding a roller coaster, or seeing a scary movie.

There have been many research papers discussing MC and the last few years have seen quite an increase every year. The US government restricts physicians and scientists from researching it since they feel it is as bad as heroin (a schedule 1 drug). The government only has paid for research to find what is wrong with MC rather than what is good about it. They typically use doses in animals over 100 times what a regular MC user would use, so no wonder they find bad side effects. Most of the research into the benefits has been performed in less restrictive countries. The government supplies a very weak grade of MC for some studies in humans so that makes it hard to find a benefit also.

In 1996 the California voters passed a law allowing MC to be used for certain conditions. Certainly there has been abuse of this law but many ill people have received relief of serious symptoms, better than what other medications could offer. The state has a form on their website for the physician to fill out to recommend use of MC and then the patient follows the rules their county has set up for their ID card. San Bernardino and San Diego were the last counties to get this process in order after multiple court rulings forcing them to. I was on the San Diego City committee to make this process work smoothly. At the county hospital where I work, there is still no policy for me to write the recommendation letters, so I don’t.

Patients make or buy products to help their symptoms. The MC can be dissolved into fat—butter, cake frosting, brownies, salad oil–but the onset of action is delayed and prolonged so the dosing is hard to adjust well.

The MC can be burned in a joint to use just enough puffs to get the benefit and avoid the side effects. A bong filters out the ash and the large molecules. A vaporizer can be used which doesn’t burn all the compounds so a lower dose may be used and the MC will last more days.

Sativex is available in Canada and the United Kingdom by prescription, made from MC. You spray it into your mouth.

There are two main cannabinoids, THC (also in a pill form, Marinol) and Cannabadiol (CBD). These have different effects when taken separately and when mixed with more or less of one or the other.

The concentration of THC has been rising in street marijuana. In 1980 the THC was 1.5%, 1997-4.5%, 2006-9.4%. This has been accomplished by breeders constantly looking for plants with more and more effect, probably getting high rather than treating symptoms.

The blood concentration of MC rises fast over 2 minutes when smoked and drops down to nearly zero in 20 minutes. Its effects seem to last for hours, so there must be some left in the tissues longer than its time in the blood.

There are two species of MC, Cannabis Sativa and Cannabis Indica. They have different effects. We did a study showing that the Indica was better for sleep, pain treatment, and less for getting high and giving energy. But this is based on opinions of MC users rather than tests on the plants or their blood. About 50% felt the label on the MC they received was incorrect—that’s scary.

MC is not regulated or standardized; you can’t go into multiple dispensaries and receive the same product. The breeding is not standardized and may be carried out by people who are intoxicated. So a patient must use trial and error to find the plant line that works for them and hope it doesn’t get changed for the worse in the future.

There are many animal studies showing good and bad effects on many medical conditions. But there is excellent evidence in humans for treating:
Spasticity, pain, and tremor of multiple sclerosis
Nausea, vomiting, weight loss, and appetite in cancer and AIDS
Chronic body pain (different from neuropathy)
Chronic neuropathy (nerve pain)

As far as bad effects the ones I am most concerned about are brains of those under 24 years old, since their brains haven’t fully formed and developed yet and pregnant females–smoking it chronically might affect the baby’s brains. There are conflicting reports of whether it causes cancer.

As an internal medicine specialist, I respect my national organization which says about a major report on MC by the Institute of Medicine:

“The IOM also concluded that compared with other licit and illicit drugs, including alcohol, tobacco, and cocaine, “dependence among marijuana users is relatively rare and dependence appears to be less severe than dependence on other drugs.”

No convincing evidence it is a “Gateway Drug”
“Given marijuana’s proven efficacy at treating certain symptoms and its relatively low toxicity, reclassification would reduce barriers to research and increase availability of cannabinoid drugs to patients who have failed to respond to other treatments.”

Daniel Pearce, D.O., FACOI, AAHIVS
Attending Internist, HIV Specialist, Arrowhead Regional Medical Center
Associate Professor of Internal Medicine, Assistant Director of Medical Affairs, Center for Advancement of Drug Research and Evaluation (CADRE) Western University of Health Sciences, College of Osteopathic Medicine of the Pacific
HIV Specialist Physician, AIDS Healthcare Foundation