Cannabinoids are the chemical components of Cannabis, which is a genus of plant from which marijuana is produced. A variety of cannabinoids exist, and some are psychologically active.Cannabinoids are used for a number of health conditions, including the alleviation of cancer pain and symptoms related to cancer treatments.
Two plant species, Cannabis sativa and Cannabis indica, produce a resin that contains cannabinoids. Some of the at least 85 cannabinoids present in Cannabis are psychoactive compounds, meaning that they affect the mental state, and can result in changes in cognition, behavior, perception, and mood. Cannabinoids, which are most highly concentrated in the plant flowers or buds, are often recommended to help cancer patients manage their symptoms and/or their response to treatment. They are also either used or under study to help patients with other health conditions.
Cannabinoids produce their effects by interacting with receptors located within the central nervous system. Two major types of receptors have been identified: cannabinoid receptor type 1, which is mainly located in the brain, and appears to be associated with the mood-altering euphoria that patients experience with the use of Cannabis; and cannabinoid receptor type 2, which is mainly located in the immune system, and appears to be associated with the therapeutic effects of Cannabis.
Overall, cannabinoids can have effects on memory, cognition, motor skills, and pain perception. They can also interact with reward centers that induce pleasurable effects.
Cannabinoids are classified into different major kinds, including, but not limited to:
1. Tetrahydrocannabinols (THC), one form of which—9 Tetrahydrocannabinol—is believed to be responsible for the characteristic psychoactive effects, or ‘‘high’’ of Cannabis. This includes such effects as euphoria, relaxed inhibitions, altered time and space perception, inability to concentrate, and intense relaxation.
2. Cannabidiols (CBD), one of the most common cannabinoids in Cannabis resin, may diminish the psychoactive effects of THC. In other words, the greater the concentration of CBD is, the less powerful are the effects of THC. CBD itself is not known to be psychoactive. The use of plants with increased CBD also has been shown to decrease anxiety among patients, and have other health benefits.
3. Cannabinol (CBN), a mildly psychoactive compound that is produced when THC comes into contact with air. CBN is similar to CBD in that it lessens the intensity of the effects of THC.
4. Cannabigerols (CBG), which is not known to be psychoactive.
5. Cannabichromenes (CBC), which is not known to be psychoactive.
Alternative-medicine practitioners, and in some cases medical doctors, recommend cannabinoids for use to treat a variety of health conditions. Their primary use has been to alleviate chronic pain when other methods have failed, or to counter nausea and vomiting associated with the use of chemotherapy drugs.
The U.S. Food and Drug Administration has approved cannabinoids for specific uses. These include:
1. Dronabinol, which is a synthetically produced compound used in the medicine MARINOL. It acts on the part of the brain that controls nausea, vomiting, and appetite. Dronabinol is used to help cancer patients cope with nausea and vomiting, a common side effect of chemotherapy; and to treat the loss of appetite and weight declines typical of individuals who have acquired immunodeficiency syndrome (AIDS).
2. Nabilone, which is a synthetic cannabinoid contained in the medicine Cesamet. Nabilone has a chemical structure similar to that of THC. Like dronabinol, it also alleviates nausea and vomiting associated with chemotherapy.
Other potential medical uses:
Cannabis could substitute for some or all of the opioids used by patients in a palliative care setting who were experiencing chronic pain. The study demonstrated that either Cannabis alone or Cannabis in combination with a lower dose of opioids than that typically prescribed for patients provided relief. The researchers also noted that while opioid use can result in death, no lethal dosage of Cannabis exists.
Cannabinoids have also been shown to have some benefit for cancer patients by fighting inflammation, inhibiting cell growth, and hindering tumor growth by blocking the growth of blood vessels necessary for tumors. Studies have shown that cannabinoids may protect against intestinal inflammation and therefore reduce the risk of colon cancer; that they damage or kill liver cancer cells; and that they selectively kill breast cancer cells while leaving normal breast cells unharmed.
To relieve chronic pain, we recommend that you use:
Patients take cannabinoids in a variety of ways. Some patients smoke marijuana to inhale the cannabinoids, or ingest marijuana baked into brownies or brewed as an herbal tea. Plants vary in their concentrations of cannabinoids, however, so the dosages patients receive through these methods also vary.
Newer preparations of cannabinoids, however, are more refined and permit more regulated dosages, and often either eliminate THC or modify the psychoactive side effects of THC that are acquired through smoked or ingested marijuana. Cannabinoid preparations may come in capsules, which are taken by mouth, or as mists, which are typically sprayed under the tongue. Dronabinol and nabilone, for instance, come in capsule-form preparations. Sativex is being tested as a spray.
To treat nausea and vomiting associated with chemotherapy, dronabinol-containing capsules are typically taken by mouth in four to six doses per day: one dose 1 to 3 hours before chemotherapy and additional doses every 2 to 4 hours afterward. To increase appetite, it is usually taken either once or twice daily.
Dosages may vary based on the concentration of dronabinol in each capsule. Capsules typically contain 2.5, 5, or 10 mg of dronabinol.
Nabilone-containing capsules are usually taken two to three times a day during chemotherapy to alleviate nausea and vomiting. Treatment typically begins 1 to 3 hours before the first dose of chemotherapy and continues for up to 48 hours thereafter.
Because plant concentrations of THC and other cannabinoids vary widely, it is difficult to accurately determine a patient’s dosage through the smoking of a marijuana cigarette or through the ingestion of a marijuana brownie, marijuana-containing herbal tea, or other means.
Side effects vary. They may include one or more of the following, or others: dizziness, sometimes including unsteadiness; headache; drowsiness; insomnia; nausea; anxiety; changes in appetite; confusion; weakness; dry mouth; altered mood (feelings of euphoria), judgment, or memory; seizures/convulsions; inability to concentrate; depression; rapid heartbeat; hallucinations; lightheadedness or fainting; paranoia; and inability to think clearly.
Compared to opiates and benzodiazepines (such as valium), cannabinoids are considered either far less addictive, or non-addictive. Some patients do, however, experience withdrawal symptoms when they stop using cannabinoids. These may include insomnia, restlessness, irritability, and hot flashes. Symptoms usually fade and disappear within a few days.
Patients with a personal medical history or family medical history of addiction to drugs or alcohol, or any other addictions should notify their health practitioners before using cannabinoids, as these might make them more susceptible to possible addiction. Patients should also notify their health practitioners about any allergies they have, particularly but not limited to cannabinoids. Drug preparations may contain additional substances beyond cannabinoids, and patients may be