That medical cannabis should be studied more extensively and should undergo more clinical trials is already an established fact.
While there are scientific pieces of evidence proving the effectiveness of cannabis in the treatment of certain medical conditions, more research has to be done to set all these in stone. Everything else is anecdotal evidence.
Setting expectations for first-time medical cannabis users
When deciding to use medical cannabis, a patient should understand:
- That cannabis is not a cure-all solution, even if it’s been touted as the miracle drug.
- That what has worked for one patient with a certain type of illness may not exactly work for another patient with the same medical condition.
- That individuals respond differently to marijuana.
Patients should always keep in mind that there are also risks involved in taking medical cannabis. Even if most people who advocate for cannabis and who have used it themselves claim and attest that the drug is safe and free of side-effects, your body may not entirely agree. You should also know that there could be precautions and contraindications that may have not yet been previously explored.
When taking medical cannabis for the first time, the key is to listen to your body and the way it reacts. If you are expecting relief from a particular symptom — based on what you have heard or read about — but instead you feel discomfort or you feel differently from the promised effect, exercise better judgment.
We know medical marijuana presents a lot of hope for those who are desperate for healing or for the alleviation of pain and other symptoms, and you’d want to give it all the chances to deliver the results you are told to expect. But if what it gives you is something else instead, move on to the next treatment option available.
Sure, medical cannabis comes in different doses, different product types, and different strains, and you can ask your doctor or medical professional about trying out a different one from what you have been given. However, you should be able to tell if cannabis — regardless of dose, product type, or strain — is really not for you.
What’s more, if you are suffering from a serious medical condition and are taking various pharmaceutical medications, you may want to check out whether cannabis can be taken in tandem with these other drugs. Because cannabis can have interactions with these.
Cannabis consists of hundreds of active compounds, including over a hundred cannabinoids. And because of this, there are a lot of possible drug interactions.
In fact, Drugs.com has listed 484 moderate interactions and 129 major interactions that cannabis can have with other medications like Benadryl, cetirizine, diazepam, ketamine, lorazepam, morphine, Xanax, Zoloft, codeine, fentanyl, acetaminophen, pregabalin, oxycodone, and hydrocodone.
Here are some examples of the specific interactions between cannabis and certain drugs:
Fluoxetine and cannabis have a moderate interaction rating, so patients should be cautious about combining these two drugs.
Taking cannabis with fluoxetine may cause hypomania, wherein the user feels irritated, excited, nervous, and jittery.
Antipyrine is an analgesic and antipyretic that is administered orally or as ear drops to relieve ear pain and ear infection. It is also often used in testing the effects of other drugs on drug-metabolizing enzymes in the liver.
Patients who take antipyrine are advised to be cautious about combining this medication with cannabis and to talk with their healthcare provider first.
The body breaks down antipyrine in order to get rid of it. However, some chemicals in cannabis might decrease how quickly the body breaks antipyrine, and this might increase the antipyrine levels in the body, resulting to an increase in its effects and side effects.
Disulfiram has a moderate interaction rating, and patients must be cautious about combining this drug with cannabis. Cannabis with disulfiram may cause hypomania, making the user feel irritable, jittery, nervous, and excited.
Medications changed by the liver
Some medications — such as acetaminophen,ethanol, chlorzoxazone (Parafon Forte), theophylline, lovastatin (Mevacor), cyclosporine (Neoral, Sandimmune), clarithromycin (Biaxin), estrogens, indinavir (Crixivan), diltiazem (Cardizem), triazolam (Halcion), and anesthetics such as halothane (Fluothane), enflurane (Ethrane), methoxyflurane (Penthrane), and isoflurane (Forane) — are broken down or changed by the liver. Cannabis might quicken the time the liver takes to break down some meds, and this might decrease the effects or side effects of some of these medications.
Medications moved by pumps in cells
Some drugs are moved by pumps into cells. Cannabis might make these pumps less active and therefore increase how much some of these meds get absorbed by the body. This might increase the side effects of some of these meds.
These meds that are moved by these pumps include ketoconazole, erythromycin, loperamide (Imodium), itraconazole, amprenavir, vinblastine, vincristine, vindesine, etoposide, nelfinavir, saquinavir, paclitaxel, indinavir, diltiazem, verapamil, corticosteroids, cisapride (Propulsid), cimetidine, ranitidine, fexofenadine (Allegra), cyclosporine, and quinidine, among others.
Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Cannabis might slow blood clotting, and taking cannabis extracts along with medications that also slow down clotting might increase the likelihood of bleeding and bruising.
These medications that slow down clotting include aspirin, ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), diclofenac (Voltaren, Cataflam, others), clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, and warfarin (Coumadin).
Sedative medications (Barbiturates, CNS depressants)
Cannabis can cause one to be sleepy and drowsy. Taking cannabis along with sedative meds like lorazepam (Ativan), phenobarbital (Donnatal), and zolpidem (Ambien) might cause too much sleepiness.
Special precautions, warnings, and contraindications
Cannabis has been found to reduce thyroid stimulating hormone levels. So, for those who have thyroid problems, taking cannabis means artificially suppressed TSH. And this can affect medication decisions.
A review in Current Opinion in Neurology has found that the use of cannabis worsens ringing of the ears or tinnitus, which is a common problem for Meniere’s disease and Charcot-Marie-Tooth disease patients, as well as for the elderly.
Moreover, a 2014 study has found that cannabis use reduces platelet aggregation and is therefore risky and problematic for those who have low platelet counts and bleeding disorders.
Also, based on contraindications for existing synthetic cannabis medications — i.e. dronabinol and nabilone — Health Canada suggested that the risk/benefit ratio of marijuana needs to be considered for those who:
- are below 18 years old
- have a history of hypersensitivity to cannabis smoke or to any cannabinoid
- have respiratory disease like chronic obstructive pulmonary disease (COPD) or asthma
- have severe cardio-pulmonary disease with occasional low blood pressure (hypotension), possible high blood pressure (hypertension), loss of consciousness (syncope), or rapid heart rate (tachycardia).
- have a history of substance abuse
- have a family history of schizophrenia or a personal history of psychiatric disorders
- have severe renal or liver disease, including hepatitis C
- are women of childbearing age who are trying to conceive, are pregnant, not on a reliable contraceptive, or are breastfeeding.
Additionally, Health Canada suggested that medical cannabis be used with caution by those who are taking sedatives or other psychoactive drugs or have mood disorders.
Meanwhile, in 2014, the College of Family Physicians of Canada came up with its first guideline for physicians that focused on cannabis for the treatment of anxiety or chronic pain. The CFPC guideline not only listed the inappropriate candidates for medical cannabis treatment, but it also rated the level of research evidence for the CPFC’s recommendations.
The CFPC’s rating scheme consisted of 3 levels:
Level I: strongest evidence, with well-conducted controlled trials or meta-analyses
Level II: strong evidence, with well-conducted observational studies
Level III: weakest evidence, with the consensus of the expert members of the committee writing the guidelines
In their document, the CFPC advised physicians to not authorize the use of medical cannabis to these patients:
- Patients who are under 25 years old (Level II)
- Patients who have a strong family history or personal history of psychosis (Level II)
- Patients who are pregnant, are planning to get pregnant, or are breastfeeding (Level II)
- Patients who have a past or current cannabis use disorder or any other active substance use disorder (Level III)
- Patients who are suffering from respiratory or cardiovascular disease (Level III)
The CFPC also advised that caution be used in recommending medical cannabis for patients who:
- smoke tobacco (Level II)
- have an anxiety or mood disorder (Level II)
- are heavy alcohol users or take high doses of a class of tranquilizers called benzodiazepines, opioids, or over-the-counter or prescription sedatives (Level III)
- have risk factors for cardiovascular disease like stroke (Level III)
Because of the gaps in medical cannabis research, none of the CFPC’s recommendations are under Level I, or are backed by the “gold standard” of evidence, randomized controlled trials, or meta-analyses, which is a kind of systematic review combining and analyzing data from RCTs.
Instead, most of these recommendations are Levels II and III, or were based on observational studies or expert opinion.
The CFPC guidelines may be a start, but anxiety and pain are the only two potential indications for medical pot. Additionally, some of the possible contraindications that are listed by Health Canada are not addressed by the CFPC, and this could be a point of confusion.
Rxlist.com has explained why cannabis use is possibly unsafe for certain individuals and situations:
Pregnant women. Marijuana is potentially harmful when smoked or taken orally during pregnancy. This is because the drug passes through the placenta and may slow down fetal growth. Cannabis is also associated with abnormalities in the fetus and childhood leukemia.
Breastfeeding mothers. The same goes for the use of cannabis among mothers while breastfeeding. The psychoactive component of the drug — tetrahydrocannabinol — passes into the breastmilk and the extensive use of the drug during breastfeeding may result in the baby’s slow development.
Patients with heart disease. Cannabis may cause rapid heartbeat and short-term high blood pressure, and it may also increase a patient’s risk of having a heart attack.
People with compromised immune system. The cannabinoids in cannabis can weaken the immune system and can make it more difficult for the body to fight infections.
People with bipolar disorder. The use of cannabis might worsen a bipolar patient’s manic symptoms.
People with depression. Frequent cannabis use might worsen the symptoms of depression.
Lung disease patients. The long-term use of cannabis may worsen lung problems. Regular and long-term cannabis smoking has also been associated with lung cancer and several cases of an unusual type of emphysema.
Multiple sclerosis patients. Oral consumption of cannabis might worsen the symptoms of multiple sclerosis.
Patients who have previously suffered a stroke. The use of cannabis after a stroke might increase the patient’s risk of having a second stroke.
People who are scheduled for surgery. Cannabis affects the central nervous system, and using it might slow the CNS too much when it is combined with anesthesia during surgery and any post-op medications. It is advised that patients stop using the drug at least a couple of weeks before a scheduled surgical operation.
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There is a need for more guidelines in order to address all patient populations that may be eligible for medical cannabis treatment, like those suffering from cancer, multiple sclerosis, and HIV/AIDs. These guidelines may help with ethical and medical issues that may arise. For instance, should we apply the contraindications in the CFPC report to palliative-care patients, or to people with serious conditions who have not benefited from conventional therapies?
For now, what’s certain is this: There a lot of questions that remain pertaining to the appropriate use of medical cannabis.