I live in an area where medical and recreational marijuana (cannabis) is now legal. With all of the news, I have been wondering if the addition of recreational cannabis will stir more people to explore cannabis products for health reasons. I have also been wondering about the drug-drug interactions that may occur.
Since cannabis has not been legal for many, many years there is a lack of resource guides to ensure that drug-drug and drug-herbal interactions are safe. I am writing this as a cautionary reminder that all drugs, including caffeine, can have side effects and cause adverse reactions if combined with non-compatible substances. Please inform your healthcare providers if you use THC or CBD products as part of your personal health care plan. Additionally, if you take a prescription or over the counter drug, consult with your doctor, pharmacist, or other qualified provider about possible contraindications prior to exploring with cannabis products.
It is also important to know that the staff at the cannabis dispensary may not have the training necessary to know drug-drug interactions. According to a small study published in 2016 in Cannabis Cannabinoid Research, “Fifty-five percent of dispensary staff reported some formal training for their position, with 20% reporting medical/scientific training.” (DOI: 10.1089/can.2016.0024). This means almost half of the staff was not formally trained and most likely none were trained in drug-drug reactions. They might be well trained in knowing the best product for a particular health situation but all cases need to be considered as a whole.
Some good to know basics:
Cannabis can cause changes in blood pressure
Cannabis enhances CNS depressant effects when combined with alcohol, barbiturates and benzodiazepines (used for the treatment of anxiety, panic disorders, insomnia, PMS, and nervousness)
Warfarin levels (a blood thinner) may be increased by THC and CBD
Theophylline (a bronchodilator) levels may be decreased by smoked THC
Alcohol may increase THC levels
Clobazam (a sedative used in conjunction with epilepsy) levels in children may increase if combined with CBD
CBD may increase serum concentrations of macrolides, calcium channel blockers, benzodiazepines, cyclosporine, sildenafil (and other PDE5 inhibitors), antihistamines, haloperidol, antiretrovirals, and some statins (atorvastatin and simvastatin, but not pravastatin or rosuvastatin). And may increase antidepressant serum concentrations of SSRIs, tricyclic antidepressants, antipsychotics, beta blockers and opioids (including codeine and oxycodone).
Common adverse side effects to be aware of:
- Decreased sperm count
- Dry mouth
- Reduced coordination
- Altered sense of time
- Reddened eyes
- Reduced tear flow
- Ataxia – lack of voluntary coordination of muscle movements that includes gait abnormality
- Dysphoria – a state of unease or generalized dissatisfaction with life
I firmly believe that cannabis has a place in healthcare and that a lot of good will come from having THC and CBD products available to those in need. But until there is more literature out there, we all need to be cautious and ask advice from a reputable source.