Does Cannabis Have Negative Interactions with Your Pharmaceuticals?

Cannabis can have a negative interaction with your pharmaceuticals, although it presents much less threat than other stimulants.

Cannabis indica and Cannabis sativa are the most prominent cannabis species. Analytical chemists study the species’ respective profiles as more important than their respective strains.

As a poly-pharmaceutical herb, cannabis has 108 cannabinoids, including the prominent THC and CBD. Terpenes are aromatic compounds, and at least 420 constituents make up the chemistry.

The Department of Health finds two critical concerns:

1. “Serious adverse effects are rare with cannabis or its constituents.
2. “Marijuana has low to moderate dependence potential; the active dose is very far below the lethal dose.”

So, it’s worth considering if and how cannabis produces negative interactions with your pharmaceuticals.

Five first thoughts

Cannabis is absolutely contraindicated for people who have acute psychosis or severely unstable psychiatric problems. It is prohibited for those already suffering severe cardiovascular, liver, or kidney disease. And cannabis use may aggravate existing arrhythmias.

There are too many combinations of medications and permutations of chemicals involved to cover here. But, we do want to cover some well-known issues.

1. Alcohol: Combined with alcohol, cannabis will increase dizziness, drowsiness, and poor motor control.
2. Anticoagulants: Anti-platelet drugs thin the blood to reduce clotting. Cannabis may increase the risk of bleeding. Anticoagulants include name brands like Coumadin, Xarelto, Pradaxa, Eliquis, etc.
3. Antidepressants: Cannabis may enhance the sedative effects of popular antidepressants, including Zoloft, Prozac, Celexa, Lexapro, and more.
4. Protease inhibitors: Cannabis can reduce the effectiveness of antiviral pharmaceuticals like Agenerase, Reyataz, Prezista, and still more.
5. SSRIs: Adding cannabis to Selective Serotonin Reuptake Inhibitors, such as Celexa, Lexapro, and Paxil, may increase the risk of mania.

Negative interactions with your pharmaceuticals

Pharmacy Times puts the interactions between cannabis and pharmaceuticals more specifically.

♦  THC is metabolized by CYP269 and CYP3A4.3. CYP2C9 breaks down (metabolizes) compounds, including steroid hormones and fatty acids. CYP3A4 oxidizes small foreign organic molecules, such as toxins or drugs so that they can be removed from the body.

No studies have been done on how CYP269 inhibitors eliminate THC. However, science says it would be expected that CYP269 inhibitors—amiodarone, cimetidine, cotrimoxazole, metronidazole, fluoxetine, fluvoxamine, fluconazole, and voriconazole—would inhibit THD elimination.

CYP3A4 inhibitors, including ketoconazole, clarithromycin, erythromycin, cyclosporine, verapamil, itraconazole, voriconazole, and boceprevir, would be expected to produce an increase in the concentration of THC by 1.20 and 1.8- fold.

♦  CBD plasma concentration increased 2-fold in combination with ketoconazole. Rifampin reduces CBD content by 50% to 50%. “Other CYP3A4 inhibitors and inducers should be expected to have a similar effect on CBD plasma concentrations if co-administered.”

What does this mean to you as a cannabis user?

You would need to know all the ingredients in your prescription pharmaceutical, the proportion of their presence, their respective mechanism of action, and more to make prudent decisions.

♦  A study of Self Reports of the Interaction between Substance Abuse and Schizophrenia published in the Australian & New Zealand Journal of Psychiatry found that “Only cannabis increased positive symptoms of schizophrenia, and only amphetamines reduced negative ones.”

♦  The Pharmaceutical Journal reports, “Cannabinoids are highly protein bound (up to 97 percent) and release of both THC and CBD from fatty tissue is slow, sometimes taking up to a month in heavy users.” This metabolism creates some potential for pharmacokinetic interactions.

We don’t know for sure more than this because there is so little valid research in long-term focused human studies. Even permitting research, finding a place to start would be hard. You would have to study each dose of each strain in combination with each pharmaceutical in diverse circumstances.

But some things seem clear given what we know now.

Does cannabis have harmful interactions with your pharmaceuticals?

You must surrender readily to common sense once you set aside the clear counterindications covered above.

Any fool can see that cannabis used in combination with alcohol, meth, heroin, cocaine, hallucinogenics, and other inebriants and stimulants will exacerbate the effects of the cannabis in body and mind experiences. Forget the warnings about operating heavy equipment. You’re making a mistake!

Otherwise, the research does not support any concerns you cannot manage. The sedative effects attributed to CBD will increase the sedation in antidepressants, anti-inflammatories, and SSRIs.

THC will increase blood pressure and heartbeat. When used in combination with blood pressure medications, blood thinners, and beta blockers, the THC potency will risk bleeding and blood makeup.

Users must exercise prudence in selecting strain, dosing, and frequency. If you have a known and severe medical condition, you should be cautious about cannabis use in general. If you are treating with pharmaceuticals, you should research the potential for counterindications. And, if you have any doubt, you must confer with your prescribing doctor or medical cannabis doctor.

The pharmaceuticals mentioned here are among the most valued and successful pharmaceuticals. Many have not been marketed long enough to be subject to long-term study. Few pharmaceutical leaders are promoting research on the interaction of cannabis and pharmaceuticals.

So long as you stay heads up, it’s left to your common sense and some trial and error to get it right!