MJ Interacts with 65 Medications
Researchers from Penn State College of Medicine in the United States have conducted a study on the pharmacological properties of MJ (marijuana). The scientists discovered that the plant interacts with at least 65 different medications.
How Cannabis Enhances the Effects of Certain Drugs
Cannabinoids are metabolized in the liver by enzymes such as cytochrome P450 (CYP3A4, CYP2C9, and CYP2C19) and UDP-glucuronosyltransferase (UGT1A9 and UGT2B7). These enzymes also play a role in the metabolism of many medications in the liver. As a result, THC and CBD can slow down the chemical reactions that break down substances in these drugs. This process can enhance the effects of medications, which is why doctors do not recommend using MJ with any drugs that are broken down by these enzymes.
The list of prescription medications that interact with cannabis through these enzymes includes 57 names.
MJ Increases Drug Potency
THC and CBD have a high degree of protein binding, which means that taking cannabinoids can increase the amount of a drug that is in its free (active) form. An increase in the unbound portion of a medication leads to greater activity and a higher risk of side effects. Researchers found that MJ has a significant impact on the potency of drugs with high protein binding (over 85%) and a low therapeutic index (indicating a high risk of toxic effects). These medications include:
- Amphotericin B
- Cyclosporine
- Levothyroxine sodium
- Phenytoin
- Quinidine
- Tacrolimus
- Valproic acid
- Warfarin
To assess the consequences of taking cannabinoids and a medication at the same time, it is important to consider the drug’s mechanism of action. For example, warfarin reduces blood clotting, so using it together with MJ can increase the risk of bleeding.
What Factors Influence MJ’s Interaction with Medications?
The degree to which cannabis affects a medication depends on dosage, method and frequency of use, gastrointestinal absorption, liver function, kidney excretion, and genetic profile. The more frequently and heavily a person uses MJ, the more significant the clinical impact cannabinoids will have on the drug. In most cases, MJ intensifies the side effects of medications. For example, taking cannabinoids together with sedatives (muscle relaxants, barbiturates, and benzodiazepines) can increase nausea and drowsiness. Smoking MJ can also intensify negative cardiovascular reactions to drugs that cause hypotension, hypertension, or tachycardia.