Drug Interactions: Using Cannabis With Pharmaceuticals

Short Story:  When whole-plant cannabis is used solo without any pharmaceuticals, the potential side effects are very limited and the only variable to worry about is taking too much.  However, when used in conjunction with other pharmaceuticals, drug interactions need to be considered just as combining any 2 or more anti epileptic drugs (AEDs).


Long Story:  The p450 cytochrome system helps the body process chemicals, both natural and synthetic.  The majority of AED’s, and most drugs,  rely on this system to metabolize the drug into a useful form.  A large portion of this system is in the liver, which is where drugs are sent after digestion.  Drugs are affected by  liver enzymes (cytochromes) and using more than one drug can affect they way the cytochromes interact with the drugs.  This in turn affects how they enter the bloodstream and the rest of the body.


If 2 drugs using the same enzymatic action are in the liver at the same time, it can produce negative affects, most noticed by an epileptic.  Of course many drugs have contra-indications.  This is why there is a list of food and drugs to watch out for in many prescriptions.  One drug can act on the cytochromes to induce (exacerbate) or inhibit (stop) the expected actions of another drug.  This can be dangerous in treating seizures especially when very small changes in a pharmaceutical can lead to very big changes in seizure activity.


Although there are several charts with guidelines for interactions, they are based on the assumption that these drugs only interact with ONE cytochrome.  This is not reality.  All drugs are in some way impacted by all cytochromes and everyone’s metabolic system is different.  So I will attach some charts but know your child may have different reactions.  We found a reaction with Keppra and CBD that was not expected, but then again no one knows exactly how Keppra works in the body.  It is expected to not be metabolized significantly by the p450 system but there it still goes there


http://www.medsafe.govt.nz/profs/Datasheet/k/Keppratab.pdf


If you have the opportunity to try cannabis BEFORE all of the pharmaceuticals I consider you in a very fortuitous position.


Longer Stories:


https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1312247/table/TU1/

https://www.medscape.com/viewarticle/884459

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001218/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1312247/