Cannabis vs Pharmaceutical Drugs


Pills vs Pot

"Well-known brands of hay fever tablets, painkillers and sleeping pills pose a previously unknown threat to people’s health when taken together, British scientists claim." - The Telegraph

The quick and dirty answer is YES.  Marijuana can definitely interact - positively or negatively - with your medication.   


Until recently, Cannabis has been out of the loop, a non-option, for prescription by medical doctors.  In depth knowledge about Cannabis based medicines interaction with prescription drugs is limited due to the herb's unfortunate stint (80 years) as an illegal drug.  As such, most orthodox doctors have little experience or training in cannabis based medicines.  However, many medical practitioners are equipped with the acumen and experience that will allow them to safely incorporate marijuana into their treatment regimes / repertoires.  Cannabis based medicines are generally far less toxic than many pharmaceuticals and have fewer side effects, a fact that makes multiple-drug management including MMJ an easier task.

"The drugs, including common allergy treatments Piriton and Zantac, as well as Seroxat, an antidepressant, are thought to be used by half of the 10  million over-65s in Britain. Many of the drugs, when taken in combination, were found to more than treble an elderly patient’s chance of dying within two years." - The Telegraph

What's happening to folks and our elderly in particular, is downright scary.  Gauging the exact effect of but one drug on an individual is a difficult task, let alone predict the interaction of a half a dozen medications taken simultaneously.  Here is what a prominent medical doctor has to say.  

"The average person over 65 now uses seven different medications per day, four prescribed and three over-the-counter, There's never been a controlled study on a human being involving more than three drugs circulating in the body at the same time. So no one knows, scientifically, exactly what's going on in your body when you take seven, 10, or a dozen at a time." - Andrew Duxbury, MD, associate professor of geriatrics at the University of Alabama.



Here is a second opinion from a popular medical website.

“Drug interactions are the Achilles heel of the medical profession. The laws of nature no longer hold true. This is a crazy world where one plus one equals three, where down may very well be up and surely pigs have wings. In fact, mixing medicines is very much like playing Russian roulette. You never know when a particular combination will produce a lethal outcome.” - Joe Graedon

There are way too many cases of death caused by lethal drug interactions.  Prince, Michael Jackson, Glenn Frey and perhaps soon Hillary Clinton are among the casualties.  Which goes to show that even if you have fame and fortune, your exotic cocktail of drugs can easily be fatal.  In the case of Prince, authorities think a combination of Percocet and Buprenorphine could well have ended the singer’s life prematurely. It is known that Percocet and Buprenorphine suppress breathing, and using the two in combination creates a “dangerous synergistic effect.”



Can Marijuana cause dangerous interactions with my medication too?  What kind of interactions should my doctor look for?  Can Medical Marijuana replace or lower the dose of some of my existing medication?

To understand medical marijuana's potential interactions with pharmaceutical drugs, one first has to understand what is in the medicine.  Each variety or strain of marijuana contains a unique assortment of several hundred compounds, many of which are medicinal.  The most important and abundant medicinal ingredients in  Marijuana are compounds called cannabinoids.

Medical grade marijuana should come with a certificate of analysis (cannabinoid profile) that quantifies the main active ingredients THC and CBD as well as several other cannabinoids. The ratios between CBD (non psychoactive) and THC (psychoactive) dictate largely the pharmacological effects.  In addition, Cannabis also contains many terpenes (aromatic compounds), that also have therapeutic effects.    

The discoverer of THC, Dr. Raphael Mechoulam found out early on that various cannabinoids present in marijuana work in synergy and are more effective / palatable medically when taken together as nature provides.  Of course, the pharmaceutical industry want's to isolate and synthesize individual components of marijuana and then study the effects in clinical trials.  So there is a failure by orthodox medicine to recognize the essential nature of biological systems.  Biological systems are complex and nothing works in isolation.  Calculating the effects of a drug using simple models in this arena of complexity is simply a gross oversimplification of the process.  

Of course, the question about drug administration and interactions is best answered by medical practitioners with deep experience in recommending medical marijuana.  

"Entourage effect is a phrase that was introduced in cannabinoid science in 1998 by S. Ben-Shabat, with Raphael Mechoulam, to represent a novel endogenous cannabinoid molecular regulation route. Biological activity assayed together with inactive compounds. References whole-plant and whole-person caregiver synergy treatments over isolated compound pharmacological dosage."- Wiki

Dr. Paul Hornby, a PhD. in pathology and medical marijuana guru of sorts has found that THC and CBD interact to produce a balancing effect mentally, whereas THC alone can cause temporary psychosis. Fold musician, Neil Young recently shared his findings that chewing on a few black peppercorns (full of terpenes) stops feelings of paranoia that can happen even with experienced users.

Interactions of cannabis with other drugs in man.

In this PUBMED report (the world's largest medical document source), it was found that only THC interacted measurable with booze (ethanol) and barbiturates.  Effects were additive, in the positive and negative directions.  CBD did not register a notable co- effect with any drug in the study. However, it was speculated that CBD might well moderate or block the action of psychoactive THC, thereby reducing impairment while medicating.  In addition, there was a wide variety of responses between individuals and this finding is very significant when predicting impairing effects and pharmaceutical benefits.

Differential effects of cannabis extracts and pure plant cannabinoids

This study found that THC and especially CBD elevates intracellular levels of Calcium.  This effect will may be additive and should be an important consideration when taking medication that affects cellular calcium levels.  The study concludes that THC and CBD interact synergistically as well.

Cannabinoid-induced alterations in brain disposition of drugs of abuse

Pretreatment with CBD enhanced the brain levels of subsequent uptake of both THC and Cocaine while co-effects were negligible with morphine, methadone, o\r methamphetamine. These results imply that CBD may be useful to enhance the uptake of certain drugs while lowering the dose and side effects.

GW Pharmaceuticals Research on Cannabinoid Medical Applications

GW Pharmaceuticals is a leader (market cap is $2 billion) in the medical application and research of cannabis based medicines.  Studies by GW Pharmaceuticals imply that cannabidiol is often better tolerated, is lower in toxicity and has less generally less problematic drug interaction issues.  GW investigated the use of a sublingual spray containing THC:CBD for pain in spinal cord injury, pain and sleep in MS, spinal cord injury, neuropathic pain in MS and general neuropathic pain. Results from trials showed that THC:CBD caused a statistically significant reduction in neuropathic pain in patients with MS and other conditions. In addition, improvements in other MS symptoms were observed. Phase II studies of THC:CBD were completed in patients with MS, spinal cord injury, neuropathic pain and a small number of patients with peripheral neuropathy secondary to diabetes mellitus or AIDS.


Annual Deaths by Marijuana - Zero


While this chart might be indicative of the overall situation, there is a significant problem with people freaking out on high THC weed and being admitted to emergency.  The good news is that the effects of paranoia wear off after a several hours.



Mayo's findings are summarized in bullet point, click on the Mayo Clinic link (title) for details.

Marijuana may increase the risk of bleeding when taken with drugs that increase the risk of bleeding.  

  • Doctor's might consider if blood thinning medication can be reduced if marijuana is indicated.

Marijuana may affect blood sugar levels. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional.

  • Doctor's can observe cause and effect, and regulate insulin and cannabis medication accordingly.

Marijuana may cause low blood pressure. Caution is advised in people taking drugs that lower blood pressure.

  • Physicians can consider using Cannabis  based medicines to work with other blood pressure lowering medications.

Marijuana may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system. As a result, the levels of these drugs may be increased in the blood and may cause increased effects or potentially serious adverse reactions.

  • Again, the positives and negatives of this potential inter-drug reaction should be studied.

Marijuana may increase the amount of drowsiness caused by some drugs.

  • Since marijuana comes in so many types, psychoactive, non-psychoactive and many other varieties, the cause and effect should be monitored carefully, particularly when THC is high in the cannabis based medicine.

Marijuana may also interact with agents that; affect blood vessel width, the immune system, be toxic to the liver, improve breathing or treat lung disorders, increase appetite, treat heart disorders, treat nausea or vomiting, treat nervous system disorders, agents that may treat psychiatric disorders, agents that may treat retrovirus infections (HIV), treat skin disorders, treat stomach disorders.  

  • these interactions may mean that marijuana might be used as the lead therapy and other drug doses might be reduced or eliminated entirely.

Cannabis based medicines can interact with anabolic steroids, anticancer agents, antipyrine, antiseizure agents, bromo-dragonFLY, cannabinoid CB1 receptor antagonists, central nervous system depressants, cocaine, corticosteroids, dopamine antagonists, ecstasy, estrogens, fertility agents, hormonal agents, nicotine, nonsteroidal anti-inflammatory agents, opioid receptor antagonists, pain relievers, p-glycoprotein-regulated agents, prochlorperazine, sedatives, and synthetic cannabinoids.

  • complementary and detrimental relationships need to be considered carefully.  

Medscape on Marijuana

  • Cannabis is Analgesia, Antiemetic, Appetite Stimulant, Glaucoma.

  • Dosing of marijuana preparations is highly dependent on a variety of factors (eg, growing and harvesting conditions, plant parts isolated).

  • No standard guidelines exist for dosage ranges.

Web MD

WebMD chimes in with the opinion that marijuana based drugs are not advised as pain killers because it makes the user sleepy.   What can you say about that kind of statement?  Not all Cannabis based meds make you sleepy and for a chronic pain sufferer, a side effect that includes a good night's sleep is a blessing.  And, of course many over the counter and prescribed drug warnings include drowsiness.

Pharmacy Times - Drug Interactions with Marijuana

This group knows about marijuana based medicines and provides clinical evidence about potential drug interactions.

Drug interactions A Family Guide to Concurrent Disorders - Part III: Treatment

Caffeine, alcohol, nicotine and marijuana interaction with pharmaceutical drugs is discussed. This group warns that marijuana is addictive, which flies in the face of most current research and statistical evidence.  While marijuana might cause an addiction for some, like Jim Carrey, who feels like he's on holiday too much, most studies find that cannabis has the lowest addiction rate of any of the major drugs, legal and illegal.


The Dangers of Different Drugs - A Comparison

Chart source Drug Wars:


The effect of prescription drugs can be compounded – or weakened – when combined with Cannabis.  Cannabis was often prescribed with opium before 1930 for pain.  Recently, some physicians report that patients using cannabis with non-steroidal anti-inflammatories have better relief of pain. this is great news, but the additive good effects could be too much of a good thing.  Over relaxation and drowsiness of these two drugs in combination could be fatal. It should be noted that Cannabis use alone has seldom, if ever caused death alone.  The strategy of some physicians is to try dosing with moderate amounts of Cannabis medicines with different ratios of CBD and THC and then consider adding other drugs as required.


Suppressants and Sleeping aids

When cannabinoids are mixed with other suppressants, sleeping aids and such, the effect can often be additive.  If a patient is using drugs like Sonata, Lunesta, Ambien; and Zimovane and the practicing physician is interested in prescribing cannabinoids, then the dose of the pharmaceuticals may well need to be reduced or eliminated entirely.



Cannabis can make anti-antihistamines more potentiated and drowsiness may result, so lowering the dose might be required.  Cannabis can can amplify some of the effects of alcohol, which is true of many other medicines.

Blood sugar lowering meds

Diabetics take warning, blood sugar lowering Metformin and Glucophage, interacts with Cannabis.   Some types of cannabis were shown to interfere with the effectiveness of Metformin.  



Hypertension is often treated with antihypertensives to lower blood pressure.  Some types of marijuana can either lower or raise (speed weed)  blood pressure, depending on the strain and the individual.  Therefore, patients should monitor the effects of their medications to see that their medication is effective.


Tricyclic antidepressants and SNRIs

Both cannabis based medicines and tricyclic antidepressants or other drugs (SNRIs) that inhibit the uptake of serotonin and norepinephrine are used in anxiety disorders, obsessive-compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), chronic neuropathic pain, fibromyalgia syndrome (FMS), and PMS.  Drugs include amitriptyline, amoxapine and desipramine. When combined with Cannabis there is a potential of interaction, an increase in drowsiness and sedation.


Tachycardia and hypertension may occur when marijuana is combined with stimulants.

Medications for hypertension or arrhythmias, or patients with cardiovascular issues should be cautious to monitor their response to a new strain of Cannabis. This caution applies when mixing other stimulants - such as amphetamines, cocaine and coffee - with marijuana.


Antipsychotic Medications

Marijuana might interfere with drugs used to treat depression and bipolar symptoms. Currently, there is a lot of interest in how CBD and CBD:THC balanced strains work to help treat psychosis and depression.


Cannabis has been shown to increase the metabolism of Theophyllines; which is used to treat asthma and chronic obstructive pulmonary disease.  Cannabis might be useful to lower the dose of theophyllines required.



How to Safely Combine Medical Marijuana with Pharmaceuticals

A Deadly Drug Interaction Often Ignored by Doctors and Pharmacists

Entourage effect of Cannabinoids

Drugs that May Interact with CBD Oil


420EVALUATIONSONLINE specializes in online medical doctor's recommendations.

Patients that are concerned about Marijuana and potential drug interactions should consult a medical doctor or healthcare professional with deep experience cannabis based medicine.  Access to lab tested marijuana, complete with an accurate cannabinoid profile is very important to identify the medicine that is best for a given condition or symptom.  To purchase lab tested marijuana in the State of California, patients need a recommendation from a licensed physician.

The process is completed entirely online in minutes using our user friendly application system. Our services comply with the California Board of Medicine's guidelines for Telehealth services.

420EVALUATIONSONLINE also also supplies:

  • Cannabis ID Cards

  • Grower's Permits

  • Renewals (from anywhere)

  • Online verification of patient's legal status


Blog, Health & News, Research reports and other documentation at is intended for informational purposes only.   We do not diagnose, treat or cure disease.  Readers with questions that arise from reading any information on this site should consult a licensed physician or a trusted health professional before taking any medical action.  Our medical activities are limited to Medical Marijuana Evaluations and Recommendations within the State of California.  

Pills and Pot

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