Ask Dr. Leigh: how do I start a medical cannabis regimen?

talking to doctor about medical cannabis

Using cannabis can have a big impact on your physical and mental health—for better, and once in a while, for worse. That’s why it’s important to consult a healthcare provider before experimenting.

Here at GreenState, cannabis clinician Dr. Leigh Vinocur is here to answer your questions on healthy living with cannabis.

Editor’s Note: The answer to this question is meant to supplement, not replace, advice, diagnoses, and treatment from a healthcare provider.  Always consult a medical professional when using cannabis for medicinal purposes, and do not disregard the advice of your healthcare provider because of anything you may read in this article. 

RELATED: Ask Dr. Leigh: What is the entourage effect?

Q) How do I begin using cannabis for my medical condition? 

This is a good question, but I want to preface this and say by answering this question, I do not recommend that you use this information on your own to start using cannabis as a medical treatment without talking to your physician or a medical cannabis clinician. 

And by clinician, I mean someone allowed in your state to certify and counsel you on the therapeutic use of medical cannabis. That can be a physician, nurse practitioner (NP), physician assistant (PA), or pharmacist (PharmD).  

As of now, 23 states and the District of Columbia have legalized adult-use cannabis for recreational purposes. Often, in these markets, customers come in to purchase cannabis for medical reasons. In fact, a recent study has shown that over 54 percent of these customers are relying on dispensary staff to answer medical questions about the use of cannabis, while only about 3 percent of those patients have asked for input from their medical providers. This is a problem because, despite knowledge of their products in the dispensary and perhaps their own personal experience, dispensary attendants cannot and should not be giving medical advice.

If your physician agrees that you could benefit from medical cannabis but doesn’t do certifications for medical cards themselves, then states that have approved its medical use will usually have a list of cannabis physicians that can certify you for use and guide you through therapy.  And that means not just approving you for use in a 10-minute conversation. 

What to know about the pharmacology of cannabis


A good cannabis clinician should take the time to review your medical records and spend time explaining our endocannabinoid system and how cannabis interacts with it, how it may help your specific medical condition, as well as making sure you will not have any drug interactions with other medications you are taking. They should be willing to follow up with you and be available to answer your questions once you start using medical cannabis. 

There should be a thorough review and discussion of your medical history, medical records, and any prescription medications you are already taking. They should discuss potential benefits and risks as outlined in the medical literature. There should be a discussion on the endocannabinoid system, which is our own internal cannabinoids that our body produces. As well as how phytocannabinoids (the cannabinoid compounds found in the cannabis plant) interact with our endocannabinoid system. 

There should also be a simplified explanation of the pharmacology of cannabis, which would inform you about how your body handles oral formulations versus inhaled cannabis. Inhaled cannabis has a quicker onset of action, taking seconds to minutes to feel the effects.  Inhaled cannabis has a shorter duration of effects, approximately lasting 4-6 hours.  Whereas oral cannabis can take 30 minutes to two hours before you may feel the effects, and these effects can last for 12-24 hours. 

All oral medications are digested and broken down in the liver to undergo detoxification called first-pass metabolism. Oral THC medications are also broken down in the liver into a chemical metabolite called 11-hydroxy-THC. And this can be more potent with longer-lasting intoxicating effects than THC itself. 

Additionally, you should be informed about the different timing of effects that one might feel when using oral versus inhaled formulations of cannabis. Oral cannabis takes longer for you to feel any effect, and the effects last longer than inhaled cannabis. There is a greater potential for overdosing with oral formulations such as edibles; often, people do not wait long enough to notice effects, and they might take a second dose before the first one kicks in. You need to be aware that THC levels in cannabis today are more potent than they were 20 years ago, and this, too, may result in a larger than intended dose even when smoking or vaping. 

You should be informed about the range of signs and symptoms of cannabis intoxication from an overdose, which includes nausea, vomiting, tachycardia (high heart rates), tachypnea (high respiratory rate), hypertension (high blood pressure), confusion, trouble walking, anxiety, paranoia, and delirium. 

You should be given information on the risk of falls and motor vehicle accidents when using cannabis. A good cannabis doctor can guide you on responsible use and help you find formulations such as CBD-dominant during the day and THC-dominant during the nighttime, which can help mitigate some of those risks while still maintaining the therapeutic benefits. 

Using a proper ratio of CBD to THC may mitigate and counteract the intoxicating effects of THC. CBD can bind to a different region on the cannabinoid receptor, causing a decrease in the binding of THC.  You should also consider starting your trial on a weekend when you are home with someone else around. 

Another potential risk they should discuss with you, especially if you have young children at home, is an unintentional overdose in kids. This is because many edibles look like delicious candy. It is important that all medications are kept locked up in a safe place away from children to prevent accidental pediatric exposures. 

A cannabis clinician should evaluate you for any potential drug-drug interactions. Since oral cannabis is broken down in the liver, it can interfere with the liver, breaking down your other medications, and it may cause toxic levels of those medications. Often, taking your cannabis doses within a two-hour window, either before or after your regular medications, can help mitigate this risk. 

Discussing dosage

Lastly, there should be a discussion about when to seek help in the emergency department if an overdose or bad adverse reaction occurs. Obviously, anyone having potentially serious or life-threatening symptoms such as chest pain, intractable vomiting, and dehydration needs to be seen in the ER. However, some people who take too much may just need to seek medical attention due to agitation or anxiety, which can be a frightening experience.  

For most adults, you just need supportive care, a safe, calm environment, and time to metabolize the cannabis dose. It can be in the hospital for observation or just at home with a caring, watchful family member. Luckily, an overdose of cannabis does not cause fatal respiratory arrest like seen with opioids because there are not many cannabinoid receptors in that part of the brain controlling breathing.

Medical cannabis therapy is very personalized, you need to have some patience. Unlike conventional medicine, where you take a one-size-fits-all pill, you must find the correct dosing that works for you; everyone reacts a little differently. 

While cannabis does have a wide safety margin, literature supports the use of the lowest effective dosage of cannabis. The famous adage that all cannabis physicians recommend is, “Start low and go slow.”  That means starting at a low dose and then slowly increasing the dose over time, every 3-5 days.  

It is imperative you keep track of the type of cannabis you are using, the dose you are using, and the effect you feel on a log sheet, either manually or on an app available online. While a good cannabis physician should recommend the initial starting dose, usually, cannabis naïve patients start with 0.5-1mg of THC dominant products and 2.5-5mg of CBD dominant products. 

But remember, you are the one in charge of finding that optimal dose and product that works for you and your medical condition. Therefore, you need to keep meticulous records and follow up with your cannabis physician often, especially in the early period. 

Got cannabis questions? Ask Doctor Leigh. Send your questions to GreenState’s Editor Rachelle Gordon at and keep an eye out for new answers from Dr. Leigh Vinocur every month.

Dr. Leigh Vinocur is a board-certified emergency physician who also has a cannabis consulting practice for patients and industry. She is a member of the Society of Cannabis Clinicians and a graduate of the inaugural class, with the first Master of Science in the country in Medical Cannabis Science and Therapeutics from the University of Maryland School of Pharmacy.

The response to this question was not written or edited by Hearst. The authors are solely responsible for the content.