Medical marijuana is now legal in 38 states across the country, and millions of people rely on it for mental and physical health conditions. It offers several benefits to patients, such as pain relief, but it also poses several side effects. One side effect some patients have experienced when using medical weed is fainting.

Does Medical Cannabis Cause Fainting?

Also known as “vasovagal syncope,” fainting can happen to a small percentage of people who try marijuana. It’s a rare experience, but it can be scary to go through regardless.

Fainting from medical cannabis is caused by a couple of factors, including:

  • Blood pressure: One of the cannabinoids found in medical cannabis, tetrahydrocannabinol (THC), is a vasodilator, which means it expands your blood vessels — this is one reason patients with high blood pressure use medical marijuana. That decrease in blood pressure, however, can cause a slowed heart rate. Blood flows downward into the legs and away from the brain, causing a brief loss of consciousness. 
  • Administration: When you smoke or vaporize medical marijuana, you feel the effects faster. In comparison, edibles and oils need more time to take effect. So, if you smoke medical cannabis, you may experience a sudden drop in blood pressure, which can surprise your body and result in fainting.

Standing while smoking doesn’t affect how medical marijuana interacts with your mind and body, but it can make you more prone to fainting.

Signs of Fainting From Medical Cannabis

There are a few key signs that you may be about to experience a fainting episode. If you experience any of these, move to a comfortable place in case you pass out.

Signs you may be about to faint include:

  • Feeling dizzy
  • Shortness of breath
  • Sweating
  • Nausea
  • Headache
  • Blurred vision

If you’re at home with loved ones, they may notice you becoming pale or unresponsive before fainting.

Other Potential Side Effects of Medical Marijuana

For medical marijuana physicians, the goal is to ensure you’re receiving treatments that offer you the maximum benefit. Because of that, doctors weigh the potential side effects of medical marijuana for your condition and consider your medical history to predict how you may respond to medical marijuana.

In some cases, you and your doctor may decide to incorporate medical cannabis into your treatment plan because of its side effects. People with insomnia, for instance, have benefited from using medical cannabis in the evening, as it can cause drowsiness.

Other side effects of cannabis are less helpful and may simply be an annoyance. These can include red or bloodshot eyes, dry mouth, dizziness, nausea, or paranoia.

Long-Term Side Effects of Fainting

In most cases, fainting doesn’t cause any long-term side effects. The most significant risk of fainting, whether it’s after giving blood, standing up too fast, or using medical cannabis, is harming yourself when collapsing, such as by hitting your head. If this happens, don’t hesitate to go to the hospital. Should you faint on multiple occasions, it could be a sign of a more serious heart-related condition.

How to Prevent Fainting From Medical Marijuana

For most patients, fainting isn’t a tolerable side effect, and physicians agree. Because doctors understand why medical marijuana can cause fainting, they’ve developed several techniques for preventing it, including:

  • Switching your strain: Since THC acts as a vasodilator, choosing a strain with low THC and high CBD content can limit its effects on your blood vessels, which then minimizes the chance of fainting. Your doctor or budtender may be able to recommend a specific strain for your condition.
  • Administering your medicine sitting down: Compared to sitting, standing places you at a higher risk of fainting. In fact, remedies for preventing fainting suggest sitting or lying down. Having fresh air, such as a breeze from an open window, can also help you avoid feeling faint.
  • Switching to another method of administration: If smoking or vaping cannabis is causing you to faint, trying a more slow-acting form of cannabis, such as edibles, oils, or tinctures, may help.

If you’re having fainting spells when you use cannabis, consult with your physician before altering your treatment plan.

Can Cannabis Help Prevent Other Causes of Fainting?

Unfortunately, there is little research done at the moment on whether or not cannabis can prevent other types of fainting, such as cardiac syncope or neurologic syncope. Some of the most common causes of fainting include heart problems, stress, dehydration, low blood sugar, and anemia.

While cannabis can help with certain causes of fainting, such as anxiety or stress, it may worsen these issues in others. If you have chronic fainting issues, talk to your doctor to determine the cause. If it is something that medical cannabis can help with, your doctor can help you form a treatment plan that includes marijuana.

Talk to Your Medical Marijuana Doctor About Your Fainting

Because physicians understand the cause of fainting from medical marijuana and how to prevent it, it’s often still beneficial for patients to continue their treatment. However, it’s crucial that you continue meeting with a licensed, knowledgeable, and compassionate medical marijuana doctor to discuss your symptoms and make any potential changes to your treatment.