Updated on January 29, 2019. Medical content reviewed by Dr. Joseph Rosado, MD, M.B.A, Chief Medical Officer
“While medical marijuana offers several benefits to patients, such as pain relief, it also poses several side effects, like many other medicines available today. One side effect some patients have experienced when using medical weed is fainting.
Additional 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, they weigh the potential side effects of medical marijuana for your condition and consider your medical history to predict how you may respond to medical weed.
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 weed in the evening, as it can cause drowsiness.
How Does Medical Weed Cause Fainting?
Fainting from medical weed is caused by several 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 pot. That decrease in blood pressure, however, can cause an increased heart rate and, in some cases, fainting.
- 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.
While standing doesn’t affect how medical weed interacts with your mind, it can make you more prone to fainting. . . . . ”
Source: Fainting from Cannabis | Medical Marijuana Side Effects
“One night in 2005, at a party at my house, two things happened: I had a single toke from a joint, and a friend introduced me to her new boyfriend. For most people this confluence of events would be no problem, but my body was not having it. As my friend’s boyfriend dribbled on about his adventures in Peru, his fluffy hair began to morph and swirl. The more it swirled, the more I wanted to vomit. Then his voice started piping down through a tiny hole in the roof, then… nothing. It was lights out. That was the first time it happened, but soon enough it became apparent that this was my fate. I could not inhale marijuana—not even a little bit, not even sans alcohol—without blacking out. But why? Is my constitution so delicate, just a whiff of weed requires its total shut-down?”
One of the only studies conducted on this phenomenon was published in 1992. Researchers from Duke University gave ten healthy men a strong joint to smoke while standing up, and reported that six participants felt “moderate” to “severe” dizziness. Those who experienced severe dizziness also showed marked decreases in blood pressure, which went as low as 60 mmHg.
The standing-up part is key because it indicates weed could bring on something called orthostatic hypertension, low pressure caused by the movement or position of the body.
“Marijuana can cause quite profound lowering of blood pressure, and cause users to faint as not enough blood gets to the brain,” confirms Dr. Andrew Mongomery, a general practitioner. “A lesser lowering of blood pressure may lead to a sense of dizziness without actually passing out, [although] the biological mechanisms underlying this are highly complex and incompletely understood.”
Source: Why Does a Single Hit of Weed Make Me Faint? – VICE