Does medical marijuana treat glaucoma? And other common misconceptions, explained

Weed, pot, grass, chronic, reefer—whatever you call it, there’s a nearly 100 percent chance either you or someone you know has used this drug before. A whopping 22.2 million Americans have used it in the past month alone and 52 percent of adults have used it at least once in their life, making it the most commonly used illicit substance in the U.S.

The drug we’re talking about is cannabis (or, “marijuana”). Because despite its federal designation as a Schedule I drug – a classification reserved for substances having “no accepted medicinal use and a high potential for abuse” – public opinion about marijuana use has shifted drastically in recent years. In 1972, just 15 percent of Americans thought marijuana should be legal. Today, that approval rating has climbed to over 50 percent in the general population.

And support for medical marijuana is even higher. In 2016, one poll found that the majority of Americans (89 percent) are in favor of “allowing adults to legally use marijuana for medical purposes if their doctor prescribes it.” And nearly 70 percent of doctors support making it available as a treatment option for patients, according to a 2014 WebMD survey.

So, which is it? Is marijuana a dangerous drug on par with heroin, as its Schedule I classification would suggest? Or is it a safe, legitimate treatment option for patients living in the 30 states where it has already been decriminalized?

With all these conflicting signals, it’s no wonder patients are confused. Read on for more about how medical marijuana is already helping patients, the most common misconceptions surrounding its efficacy, and how you can talk to inquiring patients about this controversial treatment option.

How medical marijuana helps cancer patients

It’s no coincidence that among doctors, oncologists rank highest in support of using medical marijuana as a treatment option. That’s because numerous drug trials have shown cannabinoids (the psychoactive compounds present in cannabis) to be more effective than traditional antiemetics in curbing sickness brought on by chemotherapy.

One study in particular, however, noted that even though patients taking cannabinoids experienced significantly more positive side effects, they also reported more negative side effects such as paranoia.

All things considered, the use of cannabis in “combatting…chemotherapy-induced nausea and vomiting, [and] pain” has been well researched and is generally accepted. But as with any other treatment, patients should be made aware of the potential adverse side effects.

For other ways to support patients managing chronic disease, see Top Three Strategies to Help Patients Managing Chronic Disease

Medical marijuana’s potential role in the opioid epidemic

Could medical marijuana help curb the opioid epidemic? A 2012 study of patients prescribed medical marijuana for chronic pain in Hawaii uncovered promising results in support of this hypothesis. Of the 94 patients who responded to the survey, 64 percent reported a decrease in pain overall, 71 percent reported no adverse effects of using marijuana, and zero percent reported any serious adverse effects – suggesting that it can be both effective and safe in treating chronic pain.

Additionally, a retroactive analysis from JAMA Internal Medicine found a nearly 25 percent lower opioid overdose mortality rate in states where medical marijuana is legal compared to states without legalization laws. The implications of these findings are particularly relevant considering the severity of the current opioid epidemic that claims 91 Americans every day.

While the evidence seems promising, a recent systematic review of 27 chronic pain trials reminds us that because most of this research has studied patients with neuropathic pain, the results cannot be generalized to patients with other types of chronic pain.

If you’re practicing in a state where medical marijuana is legal, it’s best to have an open and honest conversation with patients about all of their treatment options.

To learn more about treating patients with chronic pain, see Why Successful Pain Management Requires Trust

Why medical marijuana is not recommended for treating glaucoma

Although commonly accepted by the general public, the notion that medical marijuana can help treat glaucoma has been regularly debunked by doctors and researchers. The fallacy was born in the 1970s when researchers found evidence that marijuana can help lower intraocular pressure (IOP) – but only for periods of three to four hours at a time. In other words, as Invision Magazine notes, glaucoma patients would have to maintain a pace of smoking at least eight to ten joints daily in order to experience lasting relief.

The American Academy of Ophthalmology goes on to explain that, “marijuana not only lowers IOP, but it lowers blood pressure throughout the body. As a result, it has the potential to lower the blood flow to the optic nerve, effectively canceling out the benefit of a lowered IOP.”

To date, no long-term studies have been conducted to study the lasting effects of cannabis on glaucoma—and researchers have just begun to explore how regular marijuana use affects other parts of the eye, such as the retina. Ophthalmology Times recommends that doctors explain to curious patients that, “marijuana does not replace ongoing glaucoma therapy and that regular monitoring for glaucoma should still be continued.”

For ideas on how to properly educate your patients about this important eye health condition, see Six Ways to Improve Glaucoma Awareness

Medical marijuana’s effect on anxiety, depression remains inconclusive

The 2012 study of patients prescribed medical marijuana for chronic pain in Hawaii also revealed interesting implications for the treatment of mental illness. Half of the same 94 respondents experienced a decrease in anxiety, while 45 percent reported insomnia relief.

There is evidence to support the opposing theory as well – that marijuana can exacerbate some mood disorders – but the data has so far been correlational rather than causational. Such conflicting evidence exists because drug use has consistently found to be higher among those with mental illness, making it especially challenging for researchers to untangle the true relationship between the two.

To learn more about addressing patients’ behavioral health needs, see Why Behavioral Health Is Every Doctor’s Business

Tips for talking to qualified patients about medical marijuana

Since medical marijuana laws vary from state to state, it’s important to help patients understand what conditions qualify for a cannabis prescription.

For doctors practicing in states where medical marijuana is legal, don’t wait for qualified patients to ask about a prescription. There is still a negative stigma surrounding marijuana use that may make it difficult, awkward, or embarrassing for patients to bring up. Instead, present the option (when applicable) alongside your other treatment recommendations. You might also provide patient education materials in your office so curious patients can get the information they need to make an informed health care decision.


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