Medical marijuana not benign; it can poison


Recently I read a national article about a medical team that looked the other way while a patient was smoking marijuana in the bathroom. On a closer reading of the article, the medical case was from over 20 years ago. First mistake: not doing the math (we’ll get to this in a minute). Second mistake: concluding that the answer is “medical” marijuana.

Did you know that the two major compounds that are medicinal in marijuana are already 100 percent legal here in Kentucky?

It’s true. The Food and Drug Administration approved dronabinol (brand name Marinol) in 1985 for nausea and vomiting for chemotherapy patients and loss of appetite in AIDS. Dronabinol is delta-9- tetrahydrocannabinol (delta-9-THC), the main form of THC in marijuana.

The second compound in marijuana which appears to have medicinal value is also legal here: Gov. Steve Beshear signed a law in 2014 permitting cannabidiol to be sold.

Two important principles of medicine people completely get wrong about “medical”marijuana. No. 1: Penicillin was derived from mold, but if you have a bacterial infection I’m not going to give you moldy bread. No. 2: The difference between a medication and a poison is the dose.

Let’s talk about math. Cannabis in the 1970s was about 1 percent to 2 percent THC; in the 1990s, it averaged 4 percent THC. Modern-day cannabis averages around 12 percent THC.

This 12 percent stuff goes by several names amongst the college students I meet: “Reggie” or “regular,” but most people using “medical” marijuana are smoking products that are up to 30 percent THC. If someone is smoking one gram of “chronic” “skunk” or “loud” plant material that’s 1000 mg times 30 percent THC equals 300 mg THC.

Consider that dronabinol comes in doses of 2.5 mg to 10 mg capsules, and that the FDA lists a maximum daily dose as 20 mg. My point is that most people who are smoking cannabis are overdosed on it, and there are alternatives.

In the case mentioned above from 20 years ago, let’s say he was using one-half gram of cannabis (one joint), which likely contained 20 mg THC (500 mg times .04). With the strong “medical” cannabis that people use today that would range from 60 mg to 150 mg (500 mg times 12 percent to 30 percent).

Assuming all other prescription medications had already failed it would be reasonable to try someone who was a chronic user on higher doses (lets say 20 mg to 30 mg) of dronabinol (and a taper of cannabidiol as well). There’s a good chance a heavy cannabis user would experience cannabis withdrawal going from 150 mg a day to 30 mg a day. By the way, marijuana can also cause nausea in cases of high (pun not intended) dose usage.

The delivery method is worth noting as inhaled THC seems to have a very different absorption profile than orally administered dronabinol, which appears to have some inconsistent results from patient to patient.

This takes the debate back to public funding for research into drug delivery, rather than letting the commercial sector (or black market) develop habit-forming products that are marketed to children. As an aside: there is an interesting historical parallel in how humans bred tobacco to have more nicotine, and now cannabis with THC.

We need more research; I’d also like to see some guidelines for off-label use of dronabinol.

As far as “medical” marijuana goes, the debate will continue, I’m certain. Hypothetically speaking, if Tylenol doubled the rate of schizophrenia and bipolar disorder do you think there would be any debate about taking it off the shelves?

In my line of work I’ve definitely seen cases where cannabis caused side effects, including psychosis.

Dr. Matthew Neltner is a Lexington physician.