MS Speaks

Neurology

Marijuana for MS. Now What?


By John Gever, Deputy Managing Editor, MedPage Today


Medical marijuana got a big boost last week, perhaps the most significant ever. The American Academy of Neurology issued a new practice guideline that gave a qualified endorsement to certain cannabis-based products for controlling particular multiple sclerosis symptoms. [see http://msspeaks.createaforum.com/treatments/aan's-new-guidelines-on-effectiveness-of-cannabis-other-cam-treatments/

"Strong evidence" backs up a recommendation that physicians "might offer oral cannabis extract" to reduce subjective complaints about spasticity and non-neuropathic pain, the AAN said -- though it noted that cannabis products don't appear to reduce objective measures of spasticity, although the evidence against an effect is only modest.

The Sativex oral cannabinoid spray, which is not yet FDA-approved but is available in many other countries, also received the AAN's endorsement for treating spasticity and pain, as well as for reducing urination frequency (but not incontinence).

But with Sativex unavailable in the U.S., the practical impact of the new guideline remains uncertain, even in locations where medical cannabis is ostensibly legal.

In the Vanguard

As it happened, last week I was in Colorado, the only state where marijuana is now legally sold both for medical and recreational use. (Voters in Washington state approved similar legislation in 2012, but recreational sales were put on hold while regulations were developed; sales are supposed to begin by the end of June.)

Medical marijuana still exists in Colorado -- it's regulated separately and, more important, it's cheaper for buyers than recreational pot products because the latter are subject to a special 15% excise tax. Thus, individuals seeking marijuana for its medicinal properties have a strong incentive to stick with the medical marijuana system, which has been in place in its present form since 2011.

It requires patients to obtain an ID, known as a "red card," that entitles them to purchase cannabis products from licensed dispensaries. Not just anybody can get a red card -- a physician must declare that a patient has one or more of eight "qualifying conditions." These include cancer of any kind, glaucoma, or HIV infection, as well as those with the following 5 symptoms: cachexia, seizures, severe nausea, severe pain, or persistent muscle spasms. MS-related spasticity falls under this last category.

A physician must also supply a "recommendation" -- not a prescription per se, because that would be illegal in the absence of federal approval -- that the patient obtain medical marijuana for his or her specific condition.

One might wonder how the products themselves are regulated -- assuring users that the bag of flowers or the vial of extract that they are buying meets the most basic labeling and safety standards.

Since marijuana plants and extracts remain illegal at the federal level, there is no FDA or other national oversight, meaning it's up to the states. And Colorado is struggling with the responsibility.

Currently, regulation of growers and vendors rests with the state's Department of Revenue. Its primary focus is on ensuring that these businesses pay their required fees and taxes and they aren't run by known criminals -- not on product quality or safety.

Larry Wolk, MD, MSPH, executive director of the state's public health department -- who has only been in the job for 6 months -- said he wants to apply the usual food safety standards to both retail and medical marijuana.

But the agency has to develop this capability from the ground up -- the FDA and the USDA currently handle most food inspections -- even as marijuana cultivation, processing, and sales in Colorado are growing by leaps and bounds. Wolk said he was seeking a bigger cut of marijuana-related revenues to fund this and other needs arising from the legalization, such as monitoring for adverse health effects.

Colorado isn't alone in trying to figure out what to do with medical marijuana. This week, the government of Canada essentially threw up its hands, passing responsibility for deciding which patients should be eligible for marijuana treatment to individual physicians.

The Canadian Medical Association is advising its members, in essence, to just say no. "Canadian physicians should be wary of 'prescribing' medical marijuana under [the] new regulations," its president said in CMAJ.

The regulations also changed patient access to cannabis products recommended by a physician. Whereas formerly patients could grow their own, now they must buy products by mail from a licensed vendor.

And Washington, the other U.S. state with legalized recreational sales, can't decide how to regulate medical uses. According to the New York Times, an effort to bring it under state control failed last month despite what had been seen as bipartisan support for some type of regulation.

On the Ground

In Denver last week, I visited several storefront dispensaries, some of which were still selling only to medical patients while others had opened their doors to recreational-use customers as well.

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Two shops in downtown Denver were both occupying small offices on the upper floors of older office buildings. Customers had to be buzzed in through a locked front door, then present their red card (for medical patients) to a receptionist before being allowed through a second locked door to the actual sales counter.

Patients who successfully navigate this far are then confronted with a bewildering array of cannabis products. Dispensaries frequently carry dozens of varieties of dried marijuana plant flowers and leaves, as well as extracts, oils, and "edibles" -- baked goods and candies containing cannabinoids. The newest thing is pre-filled e-cigarette oil cartridges that allow the active substances to be inhaled without exactly smoking them.

Each product has different mixtures of THC and other cannabinoid compounds, such as cannabidiol (CBD), which purportedly provides the pain and nausea relief expected from marijuana without the quasi-euphoric sensation. Products are sold as primarily Sativa (high in THC), Indica (enriched in CBD), or hybrids.

Kari Franson, PharmD, PhD, of the University of Colorado's pharmacy school, said that the pharmacodynamics of cannabinoids are extremely variable between people and even within in an individual over time, especially with oral dosing.

"Interpatient variability ... can be 10-fold," she said.

Of course, there is no peer-reviewed literature* to guide patients or physicians in choosing among these products, which change almost weekly as growers develop new strains and new processings. A patient new to marijuana must therefore rely on the dispensary staff for advice.

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Wolk told me that he would like to require some type of training and certification for the dispensary staff who counsel patients. That will require new authority, however, which the state legislature would have to approve.

* There is a literature, but it exists mainly in online forums and blog comments, and it's peer-reviewed only to the extent that it's all generated by users.

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"Striking a Nerve" is a blog by John Gever for readers interested in neurology and psychiatry.