JAMA Says Little Evidence Supports Marijuana for Medical Use

Evidence does not support medical marijuana use for most of the diseases and conditions states are permitting, says an editorial in this week’s issue of the Journal of the American Medical Association (JAMA).

“First, for most qualifying conditions, approval has relied on low-quality scientific evidence, anecdotal reports, individual testimonials, legislative initiatives, and public opinion,” say the editorial’s authors. “The US Food and Drug Administration (FDA) requires evidence from at least two adequately powered randomized clinical trials before approving a drug for any specific indication,” and evidence for most conditions fails to meet FDA standards.

Second, there are inconsistencies between states about which conditions qualify for medical marijuana. Some states legalize medical marijuana for PTSD or sickle cell anemia, for example, while others do not. Such differences reflect inconsistencies in applying current evidence to legislative decision-making.

Third, most FDA-approved  drugs have just one or two active ingredients. Marijuana contains more than 400 compounds whose interactions with each other are poorly understood. In addition, the amounts of some marijuana compounds in various strains vary so widely that precise dosing is difficult, which means doctors cannot give patients proper guidance.

Fourth, some individual marijuana components are available commercially (dronabinol and nabilone) and published data exists to guide dosing. Few data exist to guide dosing of smoked [or eaten] marijuana for medical use.

Fifth, while short-term adverse effects of marijuana are quite well known, the effects of long-term use need further study. Tolerance and dependence occur with repeated exposure to marijuana, meaning that dosages will have to be increased when the drug is used medically to be effective, increasing the risk of addiction and other problems.

Finally, “there is also a small but definite risk of psychotic disorder associated with marijuana use, as well as a significant risk of symptom exacerbations and relapse in patients with an established psychotic disorder,” say the authors. Those with schizophrenia, bipolar disorder, or substance dependence must be identified and measures must be taken to protect them from medical marijuana.

“Perhaps US states should establish clinical follow-up programs to monitor long-term outcomes prospectively, especially negative outcomes (e.g. new cases of psychosis) in patients with contraindications.”

In addition to this editorial, JAMA also publishes several research articles concerning medical marijuana this week.

Read editorial here.
Read “Medical Marijuana for Treatment of Chronic Pain and Other Medical and Psychiatric Problems, A Clinical Review” here.
Read “Cannabinoids for Medical Use, A Systematic Review and Meta-Analysis” here.
Read “Cannabinoid Dose and Label Accuracy in Edible Medical Cannabis Products” here.

Source:  The MarijuanaReport.org.   June 24th 2015

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