Medical marijuana: An oxymoron and a risk to fetuses
Dr Lockwood, editor in chief, is Senior Vice President, USF Health, and Dean, Morsani College of Medicine, University of South Florida, Tampa. He can be reached at [email protected].
In a time marked by a conservative lurch of the American electorate, and mounting state and federal legislative efforts to restrict access to family planning, voting, and union collective bargaining, there has been a paradoxical nationwide loosening of laws proscribing marijuana use. Twenty-eight states and the District of Columbia have now decriminalized personal marijuana possession. Moreover, the percent of US adults who perceive great risk from marijuana usage has declined from 51.7% in 2003 to 33.3% in 2014.1 Interestingly, Americans have not only become increasingly inured to potential risks, they have also enthusiastically embraced putative “medical” uses of cannabis.
Indeed, without substantive scientific evidence for their action, 29 states and the District of Columbia have now legalized medical marijuana.2 My own state of Florida—which voted for Donald Trump, returned a large GOP majority to the state legislature, and has a Republican Governor—enthusiastically passed a medical marijuana referendum this past November (6.5 million votes in favor vs 4.6 million against). Ironically, the biggest supporters of the pro-cannabis referendum were reliably conservative farmers, tobacco interests, and land developers, all of whom stood to gain financially from the plant’s cultivation. While aging hippies and libertarians may be heartened by this trend, obstetricians should be concerned.
Efficacy of medical marijuana
There is de minimus evidence supporting the pharmacological value of cannabis. Whiting and associates recently conducted a systematic review and meta-analysis of studies examining the risks and benefits of cannabinoid therapies.3 Of 79 trials identified, only 4 were judged to be at low risk of bias. Compared with placebo, marijuana resulted in a greater complete nausea and vomiting response among those undergoing chemotherapy with an odds ratio (OR) of 3.82 (95% CI: 1.55–9.42; 3 trials). Among chronic pain patients, the average number of patients reporting a ≥ 30% reduction in pain was slightly greater with cannabinoids than with placebo (OR, 1.41; 95% CI: 0.99–2.00; 8 trials). However, common side effects included dizziness, dry mouth, fatigue, somnolence, euphoria, disorientation, drowsiness, confusion, loss of balance, hallucination and, interestingly enough, nausea and vomiting. Given the excellent new antiemetics on the market and the myriad of analgesics, these “benefits” are hardly notable. Moreover, cannabis did not reduce rates of depression or improve intraocular pressure among glaucoma patients. At best these studies suggest that additional trials may be warranted in highly select populations but they certainly do not support the sale of this drug for any legitimate pharmaceutical purpose.