Pumping the Brakes on Medical Marijuana
A timely and important article in the New England Journal of Medicine offers two competing perspectives on the role of medical marijuana for patients with chronic pain. The first author argues that medical marijuana should become an important part of the arsenal for chronic pain. He writes: “Provided that the patient is informed about the risks of combustion-related toxins and educated about how to abate the potential discomfort of inadvertent overexposure to tetrahydrocannabinol (e.g., by administering cannabidiol) … trying this treatment carries negligible risk. At a minimum, [patients with chronic pain] can expect moderate analgesia, reduced allodynia, muscle relaxation, a reduced stress response to her disability, and an empowering level of control over mood in coping with her illness.” Indeed, we have heard numerous anecdotal reports, including from many of our own patients, about the value of marijuana for pain and many other ailments. Some patients insist that marijuana is the only therapy that addresses bothersome symptoms, such as pain and nausea.
But in the second viewpoint, the author highlights just how scant the data on medical marijuana is. He writes: “Literature reviews on the efficacy of medical marijuana are cautionary about effectiveness and side effects… studies in humans that suggest efficacy are limited in quality and scope … Commonly reported side effects of cannabinoids include sedation, dizziness, dry mouth, dysphoria, appetite stimulation, and short-term memory loss, all of which can interfere with established treatments such as rehabilitation and psychological therapies. Long-term exposure to cannabis has also been associated with a risk of psychotic disorders, including the emergence of latent schizophrenia in a dose-dependent manner, particularly in persons with a preexisting vulnerability.”
In the midst of the opioid crisis our society is now facing, there is tremendous need for effective alternative therapies for pain. Medical marijuana may be one of the most promising treatment alternatives to opioids. But until rigorous studies establish its safety and efficacy, we cannot in good conscience recommend its widespread use. History provides too many cautionary tales of harm resulting from precocious exuberance based on anecdotal reports.
Fewer PAP Smears Needed
The single most important screening advance in the past two decades has been the use of high-risk human papillomavirus (hr-HPV) testing for cervical cancer screening, and the benefits for patients continue to accrue.
According to the latest US Preventive Services Task Force recommendation published this August in the Journal of the American Medicine Association, women age 30 to 65 years may be screened either with hr-HPV testing and Pap co-testing every five years (as previously recommended) or can now be screened using only hr-HPV every five years without Pap co-testing. Modeling studies for women in this age cohort suggest that co-testing provides slightly greater protection against death from cervical cancer (.29 vs .3 deaths per 1,000), preventing one women dying from cervical cancer for every 100,000 screened. For most women, the additional risks of increased testing and diagnostic procedures involved with co-testing will not be worth the small potential benefit.
The Slow Medicine approach will be to start by recommending hr-HPV testing every 5 years to women at average risk of cervical cancer age 35 to 60 years, but we will also support the request of women who choose to pursue co-testing once they have considered the risks and benefits.
As a reminder, the USPSTF still recommends a Pap smear every 3 years for women age 21 to 29 years. But this recommendation might change in the near future for women who have previously received HPV vaccination, as we are undoubtedly performing too many Pap smears in this subgroup of women as well.
Procalcitonin Testing Versus Clinical Judgment
Whether procalcitonin-guided therapy improves care of patients with lower respiratory tract infections remains an area of active debate. A series of European studies have provided evidence that using procalcitonin to help guide decisions regarding the use of antibiotics when caring for patients with suspected lower respiratory tract infections can decrease antibiotic use. In fact, these studies have led the FDA to approve procalcitonin testing for this indication. However, a new study published in the New England Journal suggests that this approach may not be effective in the U.S.
In the study, more than 1,600 patients presenting with respiratory symptoms to 14 emergency departments at U.S. hospitals were randomized to procalcitonin testing versus usual care. The investigators did not find any significant differences between the procalcitonin group or the usual-care group in exposure to antibiotics (measured in “antibiotic-days,” mean 4.2 vs 4.3 days).
We wonder if this disappointing result might be explained by the fact that clinicians may use procalcitonin testing to justify antibiotics in equivocal situations just as frequently as the test is used to avoid inappropriate use. Most importantly, the study was not large enough to determine the more important question: whether one group fared better than the other with respect to hard clinical outcomes.
Avoiding unnecessary antibiotics can prevent unexpected adverse effects. A safety alert from the FDA this summer, for example, cautioned that fluoroquinolones’ may cause hypoglycemia along with disturbances in attention, disorientation, agitation, nervousness, memory impairment, and delirium. Still, it seems that old fashion clinical judgment may be just as effective as procalcitonin testing in guiding the decision about whether or not to prescribe antibiotics.
Pieter Cohen, MD, is a general internist at Cambridge Health Alliance in Somerville, Massachusetts and Associate Professor of Medicine at Harvard Medical School. Michael Hochman, MD, MPH, is a board-certified general internist who attended Harvard Medical School.