By Alan Shackelford, M.D..
Marijuana has been used to treat nausea for years. Nonetheless, because marijuana was found to be so effective in treating nausea with so few undesirable side effects, two prescription medications consisting of synthetic THC analogues were developed to treat nausea and wasting from HIV/AIDS and from cancer treatments. Dronabinol, which is sold under the trade name Marinol, is a synthetic form of THC and was initially approved by the FDA in the mid-1980s. A similar medication called nabilone, sold under the name Cesamet, has been available in the U.S. since 2006. But Marinol and Cesamet have been less than successful, in part because synthetic THC can cause much more intense and potentially debilitating psychoactive effects than those experienced with marijuana itself, while in some cases not as successfully treating nausea as botanical cannabis. In several studies, a majority of patients preferred natural cannabis to Marinol, in large part due to those intense psychoactive effects which are thought to be due to the absence of the other cannabinoids found in natural marijuana that moderate the effects of THC.
Despite the much greater functional impairment that can result from Marinol and nabilone, FDA-approved prescribing guidelines advise patients that they may drive or operate machinery once they know how it affects their performance. Marinol and nabilone can also be very expensive, with prices ranging up to hundreds of dollars a month.
A variety of different side effects have been seen with other prescription antiemetics, many of which are derived from medications used to treat psychiatric illnesses. These include agitation, changes in vision, nervousness, tremors, seizures, catatonia, muscle spasms, pseudo-Parkinsonism and difficulty swallowing, as well as irreversible rhythmic arm, leg and facial movements called tardive dyskinesia, and, rarely, a serious condition called neuroleptic malignant syndrome which can be fatal.
Natural marijuana can have side effects (euphoria, short-term memory loss, etc.) as well, all of which resolve quickly and become much less likely or are better tolerated after even short-term use of cannabis
It is important to note that cannabis and synthetic cannabinoids have not been compared with newer anti-nausea medications such as serotonin receptor antagonists and a protachykinin antagonist called aprepitant that are sometimes used in combination with powerful steroids to prevent nausea. Not even these new medications, however, are effective in all patients and that a relatively large number of them use cannabis when even these medications fail.
Alan Shackelford, M.D., graduated from the University of Heidelberg School of Medicine and trained at major teaching hospitals of Harvard Medical School in internal medicine, nutritional medicine and hyperalimentation and behavioral medicine. He is principle physician for Intermedical Consulting, LLC and Amarimed of Colorado, LLC and can be contacted at Amarimed.com.
