The closest exposure most pharmacists have to medical marijuana products in their day-to-day practice is likely to be with cannabinoids, such as dronabinol (Marinol, Syndros, THC) or the newly approved cannabidiol (CBD; Purified CBD, Epidiolex), according to William Kirchain, PharmD, CDE, Wilbur and Mildred Robichaux Endowed Professor at Xavier University of Louisiana College of Pharmacy. True medical marijuana, he says, refers to herbal products, which are sold through either marijuana dispensaries or specialty permitted marijuana pharmacies.
CBD and tetrahydrocannabinol (THC) are two natural compounds found in Cannabis, the marijuana plant. CBD does not cause the “high”; that comes from THC, which is the primary psychoactive component of marijuana.
While pharmacists must counsel patients thoroughly when they dispence Epidiolex or Marinol, all pharmacists should also be discussing medical and recreational use of marijuana with all their patients because marijuana can interact poorly with certain prescription medications and over-the-counter medications.
Studies indicate that more Americans are trying marijuana for recreational use and medicinal purposes as laws surrounding marijuana use have become more liberal. At press time, 31 states, and Washington, DC, allow comprehensive public medical marijuana and cannabis programs. Of those, nine have approved marijuana for recreational use.
Each state has its own laws about how patients can access medical marijuana.
In a controversial move, back in June 2018, Oklahoma voters voted to made it legal to use, sell, and grow marijuana for medicinal purposes in a referendum (State Question 788). The referendum passed despite pushback from conservative politicians and law enforcement groups.
Medical Marijuana Use Is Increasing
Estimates of past-year marijuana use has increased for middle-aged and older adults, according to a study published in Drug and Alcohol Dependence. The analysis comes from data gathered in the National Survey on Drug Use and Health from 2015 and 2016. About 9% of U.S. adults between ages 50 and 64 used marijuana in the previous year, according to survey results. About 3% of people over 65 used the drug in that time period.
In the 2016 study, almost one-quarter of Americans over age 65 who had used marijuana in the previous year said they received permission from their physicians. A January 2017 research overview published by the National Academies of Science, Engineering, and Medicine, showed that a still small but growing number of studies suggest that marijuana may be helpful in treating pain, nausea, and spasticity.
Medical marijuana can be marketed and sold in a variety of forms, as the properties of THC and CBD are used to produce a desired therapeutic response, Scott Tomerlin, PharmD, APhA spokesperson. Some of the latest trends in medical marijuana include the use of CBD oil in a variety of topical and oral preparations, he says.
“Other products that have gained popularity over recent years have included the use of hemp seed oil as well as the use of products containing CBD for veterinary use. E-cigarettes and other products which allow CBD to be inhaled in a vapor form, otherwise known as ‘vaping,’ are becoming increasingly popular on the marketplace as well,” he says.
There are more than 40 compounds in common CBD oils and extracts, and these products may vary in potency by a substantial amount even batch to batch. Some states allow use of “low THC, high CBD” products for medical reasons in limited situations.
Marijuana is metabolized through the liver, primarily through the CYP450 enzyme system, specifically 2C9, and 3A4 pathways, according to Deborah A. Pasko, PharmD, MHA, senior director for Medication Safety and Quality with ASHP.
“Drugs that undergo these same metabolic pathways are at risk of having a drug-drug interaction with marijuana. If the non-THC drug is an inducer it will lower concentrations of THC. If the non-THC drug is an inhibitor then it will elevate concentrations of THC,” Pasko says.
Continue reading on page 2...