Medical marijuana laws still vary across the United States, and barriers persist for patients and providers, including fear of addiction and side effects as well as safety, financial, and legal concerns.

Carey Clark, PhD, RN, AHN-BC, of the University of Maine at Augusta, Jacquelyn Bainbridge, PharmD, FCCP, from the University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, and Lisa Kennedy Sheldon, PhD, APRN-BC, AOCNP®, FAAN, chief clinical officer at the Oncology Nursing Society, discussed the latest in medical marijuana laws and usage during a session at the 42nd Annual Congress in Denver, CO.

Sheldon began the session by detailing the history of medical marijuana. The use of cannabis dates back to 2727 BC by the Chinese emperor Shen Nung. It was also used in the 1800s by U.S. physicians to treat pain, cough, menstrual cramps, and more than 100 other illnesses. In the early 1900s, however, Americans feared losing their jobs to Mexican immigrants who were bringing marijuana into the United States. In the 1930s, the antimarijuana propaganda in the United States began to ramp up.

In the 1970s, the Controlled Substances Act declared marijuana a schedule I drug, which is associated with a high risk of abuse and discourages medical use. The War on Drugs in the 1980s further distanced the use of marijuana in the United States, until California became the first state in 1996 to legalize medical marijuana. Now, 25 states have medical marijuana programs, but the laws vary by state. Because of the drug’s continued schedule I classification, it is difficult to study, and the University of Mississippi is the only source for cannabis research in the United States.

Clark continued by discussing the nurse’s role with regard to medical marijuana. She noted a study published by Abrams et al. in Clinical Pharmacology and Therapeutics, which indicated that cannabis can be used in early palliation to help with pain, nausea, sleep disturbances, nutrition issues, and depression. In addition, cannabis is better than opioids for chronic pain, as there are fewer risks and less side effects; however, studies on this topic only include a small patient population because of the prohibition effect on the drug.

With the growing interest in using cannabis as an herbal palliative medicine, oncology nurses should assess patients’ palliative needs, prior history and/or current cannabis use, other palliative medicine, potential drug-drug interactions, financial implications for palliative care, support system, knowledge of ingestion methods and side effects, and any safety concerns.

In states that have medicinal marijuana laws, nurses should support patients in the process, indicating where and how to access cannabis (dispensary, caregiver, home-grown), ingestion methods (inhalation, dabbing, topical, transdermal, edibles, oils, tinctures, rectal), dosing and schedule (via a patient cannabis diary), and any side effects or medication interactions. “Know your state!” Clark urged with regard to the state-by-state laws and regulations.

She cautioned that the largest risk for drug-drug interaction with cannabis is medications that increase bleeding risk, such as aspirin, warfarin, heparin, clopidogrel bisulfate, and nonsteroidal anti-inflammatory drugs, because cannabis can also increase the risk of bleeding. Cannabis can also lower blood sugar, blood pressure, and the liver’s cytochrome P450 enzyme, which could impact how other herbal supplements and medications may be metabolized.

Side effects of cannabis can include dysphoria, anxiety, panic, impaired memory, decreased psychomotor performance, impaired cognitive capacity, tiredness, dizziness, tachycardia, drug mouth, dry eyes, and a distorted perception of the passage of time.

She finished by recommending that nurses remain educated on the laws surrounding medical marijuana and best practices for dosing and side effects, as well as advocating for patients and ending the stigma surrounding the use of medical marijuana.

Bainbridge concluded the session by expanding on drug-drug interactions with cannabis use. Tetrahydrocannabinol (THC), is the major psychoactive component of cannabis, is metabolized by CYP3A4 and CYP2C9, which has the potential for interactions with other CYP3A4 inhibitors and inducers. Cannabidiol (CBD) is extensively metabolized by the liver and is a potent inhibitor of CYP2C and CYP3A, and both THC and CBD are highly lipophilic.