ABSTRACT
BACKGROUND: With the legalization of cannabis in Canada in 2018, pharmacists are increasingly likely to encounter patients using this substance. The primary objective of this pre-post questionnaire study was to evaluate the impact of an accredited cannabis course on the understanding, beliefs, perceptions and knowledge of undergraduate PharmD students. METHODS: A 38-question, web-based survey generated in REDCap was administered to third-year PharmD students at the University of Waterloo, prior to and right after taking an accredited cannabis course. The pre- and postsurvey data were analyzed using SPSS version 25. Pearson chi-square tests were performed on questions in which answers consisted of qualitative categorical data. Two-sided t tests were performed to test the significance of mean differences of questions measuring continuous variables. RESULTS: In a class of 120 students, 110 completed the presurvey and 79 students completed the postsurvey. After the course, students were more likely to report being knowledgeable and prepared for patient encounters dealing with medical and recreational cannabis, understanding that medical cannabis should be prescribed for select (vs all) medical conditions, rating the quality of evidence as poor to moderate for medical use of cannabis, understanding that medical documents should be more prescriptive and understanding that cannabis should not be sold in pharmacies (p < 0.05). INTERPRETATION: With cannabis education a part of their curriculum, pharmacy students felt more prepared to engage patients using cannabis both medically and recreationally. Furthermore, students were more cautious regarding the potential use of cannabis therapeutically and indicated that more oversight should be in place. Can Pharm J (Ott) 2021;154:xx-xx.
ABSTRACT
BACKGROUND: Cannabidiol (CBD) serves as a promising medicine, with few known adverse effects apart from the potential of drug interactions with the cytochrome P450 system. It has been hypothesized drug interactions may occur with chemotherapeutic agents, but no supporting evidence has been published to date. CASE: A 58-year-old female with a history of bilateral breast carcinoma in remission, was treated with tamoxifen for breast cancer prevention for over 6 years. CBD was instituted to treat persistent postsurgical pain, inadequately managed by alternate analgesics. It was postulated that CBD may diminish tamoxifen metabolism by CYP3A4 and 2D6 to form active metabolite endoxifen, which exerts the anticancer benefits. Endoxifen, tamoxifen, N-desmetyltamoxifen and 4-hydroxytamoxifen levels were collected while the patient chronically received CBD 40 mg/day, and after a 60-day washout. Upon discontinuation of CBD 40 mg/day, it was observed that endoxifen levels increased by 18.75% and N-desmethyltamoxifen by 9.24%, while 4-hydroxytamoxifen remained unchanged. CONCLUSION: CBD at a low dose of 40 mg/day resulted in the potential inhibition of CYP3A4 and/or CYP2D6. Patients receiving CBD and interacting chemotherapeutic drugs, such as tamoxifen, require monitoring to identify possible subtherapeutic response to treatment. Further pharmacokinetic studies are required to ascertain the dynamics of this drug interaction.
