Q&A: ‘A lot of opportunity’ exists to educate patients on hemodialysis about cannabis use
Key takeaways:
- More than 20% of patients on hemodialysis reported cannabis use, but only 8% had ever been asked about it.
- Cannabis does not interfere with dialysis but could interact with drugs used by this population.
Patients with kidney disease may be using cannabis recreationally or to treat symptoms without the knowledge of their health care team, according to results of a small survey of patients from a hemodialysis clinic in Canada.
Cannabis was legalized for medical and recreational use in Canada in 2018. In July and August 2020, Marisa Battistella, PharmD, a pharmacy clinician scientist specializing in chronic kidney disease at the University Health Network and the Leslie Dan Faculty of Pharmacy at the University of Toronto, and colleagues sought to characterize the attitudes and practices of patients on maintenance hemodialysis at their ambulatory clinic at Toronto General Hospital. Of the 52 survey respondents, 11 reported using cannabis in the preceding 3 months, and 23 reported ever using cannabis.

“In our study, we did not have a lot of people who responded that they were using cannabis, but that was probably underreported because of stigma. Mind you, our study was a survey 5 years ago, and it was during COVID. I think, anecdotally, over the last few years, more and more people are using it. We get asked by patients on rounds more often about what forms they can use and where they can buy it.”
Healio talked with Battistella about implications of the survey findings for kidney care.
Healio: Did you find any of your study results surprising?
Battistella: We had three big take-home messages: First, we found a high proportion of patients with self-directed cannabis use. Second, there is a huge role for pharmacists and for the health care team to proactively identify people using cannabis. And third, smoking cannabis was one of the most common routes, as it probably is, even outside of our dialysis population.
There is a lot of opportunity for our health care team to do harm reduction and patient education on, for example, more appropriate dosage forms if patients are going to use cannabis. Patients who use cannabis perceive it as effective and safe. So, maybe there is opportunity for us to educate patients, as well as the different staff, to take away some of that stigma and then help patients make better decisions if they are more educated.
To our surprise, when we interviewed or surveyed patients, only 8% reported ever being asked by the health care team or the hemodialysis team whether they were using cannabis. I feel like we ask more often, but maybe we just do not. We probably should ask more about it.
Healio: Does cannabis have any specific effects on the kidney?
Battistella: There are limited data on cannabis use in CKD and any potential harm in that population. But in terms of drug interactions, the THC and CBD components in cannabis do interact potentially with other drugs because cannabinoids inhibit the CYP 3A4 and CYP 2C9 enzymes [that metabolize drugs in the liver]. This is not well-documented, but there is potential for drug interactions.
We have to be mindful of interactions especially with some of the agents that go through that metabolism process, like warfarin, some of the selective serotonin reuptake inhibitors, like sertraline, and immunosuppressants in the transplant population.
So, for certain populations, patients should talk to their pharmacist, they might start low and monitor for adverse effects and potential drug interactions that would cause drowsiness, that sort of thing, but we do not think it interferes with dialysis. The literature is limited and focuses on the general population, but patients on dialysis do use cannabis, and we do not see worse adverse effects for them. We will never know unless we actually study it. As health care providers, we should always think about monitoring and looking for these potential adverse effects.
Healio: What conditions might someone with kidney disease use cannabis for?
Battistella: From what we see from our survey, they are using cannabis for chronic pain, nausea, vomiting, anorexia or lack of appetite, insomnia and pruritus. This is interesting because these symptoms are major concerns in our dialysis population.
Clinicians are starting to do more research with cannabis, for example, it is currently be studied to help with pruritus, or itch, with topical cannabis products, which are safe because they are not absorbed. We are worried less about drug interactions with topical products. When we can use dosages and forms that potentially can cause less adverse effects, that is a win-win for everybody.
Healio: What advice would you give to health care providers and patients?
Battistella: For health care providers, we should always be asking in a way that makes patients feel comfortable to report that they are using some type of cannabis product. We need a bit more education around that for health care providers, that they know how to ask and how to respond to patients’ reports and questions.
For patients on dialysis at our center, we wrote in our quarterly newsletter about what cannabis is and how it is being used. We advised them to always ask their health care provider if they have questions about using it. Patients are motivated to educate themselves on different medicines and health concerns. It is more an issue of we as health care providers making sure we understand we understand patients’ perspectives as well as making sure we ask about it.”
Reference:
Ho J, et al. Can J Kidney Health Dis. 2024;doi:10.1177/20543581241274002.
For more information:
Marisa Battistella, PharmD, is a pharmacy clinician scientist specializing in chronic kidney disease at the University Health Network and the Leslie Dan Faculty of Pharmacy at the University of Toronto in Canada. She can be reached at marisa.battistella@uhn.ca; X: @marisabatt100; LinkedIn: www.linkedin.com/in/marisa-battistella-1a3245a..