Medical Marijuana-Induced Tacrolimus Toxicity

Systematic review of drug-drug interactions of delta-9-tetrahydrocannabinol, cannabidiol, and Cannabis

Background

The recent exponential increase in legalized medical and recreational cannabis, development of medical cannabis programs, and production of unregulated over-the-counter products (e.g., cannabidiol (CBD) oil, and delta-8-tetrahydrocannabinol (delta-8-THC)), has the potential to create unintended health consequences. The major cannabinoids (delta-9-tetrahydrocannabinol and cannabidiol) are metabolized by the same cytochrome P450 (CYP) enzymes that metabolize most prescription medications and xenobiotics (CYP3A4, CYP2C9, CYP2C19). As a result, we predict that there will be instances of drug-drug interactions and the potential for adverse outcomes, especially for prescription medications with a narrow therapeutic index.

Methods

We conducted a systematic review of all years to 2023 to identify real world reports of documented cannabinoid interactions with prescription medications. We limited our search to a set list of medications with predicted narrow therapeutic indices that may produce unintended adverse drug reactions (ADRs). Our team screened 4,600 reports and selected 151 full-text articles to assess for inclusion and exclusion criteria.

Results

Our investigation revealed 31 reports for which cannabinoids altered pharmacokinetics and/or produced adverse events. These reports involved 16 different Narrow Therapeutic Index (NTI) medications, under six drug classes, 889 individual subjects and 603 cannabis/cannabinoid users. Interactions between cannabis/cannabinoids and warfarin, valproate, tacrolimus, and sirolimus were the most widely reported and may pose the greatest risk to patients. Common ADRs included bleeding risk, altered mental status, difficulty inducing anesthesia, and gastrointestinal distress. Additionally, we identified 18 instances (58%) in which clinicians uncovered an unexpected serum level of the prescribed drug. The quality of pharmacokinetic evidence for each report was assessed using an internally developed ten-point scale.

Conclusion

Drug-drug interactions with cannabinoids are likely amongst prescription medications that use common CYP450 systems. Our findings highlight the need for healthcare providers and patients/care-givers to openly communicate about cannabis/cannabinoid use to prevent unintended adverse events. To that end, we have developed a free online tool (www.CANN-DIR.psu.edu) to help identify potential cannabinoid drug-drug interactions with prescription medications.

Substance use disorders in organ transplantation: perennial challenges and interprofessional opportunities

PURPOSE OF REVIEW

The current article examines recent publications regarding ongoing clinical and ethical challenges and opportunities related to substance use disorders (SUD) in solid organ transplantation (SOT) utilizing a lens of interprofessional clinical models and care delivery.

RECENT FINDINGS

Innovative interprofessional clinician skillsets and care models are increasingly emphasized in the SOT literature as the standard of care for common, complex psychosocial problems like substance use and SUD. Cannabinoids are common among candidates and recipients and present several unique quandaries to SOT teams. Opioid use disorder treatment can often be definitively treated with medications that SOT teams may find unfamiliar, controversial, or aversive. Arguably the quintessential example of SUD in SOT, early liver transplantation for patients with alcohol-related liver disease and short periods of sobriety has become increasingly common and accepted in recent years requiring liver teams to rapidly acquire significant interprofessional psychiatric awareness and expertise. The question of retransplantation in patients who have experienced recurrent SUD remains unsettled.

SUMMARY

Regardless of substances used or organs transplanted, interprofessional care continues to emerge as a foundational aspect of clinical care and research in SOT.

Cannabinoids and solid organ transplantation: Psychiatric perspectives and recommendations

Cannabinoid use in patients seeking solid organ transplantation (SOT) is an important and unsettled matter which all transplantation clinicians regularly encounter. It is also a multifaceted, interprofessional issue, difficult for any specialty alone to adequately address in a research article or during clinical care. Such uncertainty lends itself to bias for or against cannabinoid use accompanied by inconsistent policies and procedures. Scientific literature in SOT regarding cannabinoids often narrowly examines the issue and exists mostly in liver and kidney transplantation. Published recommendations from professional societies are mosaics of vagueness and specificity mirroring the ongoing dilemma. The cannabinoid information SOT clinicians need for clinical care may require data and perspectives from diverse medical literature which are rarely synthesized. SOT teams may not be adequately staffed or trained to address various neuropsychiatric cannabinoid effects and risks in patients. In this article, authors from US transplantation centers conduct a systematized review of the few existing studies regarding clinician perceptions, use rates, and clinical impact of cannabinoid use in SOT patients; collate representative professional society guidance on the topic; draw from diverse medical literature bases to detail facets of cannabinoid use in psychiatry and addiction pertinent to all transplantation clinicians; provide basic clinical and policy recommendations; and indicate areas of future study.

Therapeutic Cannabis Use in Kidney Disease: A Survey of Canadian Nephrologists

Rationale & Objective

Cannabis use may be helpful for symptom management in patients with chronic kidney disease (CKD). Knowledge, attitudes, and comfort with use of medical cannabis among kidney care providers may be limiting more widespread evaluation and use. We surveyed Canadian nephrologists regarding current prescribing habits, attitudes, and overall comfort level with cannabis products.

Study Design

We carried out a nationwide, mail-in survey focused on capturing general and practice demographics, current cannabis prescribing status, and knowledge and attitudes regarding therapeutic cannabis use in patients with CKD.

Setting & Population

This survey was distributed to every registered nephrologist in Canada.

Analytical Approach

The results of this survey are reported descriptively.

Results

Responses were received from 208 of 723 (29%) nephrologists. Only 21 (10.1%) respondents currently prescribe cannabis, with chronic pain syndromes being the most frequent reason for cannabis prescription (95.2%). Overall, 116 (55.5%) participants reported that changes in legality of cannabis did not influence their decision to prescribe cannabis. The majority of respondents (n = 123; 59%) indicated that they were uncomfortable with their knowledge of the medical cannabis literature. Most respondents (n=188; 91%) indicated that further studies exploring the efficacy and safety of cannabis would likely influence their prescribing habits.

Limitations

Limitations of this study include possible nonresponse bias and a lack of specific data on practice considerations for specific subpopulations, such as transplant patients.

Conclusions

Only a small minority of Canadian nephrologists currently prescribe cannabis, with relatively little practice change after legalization. There is broad support amongst Canadian nephrologists for encouraging their patients to enroll in efficacy/safety studies of cannabis in the CKD population. Ultimately, given limited therapeutic options available for symptom control in CKD, this survey demonstrates the potential for nationwide practice change if cannabis efficacy and safety can be demonstrated in this population.

Late presentation of posterior reversible encephalopathy syndrome following liver transplantation in the setting of tacrolimus and cannabis use

A 45-year-old female presented to hospital with confusion and visual disturbances. She had undergone a liver transplant 3 years prior for cirrhosis secondary to primary biliary cholangitis. Computed tomography and magnetic resonance imaging of the brain showed features consistent with posterior reversible encephalopathy syndrome. Her medications included tacrolimus, sirolimus, and prednisone. She reported smoking 4 grams of cannabis per day. Following cessation of tacrolimus, the patient's encephalopathy and visual disturbances resolved. To our knowledge, this case represents the longest time elapsed from liver transplantation to the development of tacrolimus-associated posterior reversible encephalopathy syndrome in the literature. This case highlights the potential danger of cannabis use in transplant recipients who are on immunosuppressants such as tacrolimus. Clinicians should have a high index of suspicion for posterior reversible encephalopathy syndrome in post-transplant patients presenting with altered mental status, even years after liver transplantation, and be familiar with potential interactions between cannabis and immunosuppressants.

Cannabinoid Use Among Liver Transplant Recipients

The effect of cannabinoids on liver transplant outcomes is an area of active research. We aimed to investigate marijuana (MJ) and cannabidiol (CBD) use among liver transplant recipients at the University of Colorado Hospital (UCH), specifically prevalence, habits, and predictors of use. Liver transplant recipients followed at UCH with valid email addresses were sent an informed consent postcard and survey invitation. This exploratory survey was conducted using REDCap. IBM SPSS Statistics software was used for statistical analysis. Of 1227 recipients who were sent surveys, 538 people responded. On average, respondents were 59 years old, with 63.7% male and 81.7% White. Hepatitis C virus (HCV; 30.4%) and alcohol use (17.7%) were the most common etiologies of liver disease. Among respondents, 23.8% reported current MJ use. Methods of use included smoking (72.4%), ingestion (55.3%), and vaporization (31.7%). Top reasons for MJ use were recreation (56.5%), anxiety (54.8%), and pain (53.2%). Among respondents, 21.0% currently used CBD, usually in the form of creams or lotions (58.9%) and to relieve pain (84.9%) and anxiety (31.1%). In multivariable analysis, age (odds ratio [OR], 0.941; 95% confidence interval [CI], 0.923-0.959; P < 0.001), diabetes mellitus (OR, 0.357; 95% CI, 0.171-0.746; P = 0.01), HCV cirrhosis (OR, 3.949; 95% CI, 2.281-6.835; P < 0.001), alcohol-related cirrhosis (OR, 2.101; 95% CI, 1.202-3.671; P = 0.01), and current tobacco use (OR, 2.918; 95% CI, 1.065-7.990; P = 0.04) were significant predictors of MJ use. Our study shows that cannabinoid use after liver transplant is common. MJ use is associated with decreasing age, alcohol-related and HCV cirrhosis, and tobacco use. Anxiety, pain, and recreation were top reasons for its use. Transplant teams should address reasons why their patients use MJ and CBD and develop programs to mitigate anxiety and pain after transplant. Further studies are needed to examine effects of cannabinoids on liver transplant outcomes.

Marijuana use among adult liver transplant candidates and recipients

BACKGROUND

Data regarding marijuana (MJ) use among liver transplant (LT) candidates are limited. We set out to determine the incidence and pre- and post-LT outcomes of adult LT candidates with a self-reported history of MJ use.

METHODS

Baseline clinical characteristics, waitlist, and post-LT outcomes of adult LT candidates from January 2010 to March 2017 were compared.

RESULTS

Among 2690 LT candidates, 630(23%) and 298(11%) reported a history of MJ use and use within the past 12 months, respectively. Although the proportion of MJ users increased over time(β = .76, p = .03), the proportion listed and transplanted did not change. Listing for LT increased with male (OR 1.24, 95% CI 11.01-1.52), MELD score (OR 1.08, 95% CI 1.01-1.15), HCC (OR 1.83, 95% CI 1.39-2.41) but decreased among MJ users (OR 0.67, 95% CI 0.50-0.91, p = .01). The median time to listing was longer among MJ users compared to non-users (115 vs. 87 days, p < .0005). Post-LT survival was similar in 83 MJ users and 306 non-users.

CONCLUSION

The proportion of MJ users among LT candidates is increasing. MJ users have a greater burden of psychosocial issues which may contribute to longer evaluations and lower rate of LT listing. Post-LT survival was not impacted by self-reported MJ use history.

The nephrologist's guide to cannabis and cannabinoids

PURPOSE OF REVIEW

Cannabis (marijuana, weed, pot, ganja, Mary Jane) is the most commonly used federally illicit drug in the United States. The present review provides an overview of cannabis and cannabinoids with relevance to the practice of nephrology so that clinicians can best take care of patients.

RECENT FINDINGS

Cannabis may have medicinal benefits for treating symptoms of advanced chronic kidney disease (CKD) and end-stage renal disease including as a pain adjuvant potentially reducing the need for opioids. Cannabis does not seem to affect kidney function in healthy individuals. However, renal function should be closely monitored in those with CKD, the lowest effective dose should be used, and smoking should be avoided. Cannabis use may delay transplant candidate listing or contribute to ineligibility. Cannabidiol (CBD) has recently exploded in popularity. Although generally well tolerated, safe without significant side effects, and effective for a variety of neurological and psychiatric conditions, consumers have easy access to a wide range of unregulated CBD products, some with inaccurate labeling and false health claims. Importantly, CBD may raise tacrolimus levels.

SUMMARY

Patients and healthcare professionals have little guidance or evidence regarding the impact of cannabis use on people with kidney disease. This knowledge gap will remain as long as federal regulations remain prohibitively restrictive towards prospective research.