May 2021 Imaging Case of the Month: A Growing Indeterminate Solitary Nodule

No abstract available. Article truncated after 150 words. A 58-year-old woman with a history of orthotopic heart transplant, performed for Adriamycin-induced cardiomyopathy, treated with mycophenolate and tacrolimus, presented for routine interval follow up. The patient’s past medical history was significant for follicular thyroid carcinoma treated with total thyroidectomy and bilateral breast carcinoma in remission as well as hypothyroidism and type II diabetes mellitus. In addition to tacrolimus and mycophenolate, the patient’s medications included aspirin, insulin, itraconazole (for anti-fungal prophylaxis), levothyroxine, prednisone (tapering since transplant), and valganciclovir. The patient recently complained of rhinorrhea and cough productive of brown-tinged sputum, improving over the previous 2 weeks; she denied fever, chills, shortness of breath, night sweats chest pain, or gastrointestinal symptoms. Physical examination showed the patient to be afebrile with normal heart and respiratory rates and blood pressure. Her room air oxygen saturation was 99%. The patient’s complete blood count and serum chemistries showed largely normal values, with the white blood …

Reduction in Tamoxifen Metabolites Endoxifen and N-desmethyltamoxifen With Chronic Administration of Low Dose Cannabidiol: A CYP3A4 and CYP2D6 Drug Interaction

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.