MTM Specialty Medication Management 4 — Questions and Answers
Question 1: A patient on cyclosporine for organ transplant is prescribed fluconazole for a vaginal yeast infection. What is the MTM pharmacist's BEST action?
- Approve the combination without concerns
- Alert the prescriber: fluconazole inhibits CYP3A4 and can cause significant cyclosporine toxicity; suggest topical antifungal instead (Correct answer)
- Advise patient to stop cyclosporine temporarily
- Recommend reducing cyclosporine dose by half without contacting prescriber
Correct answer: Alert the prescriber: fluconazole inhibits CYP3A4 and can cause significant cyclosporine toxicity; suggest topical antifungal instead
Fluconazole strongly inhibits CYP3A4, significantly increasing cyclosporine levels and risk of nephrotoxicity; a topical antifungal is safer.
Question 2: Which specialty medication for hepatitis C requires genotype testing before prescribing to confirm efficacy?
- Ribavirin
- Sofosbuvir/velpatasvir (Epclusa) — which covers all genotypes
- Elbasvir/grazoprevir (Zepatier) — effective for genotypes 1 and 4 only (Correct answer)
- Ledipasvir/sofosbuvir (Harvoni) — effective for genotypes 1, 4, 5, 6
Correct answer: Elbasvir/grazoprevir (Zepatier) — effective for genotypes 1 and 4 only
Elbasvir/grazoprevir is indicated only for HCV genotypes 1 and 4, making genotype testing essential before prescribing.
Question 3: A pharmacist identifies that a patient on mycophenolate mofetil (CellCept) has been started on cholestyramine. What is the clinical concern?
- Cholestyramine increases mycophenolate bioavailability
- Cholestyramine binds to mycophenolic acid in the gut, reducing its absorption and potentially leading to transplant rejection (Correct answer)
- Cholestyramine causes additive immunosuppression
- There is no clinically significant interaction
Correct answer: Cholestyramine binds to mycophenolic acid in the gut, reducing its absorption and potentially leading to transplant rejection
Cholestyramine interrupts enterohepatic recirculation of mycophenolic acid, significantly reducing drug exposure and risking organ rejection.
Question 4: A patient on vedolizumab (Entyvio) for Crohn's disease asks if they can receive live vaccines. What is the appropriate counseling?
- Live vaccines are safe because vedolizumab acts only in the gut
- Live vaccines are contraindicated; inactivated vaccines are preferred (Correct answer)
- Vaccines should be avoided entirely during therapy
- Live vaccines are safe if given at least 1 week before infusion
Correct answer: Live vaccines are contraindicated; inactivated vaccines are preferred
Although vedolizumab is gut-selective, live vaccines are contraindicated in immunocompromised patients on biologics due to risk of vaccine-induced infection.
Question 5: During MTM, a patient on enzalutamide (Xtandi) for prostate cancer is noted to be on warfarin. What is the major drug interaction?
- Enzalutamide inhibits CYP2C9, markedly increasing warfarin levels
- Enzalutamide induces CYP3A4 and CYP2C9, reducing warfarin exposure and INR (Correct answer)
- Enzalutamide has no effect on warfarin metabolism
- Enzalutamide displaces warfarin from albumin binding sites
Correct answer: Enzalutamide induces CYP3A4 and CYP2C9, reducing warfarin exposure and INR
Enzalutamide is a potent CYP3A4 and CYP2C9 inducer, significantly reducing warfarin levels and requiring close INR monitoring with possible dose increases.
Question 6: A patient on ustekinumab (Stelara) for psoriasis develops signs of bacterial pneumonia. What key drug safety consideration applies?
- Ustekinumab must be permanently discontinued if any infection occurs
- Ustekinumab should be withheld during active serious infection and restarted only after resolution (Correct answer)
- Ustekinumab can be continued with concurrent antibiotics without concerns
- Ustekinumab dose should be doubled to boost immune response
Correct answer: Ustekinumab should be withheld during active serious infection and restarted only after resolution
Biologic therapy including ustekinumab should be withheld during active serious infections and resumed only after clinical resolution to minimize infection risk.
Question 7: Which specialty medication for pulmonary arterial hypertension (PAH) requires a mandatory REMS program due to teratogenicity?
- Sildenafil (Revatio)
- Bosentan (Tracleer) via the Tracleer REMS program
- Treprostinil (Remodulin)
- Ambrisentan (Letairis) via the Letairis REMS program (Correct answer)
Correct answer: Ambrisentan (Letairis) via the Letairis REMS program
Ambrisentan carries a black box warning for teratogenicity and is available only through the Letairis REMS program requiring monthly pregnancy tests.
MTM Specialty Medication Management 4
A patient on cyclosporine for organ transplant is prescribed fluconazole for a vaginal yeast infection.
What is the MTM pharmacist's BEST action?