NAPLEX Question of the Week: Immunosuppressants

We head into Christmas break with a doozy!
NAPLEX Question of the Week: Immunosuppressants

PD is a 39 yo female who presents to your outpatient clinic for management of her maintenance immunosuppression medications. She received a kidney transplant about 2 weeks ago and was started on the anti-rejection regimen listed below. 

PMH: ESRD (now s/p kidney transplant), T2DM, HTN, Atrial fibrillation  

Allergies: codeine 

Medication List: 

Prograf 6 mg PO Q12H  

Cellcept 1000 mg PO Q12H 

Prednisone 5 mg PO QD 

Valcyte 900 mg PO QD x12 months  

Bactrim single-strength (400mg/80mg) PO QD x 6 months  

What are some important counseling points to provide to PD about her medications? Select all that apply. 

a)    None of these medications will require therapeutic drug monitoring 

b)    Prograf can cause hirsutism and hypotension  

c)    Prograf has potential drug interactions with CYP3A4 inducers and inhibitors 

d)    This patient can safely receive the Varicella vaccine if indicated  

e)    Cellcept is the immunosuppressant of choice in pregnancy  

f)     Valcyte is being used for CMV infection prophylaxis  

Brand/Generic: Prograf (tacrolimus), Cellcept (mycophenolate mofetil), Bactrim (Trimethoprim-sulfamethoxazole/TMP-SMX), Valcyte (valganciclovir)  

Rationale with Answers

Correct answers: C and F

Answer Choice A: False, tacrolimus is monitored based on steady state trough levels. Trough goals vary widely based on a variety of factors (type of transplant, drug formulation, other drugs in the regimen, etc). Typically, the trough goal is ~5-20 ng/mL depending on time from transplant. Trough levels are measured 30 minutes to 1 hour before the AM dose. It is important to tell patients to hold their morning dose until after blood work is drawn when they are coming in for monitoring. It is also important to make patients aware that their dose may be frequently changed and adjusted based on the trough levels, especially during the first year post transplant.  

Answer Choice B: False, tacrolimus can lead to hypertension and alopecia. Cyclosporine (another commonly used calcineurin inhibitor to prevent rejection) can cause hirsutism. Other side effects of tacrolimus to monitor for include: nephrotoxicity, neurotoxicity, electrolyte abnormalities (hyperkalemia, hypomagnesemia, hypophosphatemia), post-transplant diabetes, and headaches/tremor.  

Answer Choice C: True, tacrolimus has many potential drug interactions. CYP3A4 inducers (phenytoin, rifampin, carbamazepine, etc) will potentially decrease tacrolimus levels, and 3A4 inhibitors (azole antifungals, diltiazem, verapamil, ritonavir, grapefruit juice) will potentially increase tacrolimus levels. These interactions can potentially lead to increased toxicity (inhibitors) or reduced efficacy (inducers), therefore it is very important to counsel patients on speaking with their providers before starting any new medication or supplement. 

Answer Choice D: False, severe complications have occurred in immunocompromised patients receiving live, attenuated viral, and live, attenuated bacterial vaccines. Patients receiving immunosuppressive therapy for solid organ transplant rejection prevention should not receive MMR, varicella, yellow fever, and nasal flu vaccines. If unsure, it is important to always check whether a vaccine is live before administration to these patients.  

Answer Choice E: False, Cellcept is a teratogen. It is very important to counsel women of child-bearing age about the teratogenicity of this drug. Other side effects of this drug include GI disturbances, leukopenia, anemia and thrombocytopenia.  

Answer Choice F: True, solid organ transplant recipients will typically receive infection prophylaxis for 3-12 months post-transplant and may be restarted after treatment for acute cellular rejection. Immunosuppression therapy puts these patients at increased risk of infection, and they may need bacterial, viral, and fungal coverage. Viral targets include cytomegalovirus (CMV), herpes virus (HSV) and zoster (VZV). CMV risk is categorized by donor and recipient history of CMV exposure. Bacterial targets typically include pneumocystis jirovecii pneumonia (PJP), urinary tract infections, and toxoplasmosis (heart transplants). Fungal targets are typically oral/esophageal thrush and fungal pneumonia. Valganciclovir covers CMV and Bactrim is a great choice for PJP prophylaxis.  

*Study Tip: For multiple select questions try to look at each statement as a true or false question to help narrow down answers! 

Exam Competencies: Area 1 – Obtain, Interpret, or Assess Data, Medical, or Patient Information (1.5 – Signs or symptoms of medical conditions, healthy physiology, etiology of diseases, or pathophysiology, 1.6 – Risk factors or maintenance of health and wellness), Area 2 – Identify Drug Characteristics (2.1 – Pharmacology, mechanism of action, or therapeutic class, 2.4 – Pregnancy or lactation), Area 3 – Develop or Manage Treatment Plans (3.4 – Drug dosing or dosing adjustments; duration of therapy, 3.6 – Drug contraindications, allergies, or precautions, 3.9 – Therapeutic monitoring parameters, monitoring techniques, monitoring tools, or monitoring frequency 3.10 – Drug pharmacokinetics or pharmacodynamics) 

This will be our last question for 2022. We will return strong in January 2023 with two straight columns on how to prepare well for the stretch run for the NAPLEX.

Have a wonderful Christmas and Happy New Year!


Dr. B

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