USP Results In
A Case Study Challenge

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U.S. Pharmacist
Case Study
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selected feedback
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What Would You Do?

Voriconazole Pharmacokinetics in a
3-Year-Old Male With ALL

Click here for this case study, which was
emailed to you on April 12, 2012.

Author Answer

The patient was continued on voriconazole and the dose was increased to 11 mg/kg over the course of several days. Voriconazole demonstrates nonlinear pharmacokinetics in adults and linear pharmacokinetics in children, as well as variable absorption and distribution in the pediatric population depending on the child’s age. Monitoring voriconazole is essential if the patient is not responding to therapy or if the patient demonstrates signs of toxicity. Levels less than or equal to 1 mcg/mL are associated with lack of response to therapy, whereas levels greater than or equal to 5.5 mcg/mL are associated with toxicity. Variability in oral bioavailability associated with meals and hepatic first-pass effect may contribute to lower exposure to voriconazole. Voriconazole has been shown to be less bioavailable in the younger child (2-6 years old) compared with the older child (6-12 years) and adults (>12 years).

Literature suggests that voriconazole 10 to 11 mg/kg in pediatric patients demonstrates similar AUC as 4 mg/kg in adults; however, the author cautions that at these doses, it is unknown whether the pharmacokinetics would remain linear. The duration of therapy of voriconazole for this indication depends on clinical response. Long-term suppressive therapy is indicated for patients on immunosuppressive therapy.

Close monitoring of voriconazole efficacy and toxicity is warranted, especially if the clinical picture of the patient changes. The patient’s condition was stable upon discharge. His hepatic function was stable, and he did not exhibit any signs of toxicity or exacerbation of his fungal infection.

Mary Soliman, PharmD
PGY-2 Pediatric Pharmacy Resident
St Joseph's Children's Hospital, Tampa, Florida

Kimberly Perez, PharmD
Pediatric Hematology/Oncology Clinical Pharmacist
St Joseph's Children's Hospital, Tampa, Florida

Reader Response

I would look into each of the chemo agents, remove the one causing the most trouble, and get the voriconazole level to therapeutic levels.

J. Ulrich, RPh
United Regional
Wichita Falls, Texas

Reader Response

I would recommend amphotericin B 5 mg/k daily. Would be nice to know specie of fusarium. Ampho B may afford less drug-drug interaction. 

E. Wattigny
Helena Regional Medical Center
Helena, Arkansas