Hi all,
Seeking assistance for dose management of posaconazole levels for 21-year-old male patient with history of HIV, HTN, and ESRD on HD with diagnosis of invasive aspergillus. Pharmacogenomic testing revealed that patient is rapid metabolizer of CYP2C19 and therefore voriconazole is not recommended. Posaconazole prescribed with loading dose and then 300mg once daily. Subtherapeutic level returned, and dose increased to 200mg bid (see attached article for increased dosing reference). Seven days later with confirmed zero drug interactions, and 100% adherence posaconazole level is 0.3. It is my understanding that UGT1A1 primarily drives posaconazole metabolism, but could remnants of CYP metabolism still play into this subtherapeutic level? Recommend attempting to further increase dose and check level in 7 days being very mindful of toxicity/increased side effect potential? Anyone with successful isavuconazole experience in treating invasive aspergillus?
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[Susan ] [Carr]
[St. Jude Children's Research Hospital]
[Memphis] [TN]
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