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posaconazole (Noxafil)

Indications: - prevention of invasive fungal infections in immunocompromised hosts (>= 13 years of age) - aspergillosis - Candida infections Contraindications: - concurrent use of ergot alkaloids, pimozide, cisapride, quinidine Pregnancy category: C Dosage: - 200 mg (one teaspoon) TID - delayed release tablet also available 40 mg/mL oral suspension, 4-ounces * oral suspension & delayed release dosing not the same dosage adjustment rqwuired [5] Pharmacokinetics: 1) food increases absorption 2) metabolized by glucuronidation 3) posaconazole inhibits CYP3A4 Monitor: - liver function test baseline & during treatment [3] Adverse effects: 1) nausea/vomiting (30-38%) 2) headache (28%) 3) abnormal liver function tests, hepatitis (uncommon) Drug interactions: 1) rifabutin & phenytoin can diminish posaconazole levels via enzyme induction 2) cimetidine can diminish posaconazole absorption by increasing gastric pH - other H2 blockers & proton pump inhibitors do not seem to interact 3) posaconazole inhibits CYP3A4 substrates thus may increase levels of pharmaceuticals metabolized by CYP3A4 a) diminish dose of tacrolimus 66% & monitor trough b) diminish dose of cyclosporine 25% & monitor trough 4) monitor WBC & for uveitis when used with rifabutin 5) phenytoin levels should be monitored with concomitant use 6) monitor for hypoglycemia when used with glipizide 7) NO interaction with zidovudine, lamivudine, ritonavir, indinavir Laboratory: - posaconazole in hair - posaconazole in serum/plasma Mechanism of action: 1) inhibits synthesis of ergosterol 2) inhibits lanosterol 14-alpha-demethylase

Interactions

drug interactions

General

antifungal agent triazole; pyrrodiazole

Properties

MISC-INFO: elimination route LIVER 1/2life >40 HOURS therapeutic-range >1 UG/ML pregnancy-category C

Database Correlations

PUBCHEM correlations

References

  1. Prescriber's Letter 13(11): 2006 New Drug: Noxafil (Posaconazole) Detail-Document#: 221106 (subscription needed) http://www.prescribersletter.com
  2. Schering Corporation Kenilworth, NJ 07033 908-298-4000 http://www.schering-plough.com
  3. Prescriber's Letter 17(7): 2010 Recommended Lab Monitoring for Common Medications Liver Function Test Scheduling Detail-Document#: 260704 (subscription needed) http://www.prescribersletter.com
  4. Deprecated Reference
  5. FDA safety alert. 01/04/2016 Noxafil (posaconazole): Drug Safety Communication - Dosing Errors when Switching between Different Oral Formulations; Label Changes Approved. http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm479782.htm