Home Drug Guide Posaconazole

Drug Guide

Generic Name

Posaconazole

Brand Names Noxafil, Noxafil Powdermix Kit

Classification

Therapeutic: Antifungal

Pharmacological: Azole antifungal

FDA Approved Indications

  • Prophylaxis of invasive Aspergillus and Candida infections in immunocompromised patients at high risk
  • Treatment of oropharyngeal candidiasis in patients who are refractory or intolerant to conventional therapy

Mechanism of Action

Posaconazole inhibits fungal cytochrome P450 enzyme 14α-sterol demethylase, leading to decreased ergosterol synthesis and increased membrane permeability, which inhibits fungal growth.

Dosage and Administration

Adult: Varies by formulation and indication; typical dose for prophylaxis is 300 mg twice on day 1, then 300 mg once daily; for oral suspension, taken with food.

Pediatric: Safety and efficacy established for pediatric patients 13 years and older; dosing tailored to body weight and specific indication.

Geriatric: Use with caution; no specific dosage adjustment required but monitor for adverse effects.

Renal Impairment: No dose adjustment necessary, but caution advised; monitor renal function.

Hepatic Impairment: Use with caution; dosing adjustments may be necessary; monitor liver function.

Pharmacokinetics

Absorption: Poorly absorbed in fasting state; absorption significantly increased when taken with a high-fat, high-calorie meal.

Distribution: Wide distribution; high plasma protein binding (~98%).

Metabolism: Metabolized mainly by UDP-glucuronidation and also by CYP3A4.

Excretion: Primarily via feces; minor renal excretion.

Half Life: Approximately 25-31 hours in healthy volunteers.

Contraindications

  • Hypersensitivity to posaconazole or other azole antifungals.

Precautions

  • Liver function impairment; drug interactions via CYP3A4 inhibitors or inducers; QT prolongation risk; cautions in pregnancy and breastfeeding.

Adverse Reactions - Common

  • Nausea (Common)
  • Vomiting (Common)
  • Headache (Common)
  • Fever (Common)

Adverse Reactions - Serious

  • QT prolongation and serious cardiac arrhythmias (Rare)
  • Liver enzyme elevations and hepatitis (Rare)
  • SHS (Severe hypersensitivity reactions) (Rare)

Drug-Drug Interactions

  • CYP3A4 inhibitors and inducers (e.g., ritonavir, ketoconazole, rifampin)
  • Other QT prolonging agents

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor liver function tests, renal function, and signs of adverse reactions.

Diagnoses:

  • Risk for infection due to immunosuppression
  • Potential for drug interactions

Implementation: Administer with food to enhance absorption; monitor for signs of hepatotoxicity and drug interactions.

Evaluation: Evaluate patient's response; monitor for adverse effects, especially liver function and cardiac status.

Patient/Family Teaching

  • Take medication with food to improve absorption.
  • Report signs of liver problems (jaundice, dark urine).
  • Inform about potential cardiac side effects and to report palpitations or dizziness.
  • Adhere strictly to dosing schedule.

Special Considerations

Black Box Warnings:

  • QT prolongation and serious cardiac arrhythmias,

Genetic Factors: Consider CYP3A4 genetic polymorphisms affecting metabolism.

Lab Test Interference: May elevate serum lipids and liver enzymes.

Overdose Management

Signs/Symptoms: Nausea, vomiting, dizziness, abnormal heart rhythms.

Treatment: Supportive care; activated charcoal may be considered within 1 hour of ingestion; no specific antidote.

Storage and Handling

Storage: Store at room temperature, away from moisture and heat.

Stability: Warms to room temperature; unopened vials and powder mix kits stable as per package insert.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.