Noxafil (Posaconazole)

Noxafil (posaconazole) is used to manage invasive fungal infections and to prevent opportunistic fungal disease in high‑risk patients.

• Invasive aspergillosis: treatment of proven or probable infection in patients with hematologic malignancies or stem‑cell transplants.
• Invasive candidiasis: treatment of candidemia and other forms of invasive candidiasis in adults.
• Prophylaxis of fungal infections: prevention of aspergillosis and candidiasis in immunocompromised individuals receiving chemotherapy or prolonged corticosteroids.

• Posaconazole inhibits the fungal enzyme lanosterol 14α‑demethylase, a key cytochrome P450 isoform. By blocking this step, it prevents conversion of lanosterol to ergosterol, leading to depletion of ergosterol in the cell membrane and accumulation of toxic sterol intermediates, which disrupts membrane integrity and halts fungal growth.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Diarrhea: loose stools that may be watery.
• Headache: transient cranial discomfort.
• Elevated liver enzymes: increase in ALT/AST levels.

Serious or Rare Side Effects

• Hepatotoxicity: severe liver injury requiring monitoring.
• QT interval prolongation: risk of cardiac arrhythmias.
• Severe hypersensitivity reactions: including anaphylaxis.
• Stevens‑Johnson syndrome or toxic epidermal necrolysis: rare skin eruptions.
• Visual disturbances: blurred vision or photophobia.
• Severe hypertension: marked increase in blood pressure.

Precautions for Noxafil include careful assessment before initiating therapy.

• Pregnancy Category C: use only if potential benefit justifies potential risk.
• Liver function monitoring: check ALT/AST before and during treatment.
• QT interval monitoring: avoid in patients with known prolongation or concurrent QT‑prolonging drugs.
• Drug‑interaction awareness: review concomitant CYP3A4 substrates, inhibitors, and inducers.
• Store at ambient temperature: keep below 25°C, protect from moisture and store in original packaging.

Posaconazole has several clinically relevant drug interactions.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin): may increase posaconazole exposure.
• Drugs that prolong QT interval (e.g., quinidine, sotalol, amiodarone): heightened risk of arrhythmia.
• HIV protease inhibitors (e.g., ritonavir): can raise plasma concentrations.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin): may reduce efficacy.
• Statins metabolized by CYP3A4 (e.g., simvastatin, lovastatin): increased risk of myopathy.
• Oral contraceptives: reduced hormonal effectiveness, consider alternative contraception.