What is the recommended dose of Voriconazole (antifungal medication) for a 70 kg male?

Voriconazole Dosing for a 70 kg Male

For a 70 kg male, the recommended voriconazole dosing regimen is a loading dose of 400 mg (6 mg/kg) twice daily for 2 doses on day 1, followed by a maintenance dose of 200-300 mg (3-4 mg/kg) twice daily. 1, 2

Intravenous Administration

• Loading dose: 6 mg/kg every 12 hours for the first 24 hours (420 mg IV every 12 hours for a 70 kg patient) 1, 2
• Maintenance dose: 3-4 mg/kg every 12 hours (210-280 mg IV every 12 hours for a 70 kg patient) 1, 2

Oral Administration

• Loading dose: 400 mg (6 mg/kg) twice daily for 2 doses 1, 2
• Maintenance dose: 200-300 mg (3-4 mg/kg) twice daily 1, 2
• Oral bioavailability is excellent (>90%) and allows for easy transition between IV and oral formulations 1, 3

Dosing Considerations

Route of Administration

• Oral voriconazole should be administered at least one hour before or after a meal 2
• Food decreases the absorption of oral voriconazole 1, 3

Renal Function

• Intravenous voriconazole is not recommended for patients with creatinine clearance <50 mL/minute due to potential cyclodextrin accumulation 1
• Oral voriconazole does not require dosage adjustment for renal insufficiency 1

Hepatic Function

• Voriconazole is the only triazole that requires dosage reduction for patients with mild to moderate hepatic impairment 1, 4
• For patients with liver dysfunction, dosage adjustments based on total bilirubin levels are recommended 4

Drug Interactions

• Common polymorphisms in metabolic enzymes result in wide variability of serum levels 1
• Drug-drug interactions are common with voriconazole and should be carefully considered 1, 5
• Dose adjustments may be necessary when voriconazole is co-administered with certain medications (e.g., efavirenz) 5

Therapeutic Considerations

Indications

• Voriconazole is effective for both mucosal and invasive candidiasis 1
• It is particularly useful for step-down oral therapy in patients with infections due to C. krusei and fluconazole-resistant, voriconazole-susceptible C. glabrata 1
• Voriconazole achieves good CSF and vitreous concentrations (>50% of serum concentration) 1

Monitoring

• Due to nonlinear pharmacokinetics and variable metabolism, therapeutic drug monitoring may be beneficial 3, 6
• Common side effects include hepatic injury, visual side effects, photosensitivity, periostitis, and CNS side effects 1

Duration of Therapy

• For candidemia without obvious metastatic complications, treat for 2 weeks after documented clearance of Candida from the bloodstream and resolution of symptoms 1
• For invasive aspergillosis, the median duration in clinical trials was 10 days IV followed by 76 days oral therapy 1

Special Considerations

• Voriconazole should not be used for urinary candidiasis as it does not accumulate in active form in the urine 1
• For CNS aspergillosis, voriconazole is the primary recommended agent 1
• Crushed tablets are bioequivalent to whole tablets if needed for patients who cannot swallow whole tablets 7