Adult Guidelines
Voriconazole Dosing Protocol

Voriconazole Dosing Protocol

Voriconazole Dosing at Mercy

Patients with a BMI ≥30 kg/m²: 

  • Voriconazole will be dosed based on adjusted body weight using the following equation:
    • Adjusted body weight = ideal body weight + ([actual body weight – ideal body weight]*0.4)

Order Verification Notes:

  • Select the “adjusted” weight button in order entry for patients with a BMI ≥30 kg/m²
  • Weight can be changed by a pharmacist during verification if the patient applies to this policy
  • If a provider wants to use total body weight in an obese patient, this must be specified as “DAW” in the admin instructions

Background

To use the most appropriate weight for voriconazole dosing in obese patients

  • Voriconazole dosing is weight based but current evidence does not support that clearance substantially increases with increasing body weight in obese patients (Eljaaly and Nix)
  • A retrospective study found higher IV mean trough concentrations and rates of supratherapeutic troughs in obese versus nonobese patients dosed on total body weight (6.2 vs 3.5 mg/L, p <0.0001, 67% vs 17%, p <0.0001, respectively) (Koselke et al.)
  • Another retrospective study found that IV voriconazole random levels were significantly higher in patients with a BMI 25 kg/m² or greater versus a BMI <25 kg/m² (6.4 vs 2.8 mg/L, p = 0.04) but no difference was found with oral voriconazole (Davies-Vorbrodt et al.)
  • Using total body weight in obese patients could lead to higher exposure and toxicity of voriconazole and the IV vehicle of cyclodextrin

Additional Information

  1. Eljaaly K and Nix DE. Voriconazole dosing in obese patients. Clin Infect Dis. 2016. 63: 286-7.
  2. Koselke E, Kraft S, Smith J, et al. Evaluation of the effect of obesity on voriconazole serum concentrations. J Antimicrob Chemother. 2012. 67: 2957-62.
  3. Davies-Vorbrodt S, Ito JI, Tegtmeier BR, et al. Voriconazole serum concentrations in obese and overweight immunocompromised patients: a retrospective review. Pharmacotherapy. 2014. 33: 22-30.