Prospective Evaluation of Adjusted Body Weight Dosing of Acyclovir in Obesity

West Virginia University13 enrolled

Overview

Patients receiving acyclovir as standard of care will be enrolled into this study. The currently recommended dosing strategy at our institution for obese patients is to receive intravenous acyclovir dosed per an adjusted body weight \[IBW + 0.4(TBW-IBW)\]. They will have blood drawn once prior to the first dose of acyclovir and 10 times thereafter, over a total time period of 12 hours. These patients will already be hospitalized for other reasons, and will not be required to make additional trips to the hospital. A total of approximately 4-5 tablespoons of blood will be drawn for this study. Ten obese patients and 10 matched control (non-obese) patients will be enrolled.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Obesity

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age ≥18 years of age * Receiving intravenous acyclovir 5 mg/kg (TBW for normal weight patients and ABW40 for obese patients) as part of their routine care * Weight \> 190% of ideal body weight (IBW) for "obese" patients or weight 80-120% of IBW for matched control patients. Exclusion Criteria: * Receipt of acyclovir or a pro-drug of acyclovir (valacyclovir, ganciclovir, valganciclovir, famciclovir) in the prior 24 hours * Serum creatinine \>1.5 mg/dL * Hypersensitivity to acyclovir * Patients requiring ventilator support or vasopressors in the prior 24 hours * Receipt of probenecid, mycophenolate, tenofovir, or zidovudine in the prior 7 days * Significant anatomical deformities that influence body habitus (i.e. amputation) * Prior inclusion in this study

Locations (1)

Outcomes

Primary Outcomes

Area under the curve (AUC) of systemic acyclovir exposure in obese and non-obese patients

Time frame: 12 hours

Secondary Outcomes

Half-life of acyclovir in obese and non-obese patients

Time frame: 12 hours

Maximum concentration (Cmax) of acyclovir in obese and non-obese patients

Time frame: 12 hours

Time to maximum concentration (Tmax) of acyclovir in obese and non-obese patients

Time frame: 12 hours

Volume of distribution (Vd) of acyclovir in obese and non-obese patients

Time frame: 12 hours

Systemic Clearance of acyclovir in obese and non-obese patients

Time frame: 12 hours

Time that concentration is above IC50 for varicella and herpes viruses in obese and non-obese patients

Time frame: 12 hours