Prospective Evaluation of Adjusted Body Weight Dosing of Acyclovir in Obesity

Study Overview
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Brief Summary
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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.

Official Title
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Prospective Evaluation of Adjusted Body Weight Dosing of Acyclovir in Obesity

Conditions
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Obesity

Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Obese Patients<br>Obese patients (patients whose weight is >190% of ideal body weight) will be receive a single dose of I.V. acyclovir sodium 5mg/kg dosed by adjusted body weight as part of their routine care. | |
| Non-obese Patients<br>Normal weigh patients (patients whose weight is 80-120% of ideal body weight) will be receive a single dose of I.V. acyclovir sodium 5mg/kg dosed by total body weight as part of their routine care. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Area under the curve (AUC) of systemic acyclovir exposure in obese and non-obese patients |  | 12 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Half-life of acyclovir in obese and non-obese patients |  | 12 hours | 
| Maximum concentration (Cmax) of acyclovir in obese and non-obese patients |  | 12 hours | 
| Time to maximum concentration (Tmax) of acyclovir in obese and non-obese patients |  | 12 hours | 
| Volume of distribution (Vd) of acyclovir in obese and non-obese patients |  | 12 hours | 
| Systemic Clearance of acyclovir in obese and non-obese patients |  | 12 hours | 
| Time that concentration is above IC50 for varicella and herpes viruses in obese and non-obese patients |  | 12 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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pharmacokinetics, acyclovir