Prospective Evaluation of Adjusted Body Weight Dosing of Acyclovir in Obesity

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.