Altered gentamicin distribution in ascitic patients.

Gentamicin pharmacokinetics were studied in eight patients with ascites. Gentamicin serum levels were measured by radioimmunoassay immediately before, 15 minutes after, and at one and two estimated half-lives after intermittent i.v. infusions of gentamicin. Volumes of distributions (Vd) calculated for the eight patients were significantly larger than mean values reported for the drug in normal patients (p less than 0.025). Vd ranged from 20.2 to 53 liters and correlated poorly with lean and total body weights. In patients with ascites or abnormal extracellular fluid volumes, gentamicin dosage should be based on frequent measurements of serum gentamicin levels and on clinical response.