Influence of age on the pharmacokinetics of ceftazidime in acutely ill, adult patients.

The single and multiple i.v. dose pharmacokinetics of ceftazidime were investigated in 37 acutely ill patients with normal age-related glomerular function. Distribution was rapid with similar t1/2 alpha at all ages. Compared to the younger patients, elderly subjects had lower total and renal clearances and reduced urinary recovery. Ceftazidime clearance was closely correlated with glomerular function. The t1/2 beta was approximately 2 h in young and middle-aged patients, 2.73 h in patients aged 60-79 years, and 3.54 h in those above 80 years. The AUC was more than doubled in the oldest patients compared to individuals younger than 40 years. Vss did not change with advancing age, but was larger than previously reported in healthy volunteers. Elimination variables were not altered during multiple dosing, but a small but significant increase in AUC was detected in the elderly. Dose reduction by 50% in patients more than 70 years old is suggested.