Aztreonam in the treatment of serious gram-negative infections in the elderly.

The efficacy and safety of aztreonam in the treatment of serious gam-negative infections were investigated in 20 patients, 19 of whom were more than 60 years old. There were 13 cases of upper urinary tract infection, 6 of septicemia and one of peritonitis. Half the patients were in a critical clinical condition with significant severe underlying disease. Aztreonam was given i.v. or i.m. in doses ranging from 1.5 to 4 g/day according to the severity of the infection. The duration of treatment ranged from 7 to 20 days. In 5 patients with mixed infections due to gram-positive and anaerobic organisms in addition to gram-negative pathogens, aztreonam was given in combination with clindamycin and metronidazole as appropriate. Clinical and bacteriological cures were observed in all 20 patients. There were two cases of reinfection and 3 of superinfection--all occurred in patients with severe underlying disease. Untoward effects were few and of minor severity. Creatinine clearance remained stable or improved during aztreonam treatment, even in patients with significant renal impairment. In conclusion, aztreonam was shown to be both effective and safe in the treatment of serious gram-negative infections in elderly patients--even those with impaired renal function. In such indications aztreonam appears to be a good alternative to potentially toxic drugs such as the aminoglycosides.

Pharmacokinetic study of cefuroxime in the elderly.

1 The pharmacokinetics of cefuroxime have been investigated in 18 patients at least 70 years old. The drug was given either by continuous infusion (7 cases) or by multiple injections (11 cases) for 3 to 11 days (mean duration: 7 days). 2 The unchanged drug was assayed in blood plasma and in the urine by high performance liquid chromatography (h.p.l.c). 3 Cefuroxime was cleared, unchanged, almost exclusively by the kidneys, even when kidney function was impaired. Creatinine clearance ranged from 1.02 to 4.08 1/h (17 to 68 ml/min) in this group of patients and plasma clearance of cefuroxime varied from 1.02 to 8.16 1/h (17 to 136 ml/min) (r = 0.7 P less than 0.001 for linear correlation), but the apparent rate constant for nonrenal elimination remained quite small (average: 0.04 h-1) and independent of creatinine clearance (r = 0.06, n = 17). 4 Since creatinine clearance decreases sharply with age, it might be suggested that cefuroxime dosage be related to creatinine clearance in the elderly, even when no renal impairment is suspected.