On Penicillin Levels in Young and Geriatric Subjects

Antimicrobial Therapy for the Elderly Patient

“…Recent pharmacokinetic data on penicillin in geriatric subjects or patients are limited, with most studies being done between 1950 and 1980. Using oral as well as intramuscular penicillin G, Leikola et al showed higher serum concentrations of penicillin at 30 minutes, 90 minutes, 3 hours, and 6 hours in 37 hospitalized geriatric patients (age range, 71–86 years) in comparison to 42 younger patients (age range, 15–33 years) 47 . Although creatinine clearances were not measured, the authors postulated that the higher serum levels in older patients were secondary to reduced renal clearance.…”

Pharmacodynamic Principles of Drug Therapy in the Aged*

“…Reduced tubular secretory capacity in the elderly is suggested by the observation that following intramuscular injections of antibiotics, including penicillin, dihydrostreptomycin and tetracycline, higher blood levels and longer plasma half‐lives are observed (24, 25, 51). Leikola and Vartia (24) found that the serum level of G‐penicillin, three hours after intramuscular injection, was 0.91 mcg/ml as opposed to 0.07 mcg/ml in younger patients. With dihydrostreptomycin and tetracycline, these authors found in a subsequent study (25), much higher blood levels of these two antibiotics in old patients compared to young patients.…”

“…For example, morphine is most toxic in young and old rats; the maximum degree of tolerance to its lethal effects is seen in the middle‐aged animal (23). Further, serum levels of antibiotics after intramuscular administration tend to be high in both very young and very old human subjects (24, 25). This has been explained on the basis of undeveloped renal function in the young and declining renal capacity in the aged.…”

Pharmacologic Aspects of Aging: A Survey of the Effect of Increasing Age on Drug Activity in Adults

“…Indeed the use of some antibiotics is contraindicated in the aged for this reason (131). Vartia and Leikola (135, 136) found serum levels of penicillin, dihydrostreptomycin and tetracycline to be higher in elderly subjects following intramuscular injection. The higher levels were attributed to decreased tubular excretion.…”