Pharmacokinetics and drug metabolism of antibiotics in the elderly

Introduction: The number of elderly people is increasing worldwide. The elderly may be at increased risk of bacterial infections compared with younger adults. Dosing adaptation of antibiotics in this population may be difficult due to changes in body composition, decline of renal function and/or drug–drug interactions. Lack of dose adaptation may cause unintentional overdosing with the risk of severe adverse effects. Areas covered: This review is based on a PubMed search of the literature published in English language and concerns pharmacokinetic (PK) studies of antibiotics in the elderly performed between 1971 and 2017. Expert opinion: Appropriateness of drug prescription in the elderly is a major commitment of the health care systems worldwide. This should push more and more clinicians to adjust the dosage of renally cleared antibiotics in relation to renal function estimates. The situation may become even more complex in frail elderly patients who are receiving polypharmacy due to drug–drug interactions. Development of new antibiotics should include within clinical trials adequate representation of patients aged ≥75 years to determine age-based dosing. Population PK could be helpful in increasing the knowledge of clinical factors influencing the need for dosing adaptation of the currently available antibiotics in the elderly.