Due to the wide range of interpatient variability, the dosage must be individualized to each patient with the normal dose ranging from 0.5 mg/kg to 25.8 mg/kg. Various factors can affect the therapeutic dose range including age, body fat percentage, and the pathophysiology of the patient. As people age the excretory capacity of their kidneys decreases which can cause the body to take a longer time clearing the drug, therefore the dose should be decreased for elderly patients to reduce the risk of toxicity. In contrast to this, people who are obese have an increase in body weight which correlates to an increase in clearance which may require a higher dose. The main body process that affects dosage is kidney impairments; these patients must have a reduced dosage due to the fact that aminoglycosides are excreted mainly by the kidneys and an impairment could drastically increase the half-life, resulting in toxicity.