Age-related differences in kinetics and side-effects of viloxazine in man and their clinical implications

Dose kinetics and side effects of viloxazine (VLX) in 16 healthy volunteers (range age 25-90 years) were studied after single oral administration of 200 mg of VLX. Significant differences in peak plasma values (P less than 0.01), t1/2 (P less than 0.01) and Cl/F (P less than 0.05) were found between subjects under 50 and over 60 years. Positive correlations were found between age and peak plasma values (P less than 0.05), age and AUC (P less than 0.01). No correlations were found between age, t1/2 and Cl/F, due to the high interindividual variability in pharmacokinetic profiles. Total reported and observed side effects scores were higher overall in subjects under 50 years than over 60 years and were inversely correlated to AUC (P less than 0.05). Drowsiness was inversely related to the age of subjects (P less than 0.05). Our data support the importance of single dose kinetic studies, particularly for new antidepressants, in relation to age, both to emphasize differences in pharmacokinetic profiles and to predict side effects during chronic treatment.