Open-Label, Single-Dose Pharmacokinetic Study of Modafinil Tablets: Influence of Age and Gender in Normal Subjects



An open-label, single-center, single-dose, parallel-group study was performed in healthy young males and females as well as healthy elderly males to examine the influence of age and gender on the pharmacokinetics of modafinil following administration of a single 200 mg oral dose. Twelve subjects were enrolled in each of the following three groups: young males, young females, and elderly males. Each fasted (overnight) subject received 2 x 100 mg modafinil tablets.

Blood and urine samples were collected at various times up to 72 hours postdose for the determination of plasma and urine levels of modafinil as well as the acid and sulfone metabolites. The plasma concentrations of the individual isomers, d- and l-modafinil, were also determined. Pharmacokinetic parameters were determined by noncompartmental methods. Modafinil was well tolerated at a single oral dose of 200 mg. 

The most commonly reported adverse events were headache, fever, pharyngitis, and asthenia. There were no clinically meaningful differences with respect to the incidence rate of treatment-emergent adverse events among the young female, young male, and old male groups. Modafinil was rapidly absorbed after oral dosing and slowly cleared (t1/2 approximately 11-14 hr) from the body. Modafinil acid was the major urinary metabolite, which accounted for 35% to 60% of the dose. Results from this study indicated that there were age and gender effects on modafinil clearance processes. 

In this regard, the clearance rate of modafinil in males decreased with age while young females cleared modafinil at a faster rate than young males. Stereospecific pharmacokinetics of modafinil were also demonstrated. The d-modafinil was eliminated three times faster than the l-modafinil.

This post is a Research-Based topic follows the strictest sourcing guidelines in the health and nootropics industry. Our focus is to exclusively link to peer-reviewed studies found on respected websites, like PubMed. We focus on finding the most accurate information from the scientific source.

Our goal is to provide you with the most scientifically accurate, unbiased, and comprehensive information regarding Modafinil and Armodafinil.

All of our content is written by people with a strong science background, including medical researchers.

Our content is continually monitored by an internal peer-review process to ensure accuracy. We strive to never have a piece of inaccurate information on this website.

If you feel that any of our content is inaccurate or out-of-date, please contact us at: [email protected]