Comparative pharmacokinetic study of conventional and sustained-release viloxazine in normal volunteers.

Animal and human studies have indicated that viloxazine hydrochloride, an antidepressant drug with a half-life of 3-4 h in most subjects at low dosage, is rapidly and almost completely absorbed after oral administration. A sustained-release form might be useful to decrease the frequency of administration. In our study, the pharmacokinetics of sustained-release form containing 300 mg viloxazine were compared with 300 mg conventional viloxazine in 11 normal volunteers (6 women, 5 men). Wide interindividual variations were observed with respect to plasma levels, but there was no significant statistical correlation between weight and blood concentration (conventional form: Cmax = 3,599 +/- 579 ng/ml, tmax = 86 +/- 26 min; sustained-release form: Cmax = 1,917 +/- 922 ng/ml, tmax = 215 +/- 77 min). Twelve hours after administration, plasma levels ranged between 540 and 1,600 ng/ml for the conventional form and between 660 and 2,120 ng/ml for the sustained-release form. Despite the great interindividual variation this new viloxazine form appears to be of interest for one daily administration.

Pharmacokinetics and haemodynamic effects of prolonged methohexitone infusion.

1. The use of continuous infusion anaesthesia has only been of interest since the development of short-acting, less cumulative and less toxic drugs. 2. This study aimed to compare pharmacokinetics and haemodynamic effects during and after long time methohexitone constant rate infusion. Sixteen patients were given either 60 or 90 micrograms kg-1 min-1 methohexitone during 14 h. Blood samples were taken hourly during this time and 12 h following the end of infusion. 3. Infusion period was analysed by a single exponential model; post-infusion time showed a three compartment model, the intermediate phase parameters corresponding to those of the infusion period. 4. Methohexitone was haemodynamically well tolerated; prolonged infusion decreases oxygen consumption, mainly by a decrease in oxygen demand. 5. Many patients remained unconscious for unacceptably long periods of time after post-operative sedation by methohexitone.