gms | German Medical Science

Silexan¹ is a patented active substance containing an essential oil produced from Lavandula angustifolia flowers by steam distillation.

In Germany, the medicinal product Silexan has a marketing authorisation for the treatment of restlessness accompanying anxious moods. Silexan is being developed for the treatment of patients with syndromal and sub-threshold anxiety.

Silexan causes a nonselective reduction of the calcium influx through N-type, P/Q-type and T-type VOCCs.

Animal studies with Silexan show no evidence of a teratogenic effect or for an impairment of fertility or fetal development. In chronic toxicity studies the No Observed Effect Level (NOEL) is about 200-fold higher than the recommended dose in humans. Tests for genotoxic effects and mutagenicity were negative. No adverse effects on cardiovascular, central nervous or respiratory functions were observed.

Human pharmacokinetic studies performed with Silexan demonstrate a rapid absorption and plasma elimination of linalool with t_1/2 at about 4 hours after a single dose and about 9 hours after 14 days of once daily administration of 160 mg. Upon multiple dosing the steady state is reached after about 5 days.

While the recommended therapeutic dose of Silexan is 80 mg studies in healthy volunteers included single doses of up to 640 mg and multiple doses of up to 320 mg/day given for 14 days.

Silexan had no relevant effect on the in vivo activity of major cytochrome P450CYP enzymes and therefore respective metabolic drug-drug interactions are not to be expected. Accordingly, it showed no interaction potential on ethinyl estradiol and levonorgestrel pharmacokinetics and had no impact on the contraceptive efficacy of the tested oral contraceptive.

In patients treated with Silexan Hamilton Anxiety Scale total score reductions between baseline and end of treatment were significantly superior to placebo and comparable to lorazepam (in its starting dose) and paroxetine. Silexan had beneficial effects on typical co-morbidity symptoms of anxiety disorders, e. g. depressive mood, disturbed sleep, somatic complaints or decreased quality of life.

Except for gastrointestinal complaints (mainly eructation) and allergic skin reactions the drug is devoid of adverse effects. Silexan shows no sedative effects, has no potential for drug abuse and did not cause withdrawal symptoms at daily doses of 80 or 160 mg.

Note: ¹ Silexan^® is the active substance of LASEA^® (Dr. Willmar Schwabe GmbH & Co. KG, Karlsruhe, Germany).