Potential Psychotropic Activity of Phlebotropic Drugs: Weak Interactions with Brain Benzodiazepine Receptors

Abstract

Background:

Epidemiological and psychometric studies have provided evidence that some symptoms of venous disease might reflect a psychosomatic rather than organic disorder. Traditionally, plant extracts are prescribed to alleviate such symptoms. Since benzodiazepines (BZ) and BZ-like compounds are present in various plants, we studied potential interactions of ‘phlebotropic’ drugs with BZ receptors.

Methods:

Six drug preparations used in phlebology and extracts of hop and valerian were tested for neuronal and mitochondrial BZ receptor binding activity in vitro. In addition, plasma samples of volunteers who ingested phlebotropic drugs for 3 weeks were assayed for the presence of BZ-like activity.

Results:

All phlebotropic drug preparations interacted weakly with central and/or peripheral BZ receptors in vitro. Their diazepam-equivalent concentrations were, however, too low to be of pharmacological relevance. No binding activity was recovered in the blood of volunteers pretreated with phlebotropic drugs.

Conclusion:

The positive influence of so-called ‘phlebotropic’ drugs on the subjective symptoms of venous disease is not mediated through BZ receptors.