Pagoclone

Pagoclone is an anxiolytic drug from the cyclopyrrolone family, which is related to other more well known drugs such as the sleeping medication zopiclone. It is one of a relatively recently developed class of medicines known as the nonbenzodiazepines, which have similar effects to the older benzodiazepine group, but with quite different chemical structures.

Pagoclone was originally developed as an anti-anxiety drug, but never commercialised. It is a partial agonist acting at GABAA receptors in the brain. In contrast to zopiclone, pagoclone produces anxiolytic effects with little or no sedative or amnestic actions at low doses. This is because pagoclone is a subtype-selective drug which binds primarily to the α2/α3 subtypes of the GABAA receptor which are responsible for the anti-anxiety effects of these kind of drugs, but has relatively little efficacy at the α1 subtype which produces the sedative and memory loss effects.

David Nutt from the University of Bristol has suggested pagoclone as a possible base from which to make a better social drug, as it produces the positive effects of alcohol, such as relaxation and sociability, but without also causing the negative effects like aggression, amnesia, nausea, loss of coordination and liver damage. Its effect can be quickly reversed by the action of flumazenil, which is already used as an antidote to benzodiazepine overdose.

Dr. Nutt has published studies praising the potential of pagoclone which were financed by Indeveus which holds the patents to the pharmaceutical and is, as of Spring 2006, seeking funding for a possible production of the compound. The significance of this is undetermined, but it should be noted that the long-term safety of pagoclone has not been assessed. The abuse potential of pagoclone has been assessed as being similar to, or slightly less than that of diazepam and it would also be expected to be somewhat safer due to its relatively weaker sedative effects, but development of pagoclone as a recreational drug would still be unlikely due to concerns about abuse. Pagoclone is also being trialed as a drug to improve a stammerer's speech fluency.