A Study to Compare Sublingual Cannabis Based Medicine Extracts With Placebo to Treat Brachial Plexus Injury Pain

Inclusion Criteria: * Aged 18 years or above. * Brachial plexus pain, at least 18 months after the initial injury. * Reported weekly brachial plexus pain at the required severity at Visits 1 and 2; a Box Scale-11 pain severity score of four boxes or above. * A pattern of pain that in the Investigator's opinion had been stable during the four weeks before study entry. * Stable regular medication during the four weeks before study entry. * A maximum tricyclic antidepressant dose of 75 mg per day, if applicable. * No cannabinoid use (cannabis, Marinol® or Nabilone) at least seven days before study entry or during the study. * If sexually active; was either using effective contraception during the study and for three months thereafter or had been surgically sterilised or, if female, was post-menopausal. All patients agreed to use a barrier method of contraception in addition to their usual form of oral or depot contraception. * Willing and able to undertake and comply with all study requirements. * Willing and able to consider and understand the patient information leaflet and consent form and to give informed consent. Those patients unable to read or to sign the document were managed as detailed in the Declaration of Helsinki. * Willing for his or her general practitioner, and consultant if appropriate, to be informed of study participation. * Willing for his or her name to be notified to Home Office for participation in the study. Exclusion Criteria: * Abuse or strong suspic…