The cannabis is given using tamper-proof capsules in vaping devices and costs £299 per month per patient.
In 2018, medicinal cannabis was legalised in the United Kingdom, and three medications containing cannabis extracts were licenced for use on the NHS.
A spokesperson for the HRA told CannabisHealth magazine: “The Health Research Authority has reviewed and approved the CANPAIN feasibility study.
Tony Samios, from the private firm LVL Health, which is running the trial, said: “Doctors are very limited in what they can prescribe .