Cannabis has long been known to help ease pain in multiple sclerosis sufferers, and after 11 years in development the first cannabis-containing prescription drug has been released to the UK market.

Sativex was developed by GW Pharmaceuticals – who have been growing cannabis at secret locations in England – and will be marketed by German company Bayer AG.

In June the UK Medicines and Healthcare product Regulatory Agency approved its use by as a treatment for spasticity – spasms, cramps and other similar symptoms – in multiple sclerosis patients who aren’t benefitting from other treatments. Its approval follows successful clinical trials and will cost the NHS around £11 per day for each patient.

Justin Gover, GW Pharmaceuticals’ managing director said: “Roughly one-third of multiple sclerosis patients are believed to have tried cannabis to get relief, with some surveys suggesting the proportion is as high as 43%.”

Bayer AG estimate that 100,000 people suffer from multiple sclerosis and that 11,500 people in the UK will be eligible for treatment with the drug, but only half will get a good response.

“The formal launch of Sativex represents a milestone in treating the disease,” said Pam Macfarlane, chief executive of the MS Trust, a charity which has campaigned for a licensed medicine derived from cannabis to be made available.