IT IS rumoured that Queen Victoria swore by it for soothing her period pains – now scientists in Westminster are using cannabis as the basis for a new painkiller. Researchers at Imperial College in Paddington have discovered receptors in the nervous syste

IT IS rumoured that Queen Victoria swore by it for soothing her period pains - now scientists in Westminster are using cannabis as the basis for a new painkiller.

Researchers at Imperial College in Paddington have discovered receptors in the nervous system called CB2 that can be activated by cannabis, and developed painkillers that replicate this effect without harming the brain.

Drugs that activate CB2 receptors block pain by stopping signals being transmitted in human sensory nerves.

Previously, CB1 receptors were thought to be the primary cell structures involved in pain relief, but drugs that activate these can cause drowsiness, psychosis and addiction.

"Although cannabis is probably best known as an illegal recreational drug, people have used it for medicinal purposes for centuries," said Praveen Anand, professor of clinical neurology at Imperial.

"Queen Victoria used it in tea to help with her period pains, and people with a variety of conditions say that it helps alleviate their symptoms.

"Our new study is very promising because it suggests that we could alleviate pain by targeting the cannabinoid receptor CB2 without causing the kinds of side effects we associate with people using cannabis itself."

It is believed the new drugs will be able to treat conditions such as osteoarthritis and nerve damage that have few effective and safe therapies. They could also provide an alternative to powerful opiates such as morphine that can cause dependency, nausea and vomiting.

Researchers will conduct clinical trials on patients with chronic pain at the Imperial NHS Trust, which runs St Mary's Hospital.

Jane Tadman, from the Arthritis Research Campaign (ARC), agrees that cannabis has important pain-relieving properties.

She said: "Due to side effects of current painkillers for osteoarthritis, such as increased risk of heart attack and stroke, millions are in desperate need of alternatives.