IISNeP

Chronic pain can arise from direct damage to the nervous system, which is known as nerve or neuropathic pain. Examples include sciatica and the pains caused by shingles or diabetes. Neuropathic pain is pernicious and treatments are often ineffective or limited by side effects. Laboratory-based investigations suggest that mice have been bred so that their pain transmitting nerves lack a certain gene that encodes a protein called HCN2 and do not develop neuropathic pain at all. The HCN channel controls the initiation of electrical impulses within cells and is best known for its role in controlling the heartbeat. The HCN2 channel can be blocked by a drug called ivabradine.

Large studies have shown that ivabradine is a useful treatment for angina and prevents heart attacks. It is licenced for this use in the UK. It is known to be safe and effective but nobody has ever examined whether it might also reduce neuropathic pain. We wish to study whether ivabradine might influence the transmission and thus symptoms of neuropathic pain. We will recruit willing healthy volunteers to take part in this randomised, blind, placebo-controlled, cross-over study. We will temporarily induce neuropathic pain in an area of the forearm using capsaicin (the chemical that makes chilli peppers hot), and measure whether the symptoms are reduced if ivabradine has been taken beforehand. The symptoms can be measured with specialist nerve conduction tests. To avoid bias the volunteers will be blindfolded when they take the tablets with water, thereby making them unidentifiable. During the study, the volunteers will only need to take one tablet on each of their visits and all measurements will be completed within 3 days.

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