A randomised double-blind crossover trial of the potential analgesic effect of a transdermal nicotine patch in non-smokers based on objective and subjective assessment

OBJECTIVEThe results of studies of the analgesic effect of nicotine in humans are complex because these studies have included smokers with variable smoking histories. We investigated whether the use of a 17.5 mg transdermal nicotine (TDN) patch decreased the magnitude of pressure pain on the hands of healthy non-smoking volunteers. DESIGNThis was a randomised double-blind crossover trial. A TDN patch or placebo (drug-free bandage) was applied randomly on the anterior chest of non-smoking volunteers 12 h before the experiments. We measured minimum perceived current and pain threshold on the right hand and then evaluated the magnitude of pressure pain by using the Pain Vision PS-2100 (Nipro Co., Osaka, Japan) which helps in objective quantitative assessment of pain magnitude. After estimating minimum perceived current, pressure pain was produced using a combination of 100-g discs and a rod. The rod and the discs weighing 0 (no disc), 200 (two discs), 400 (four discs), 200 (two discs) and 0 g (no disc) were placed consecutively in this order on the right hand and pain threshold was measured. At the same time, volunteers were asked to rate pain on a numerical rating scale (NRS). Minimum perceived current is the current at which the volunteer perceives the first sensation on applying gradually increasing pulsed current. Pain threshold is the compatible electrode current at which the volunteer feels the intensity of pressure pain. Pain degree is calculated as (pain threshold − minimum perceived current)/minimum perceived current × 100. PARTICIPANTSForty non-smoking volunteers were enrolled in this study. RESULTSNo significant differences between groups were observed in minimum perceived current, pain threshold, pain degree or NRS. Of the volunteers who received the nicotine patch, four became anorexic and nauseated and two required anti-emetics. CONCLUSIONThe nicotine patch had no analgesic effect in non-smoking volunteers.