A simple cold pressure technique for the evaluation of analgesic drugs in healthy subjects

AIM: An experimental pain model which is sensitive and reproducible would be a useful pharmacological tool both for existing and new drugs. The aim of the present study was to establish a simple and reliable method of producing experimental pain which can be used for screening of analgesic agents. MATERIALS AND METHODS: The method was standardized by recording pain threshold and pain tolerance values in 24 healthy volunteers. Reproducibility of the test procedure was evaluated by recording the pain threshold and pain tolerance values by a single observer on two sessions (inter-day reproducibility), and second observer in one session (inter-observer reproducibility), separately. Validity of the model was further tested by evaluating the analgesic effect of tramadol in 12 healthy volunteers. RESULTS: Cold pain model was found to produce low variability with coefficient of variation less than 15%. Inter-observer and inter-day reproducibility was very good as shown by Bland – Altman plot with most of the values within ± 2SD. Analgesic activity by Tramadol was statistically different from placebo (P < 0.05). CONCLUSION: The newly developed pain model offers a stable and sensitive method for the early assessment of analgesic activity.