Study To Assess The Effect Of Gabapentin, Diphenhydramine And Morphine On Cold Pain In Healthy Male Volunteers

A Randomised, Double-Blind, Double-Dummy, Placebo And Active Controlled, 4-Way Crossover Methodology Study To Assess The Effect Of Gabapentin, Diphenhydramine And Morphine On Cold Pain In Healthy Male Volunteers

Human experimental pain models are useful in understanding the mechanisms underlying clinical pain conditions and can be used to test the analgesic efficacy of drugs used in the management of pain. Once established these models can be used as mechanism biomarkers in early development clinical studies to establish proof of mechanism for novel compounds. The cold pain model is a mechanistic pain biomarker with potential application in proof of mechanism studies. In this study we aim to set up this cold pain model at a Clinical Research Unit and demonstrate we can effectively screen subjects for this model and examine the effect of morphine, diphenhydramine, and gabapentin in the cold pain model.

Cold pain methodology development

Inclusion Criteria:

• Healthy male volunteers having given consent to participate in the study who have no clinically significant anomalies and whose vital signs are within normal range.
• Subject having performed the cold pain test reproducibly ie, if the area under the pain-time curve (AUC) must be within 20% during successive tests within one cold pain test screening visit and within 30% between the two cold pain test screening visits.

Exclusion Criteria:

• Subject who have had a serious adverse reaction or significant hypersensitivity to any of the study drugs.
• Subjects with a history of or evidence of any neurological condition which could affect pain sensation.
• Subjects with an AUCcpt 0-120 sec in the cold pain test of <1000 in any of the screening tests (excluding familiarization).