Comparison of Five Experimental Pain Tests to Measure Analgesic Effects of Alfentanil

Abstract

Electrical, pressure, and ice-water pain, but not ischemic and heat pain, provide significant concentration-response curves in the clinically relevant range of 200 ng/ml alfentanil or lower. The power to detect a clinically relevant shift of the curve is similar in the three tests. The appropriate test(s) for pharmacodynamic studies should be chosen according to the investigated drug(s) and the study design.

Assessing analgesic actions of opioids by experimental pain models in healthy volunteers – an updated review

“…However it has been shown that in experimental models with a high reproducibility sample sizes below 10 are powered to show the effect of analgesics [7]. Accordingly we found a well designed study with a sample size of seven, and this was the minimum sample size for the studies included in this review [8].…”

“…In the study by Black et al both pain intensity and the affective component 'bothersomeness' was scored and alfentanil reduced both parameters [8,52].…”

“…Short acting opioids with strong affinity for the m-opioid receptor Alfentanil (Table 2) Acute models Skin/teeth: Alfentanil has been tested in several acute models in the skin using heat, cold and electrical stimulation [8,[44][45][46][47][48][49]. The tested models were generally all sensitive to alfentanil.…”

“…Alfentanil showed analgesic effects in tests involving electrical stimulation (both repeated and single stimulation), pressure, cold pressor test and injection of hypertonic saline [8,44,45,48,53]. The tourniquet model (evoking muscle ischaemia mainly), with continuous pain assessment for 120 s and area under the visual analogue scale (VAS) curve used as a pain measure, was not sensitive to alfentanil [8].…”

“…The tourniquet model (evoking muscle ischaemia mainly), with continuous pain assessment for 120 s and area under the visual analogue scale (VAS) curve used as a pain measure, was not sensitive to alfentanil [8].…”