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Effects of intravenous propranolol on heat pain sensitivity in healthy men
Author(s) -
Schweinhardt P.,
Abulhasan Y.B.,
Koeva V.,
Balderi T.,
Kim D.J.,
Alhujairi M.,
Carli F.
Publication year - 2013
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1002/j.1532-2149.2012.00231.x
Subject(s) - anesthesia , propranolol , analgesic , medicine , sedation , blood pressure , placebo , crossover study , anxiety , threshold of pain , alternative medicine , pathology , psychiatry
Background Clinical studies have shown opioid‐sparing effects of β‐adrenergic antagonists perioperatively and β‐blockers are being investigated for chronic musculoskeletal pain. However, the direct analgesic effects of β‐blockers have rarely been examined in healthy humans. Methods In a randomized, counter‐balanced, double‐blind, within‐subject crossover design, we tested the effect of the lipophilic β‐blocker propranolol (0.035 mg/kg body weight i.v.) on heat pain sensitivity in 39 healthy males, compared with placebo. To test for peripheral versus central effects, the peripherally acting β‐blocker sotalol was also examined. Experimental stimuli were brief superficial noxious heat stimuli applied to the volar forearm. Non‐painful cold stimuli were included to test for specificity. Sedation, mood and anxiety were assessed to investigate potential mechanisms underlying any analgesic effect. β‐blocker effects on blood pressure were incorporated into the analysis because of a known inverse relationship between pain sensitivity and systolic blood pressure. Results Propranolol significantly decreased perceived intensity of heat pain stimuli but only in participants with small propranolol‐induced blood pressure decreases. Even in this group, the effect was small (4%). Propranolol did not influence perceived intensity of non‐noxious stimuli and had no effect on sedation, anxiety or mood. Sotalol did not influence heat pain sensitivity. Conclusions Propranolol decreased pain sensitivity but its analgesic effects were small and counteracted by blood pressure decreases. The analgesic effects were not mediated by peripheral β‐receptor blockade, sedation, mood or anxiety. The small effect indicates that the utility of β‐blockers for clinical pain must be related to factors that do not play a significant role for experimental pain.