Effects of oral alcohol administration on heat pain threshold and ratings of supra-threshold stimuli

Abstract

Background and aimsEvidence for analgesic effects of oral alcohol consumption on heat pain has recently been documented in a placebo-controlled, randomized and double-blind design. We aimed at further investigating these effects and now set the focus on pain threshold and the ratings of supra-threshold pain to cover most of the pain range. Moreover, we now firstly evaluated sex differences in these effects.MethodsWe investigated 41 healthy participants (22 females) in a randomized, double-blind and placebo-controlled design and targeted two different moderate breath-alcohol levels of 0.06% and 0.08%. Before and after an alcoholic or placebo drink, contact heat was applied at the forearm. Subjects evaluated pain threshold (method of adjustment) and rated pain intensity and pain unpleasantness of supra-threshold stimuli (intensity: threshold +3 °C; duration: 5 s).ResultsAnalgesic effects taking the form of increased pain thresholds were found after both alcohol doses, surprisingly with more pronounced effects for the lower dose. While the high alcohol dose exerted small analgesic effects on pain intensity ratings (i.e. decrease), slightly increased ratings of pain intensity and pain unpleasantness after the low alcohol dose rather suggest pain enhancement. Alcohol did not affect intensity vs. unpleasantness ratings differentially. We found no evidence for sex differences in any of these effects.ConclusionsOverall, acute alcohol effects on pain were subtle. Our findings suggest that while low alcohol doses already exert analgesic effects on pain threshold, stronger doses are required for pain reduction on supra-threshold pain levels. Furthermore, sex differences could not be detected within our experimental paradigm but should be further explored in future research.ImplicationsAnalgesic effects of sub-toxic alcohol doses – as normally occurring during social drinking – might be weak; however, susceptibility to pain relieving effects of alcohol might be a risk factor for the use of alcohol as self-medication in acute pain states.

Analgesic effects of alcohol in adults with chronic jaw pain

“…Taken together, our findings are in line with recent literature supporting the analgesic properties of alcohol in producing clinically relevant reductions in ratings of pain intensity and increases in pain threshold (Capito et al, 2020; Thompson et al, 2017; Williams et al, 2021). Of note, there is limited prior research on the effects of acute alcohol intake on pain unpleasantness, with a single study demonstrating a statistically significant increase in pain unpleasantness under a lower alcohol dose (0.06%) and no significant changes under a moderate alcohol dose (0.08%) in response to heat pain stimuli (Capito et al, 2020). Given our use of pressure‐based pain stimuli in the present study, additional research is needed to determine whether mixed findings regarding pain unpleasantness depend on stimulus modality or other methodological differences (e.g., administration of both low and moderate alcohol doses).…”

Relationship between Alcohol Intake and Chronic Pain with Depressive Symptoms: A Cross-Sectional Analysis of the Shika Study

“…In contrast, a moderate alcohol intake has been reported to exert analgesic effects. A randomized, double-blind, and placebo-controlled intervention study on healthy adults by Capito et al [ 10 ] demonstrated that low doses of alcohol were particularly effective for analgesia. As an underlying mechanism for the analgesic effects of alcohol intake, Lovinger and Roberto [ 11 ] considered a decrease in excitatory neurotransmission due to the rapid inhibition of the ionotropic glutamate receptor activity of alcohol.…”

“…Regarding the relationship between alcohol intake and CP, previous studies have demonstrated that neuropathic pain due to an excessive alcohol intake [ 6 , 7 ], biogenic amines present in alcohol [ 8 ], or increased blood serotonin levels after drinking [ 9 ] may trigger headaches. However, moderate drinking has been shown to exert analgesic effects [ 10 , 11 , 12 ]. Therefore, the relationship between alcohol intake and CP has not yet been elucidated in detail.…”

Alcohol use and the pain system

“…Interestingly, reward loss also induces a reduced sensitivity to nociceptive-pain (hypoalgesia) which appears to reflect activation of a compensatory opioid and cannabinoid system to modulate physical and psychological pain as a component of homeostatic and allostatic modifications [ 74 ]. It is clear that low or moderate amounts of consumed alcohol also exerts clinically relevant hypoalgesic effects in controlled experimental studies with people and animals [ 50 , 55 , 56 , 139 ]. Similar effects of alcohol and endogenous opioids on nociceptive-pain suggest an intersection of neural circuits, more specifically the opioid-mediated regulation of GABA neurotransmission [ 109 , 140 ].…”