Analgesic Effect of Acetylsalicylic Acid (ASA) Versus a Lithium-ASA combination: An Evoked Potential Study Employing Radiant Heat Stimulation with a CO₂Laser

Abstract

Objective experimental algesimetry was used to assess quantitative differences in analgesic properties between acetylsalicylic acid (ASA, 750 mg) and a special combination of ASA, trilithium citrate and quinine-2 HCl (750 mg, 126 mg, 4.5 mg) in a placebo-controlled double-blind crossover study on nine healthy subjects. Radiant heat stimulation was applied with a CO2 laser and somatosensory evoked vertex potentials (LSEP) were recorded while the subjects were simultaneously engaged in an adaptive pursuit tracking task in order to stabilize their vigilance. The N1 amplitude of the LSEP decreased under both verum medications; however, the drug combination was significantly more effective. The time course of this effect was attended by a marked intradiurnal variation of the LSEP amplitudes. The role of lithium in the combination with ASA and quinine-2 HCl (Togal) and an amplification of the analgesic potency of ASA are discussed.

Human Experimental Pain Models for Assessing the Therapeutic Efficacy of Analgesic Drugs

“…Kobal et al (1990) found only significant modulation of the evoked potentials and not subjective pain ratings after nasal gaseous CO 2 stimulation. Supporting this Schaffler et al (1987) found good effect of acetylsalicylic acid on the evoked vertex potential from radiant heat stimulation.…”

“…Skin, nasal, and dental mucosa. Acetylsalicylic acid has been tested against pain from radiant heat, electrical stimulation, nasal gaseous CO 2 stimulation, and infusion of low pH solutions (Cruccu et al, 1982;Schaffler et al, 1987;Steen et al, 1996). Kobal et al (1990) found only significant modulation of the evoked potentials and not subjective pain ratings after nasal gaseous CO 2 stimulation.…”

Assessing efficacy of non‐opioid analgesics in experimental pain models in healthy volunteers: an updated review

“…Acute models Skin/nasal and dental mucosa: Acetylsalicylic acid has been tested against pain from radiant heat, electrical stimulation, nasal gaseous CO2 stimulation and infusion of low-pH solutions [8][9][10]. Pain from repeated mechanical impact of the interdigital web is a classical model for detecting analgesia from nonsteroidal antiinflammatory drugs (NSAIDs), and this model is also sensitive to analgesia from acetylsalicylic acid [11].…”

“…Topical ibuprofen seemed to have some advantages over systemic ibuprofen for attenuation of exercise-induced jaw-muscle pain, indicating that a peripheral pain mechanism is important in this model [31]. Experimental models involving NSAIDs shows how a peripheral mediated analgesia can be detected by central measures, because the sum of incoming nociceptive activity to the central nervous system (CNS) is reduced [9]. Generally, it could be seen that evoked brain potentials from electrical skin stimulation were more sensitive than the subjective pain rating [13,20,38].…”

Effects of pentazocine and acetylsalicylic acid on pain-rating, pain-related evoked potentials and vigilance in relationship to pharmakokinetic parameters

“…It appears that the wide gap between preliminary experimental data obtained in animals and human pain should be bridged by quantitative measurement of drug effects in human volunteers in order to predict the possible clinical suitability of any compounds. Many attempts for measuring pain and analgesic effects in volunteers using event-related potentials [3] have been reported (reviewed by Chudler and Dong [4] and Stowell [5]; [6][7][8][9][10][11][12]). Many of these studies suffer either from limited reproducibility due to changes in the tissue irritated by the noxious stimulus, or from the lack of adequate control measurements which take into account vigilance, adaptation, and learning effects.…”