icatibant and Pain--Postoperative

Icatibant is a selective antagonist of the bradykinin type 2 receptor. In the randomized, double-blind, multicentre, FAST-1 trial, the difference in the median time to the onset of symptom relief (primary endpoint) did not reach statistical significance between a single dose of subcutaneous icatibant 30 mg and placebo in adults with moderate to very severe acute abdominal or cutaneous episodes of hereditary angioedema. However, icatibant was effective with regard to several other endpoints, providing significantly greater reductions from baseline in symptom severity scores 4 and 12 hours after administration, and eliciting significantly shorter times to both first symptom improvement and overall patient improvement than placebo. In the similarly designed, active comparator-controlled, FAST-2 trial, a single dose of subcutaneous icatibant 30 mg was associated with a significantly shorter median time to onset of symptom relief (primary endpoint) than oral tranexamic acid in adults with acute abdominal or cutaneous episodes of hereditary angioedema, and was also more effective than tranexamic acid in terms of most other endpoints. Across both FAST-1 and -2, the efficacy of subcutaneous icatibant 30 mg in the treatment of laryngeal episodes of hereditary angioedema was generally consistent with that seen for abdominal and cutaneous episodes, with a median time to first symptom improvement of 0.6-1.0 hours. Subcutaneous icatibant was generally well tolerated in adult patients with hereditary angioedema in the FAST trials, with the most common adverse events being injection-site reactions that were generally of mild severity, transient in nature and resolved spontaneously without treatment.

Topics: Adult; Angioedemas, Hereditary; Bradykinin; Bradykinin B2 Receptor Antagonists; Bronchodilator Agents; Calcium Channel Blockers; Chemistry, Pharmaceutical; Clinical Trials as Topic; Dose-Response Relationship, Drug; Double-Blind Method; Drug Administration Schedule; Drug Therapy, Combination; Humans; Infusions, Intravenous; Injections, Intravenous; Meta-Analysis as Topic; Pain Measurement; Pain, Postoperative; Serotonin Receptor Agonists; Tooth Extraction; Treatment Outcome

Bradykinin, an endogenous nonapeptide and an important mediator of inflammation, is also implicated in the initiation and maintenance of pain. Both des-Arg(8), Leu(8)-bradykinin (dALBK) and HOE-140, the prototypic bradykinin B1 and B2 receptor antagonists, respectively, have been shown to reduce pain behaviors and inflammation in animal models of persistent nociception. We studied them for activity against incision-induced pain behaviors in a rat model for postoperative pain. A 1-cm plantar incision was made in the hind paw of halothane-anesthetized rats and closed with 5-0 nylon. Withdrawal responses to punctate and nonpunctate mechanical stimuli were tested with von Frey filaments and a plastic disk attached to a von Frey filament, respectively. Withdrawal latency to radiant heat was also tested. Rats were tested 1 day before the incision, 1 h after the incision, and 0.5, 1, 1.5, and 2.5 h after the injection of the drug. They were then retested at the same times before and after the injection of the drug on each of the first 2 postoperative days. The rats received the saline vehicle dALBK (0.1, 0.3, 1.0, or 3.0 mg/kg) or HOE-140 (0.1, 0.3, 1.0, or 3.0 mg/kg) IV. Another group of rats had the drug injected 1 h before incision and tested as above. Statistical significance (P < 0.05) was determined with Kruskal-Wallis test and a two-way analysis of variance. None of the doses of either dALBK or HOE-140 affected the responses to punctate or blunt mechanical stimulation or heat, either as a pretreatment or as a posttreatment. These data support the unique mechanisms for incision-induced pain relative to inflammation-related pain. Although inflammation may represent a component of incisional pain, the etiology of inflammation and its role seem different than in other models.

Topics: Analgesics; Animals; Behavior, Animal; Bradykinin; Dose-Response Relationship, Drug; Foot; Hot Temperature; Male; Pain Measurement; Pain, Postoperative; Physical Stimulation; Rats; Rats, Sprague-Dawley