Abstract
Noxious digital nerve stimulation leads to transient suppression of the electromyographic activity in isometrically contracted hand muscles, known as the "cutaneous silent period" (CSP). To date, neurotransmitters potentially involved in mediating this electromyographic (EMG) suppression remain unknown.
Anecdotal observation lead to the hypothesis that antihistaminic medication may counteract nociceptive EMG suppression, as CSPs in one male subject who was accustomed to CSP recordings were temporarily lost following ingestion of an antihistaminic drug for acute rhinitis. A second otherwise healthy male subject, who was on long-term cetirizine for allergic rhinitis, presented without clearly defined CSPs when volunteering for normal values.
Results: CSP onset latency, CSP end latency and CSP duration, as well as the index of suppression did not change significantly following ingestion of 10 mg cetirizine. Repeat study in the subject with no clearly defined CSPs on long-term treatment revealed persistently absent CSPs after a 5-week withdrawal from cetirizine.