Performance Studies with the H1-histamine Receptor Antagonists, Astemizole and Terfenadine

1 Effects of the antihistamines, terfenadine (60 mg) and astemizole (10 and 20 mg), on performance (visuo-motor coordination, arithmetical ability and digit symbol substitution) and on mood were studied in six healthy adult females. The study was double-blind, placebo controlled and included an antihistamine with known central effects (triprolidine 10 mg in sustained release form). 2 There were no changes in performance after terfenadine (60 mg) and astemizole (10 and 20 mg). Triprolidine (10 mg) caused a decrement in visuo-motor coordination (P less than 0.01) 0.5 h after ingestion which lasted until 3.5 h (P less than 0.001). The subject assessed their performance as impaired from 1.5-3.5 h (P less than 0.05) with triprolidine (10 mg), and their mood assessments were also altered. 3 Terfenadine (60 mg) and astemizole (10 and 20 mg) are likely to prove useful antihistamines for those involved in skilled activity.