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The effects upon vigilance and reaction speed of the addition of ephedrine hydrochloride to chlorpheniramine maleate


The addition of the stimulant, ephedrine hydrochloride (15 mg), to the antihistamine, chlorpheniramine maleate (10 mg) is shown significantly to reduce the adverse drowsy effects of the latter upon various components of human performance. Auditory vigilance — a test of long-term attentiveness — is shown particularly to benefit from the addition of ephedrine. Whilst ephedrine does not aid simple reaction speed, it does reduce the pausing in serialchoice performance, indicative of a drowsy state, which otherwise occurs under chlorpheniramine alone.

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Millar, K., Wilkinson, R.T. The effects upon vigilance and reaction speed of the addition of ephedrine hydrochloride to chlorpheniramine maleate. Eur J Clin Pharmacol 20, 351–357 (1981).

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Key words

  • chlorpheniramine
  • ephedrine
  • vigilance
  • reaction speed
  • antihistamine
  • stimulant