The time course of action of (—)‐hyoscine after intramuscular injection

Abstract

1. Although (-)-hyoscine has been in clinical use for many years, there is little detailed information concerning the speed of absorption or duration of action of the drug after single intramuscular doses.2. The time course of action of the drug was therefore examined using biological methods, and measurements were made of saliva flow, pulse rate, pupil diameter and mental alertness for up to 8 hr after doses of 0.4, 0.2, 0.1 and 0.05 mg of the hydrobromide.3. These techniques gave comparable results and peak activity was achieved at 1-2 hr after dose and followed by a gradual decline over the 8 hr period.4. The results are compared with those of earlier experiments of a similar kind, and discussed in relation to their bearing on both therapeutics and experimental design.