Comparative study of the effects of oral and i.m. atropine and hyoscine in volunteers.

The effects of equivalent doses of atropine and hyoscine following oral and i.m. administration were assessed on salivary secretion, heart rate, arterial pressure, body temperature, pupillary size, near-point of vision and sweat-gland activity. The ratio of oral to i.m. doses of atropine on heart rate and salivary secretion appears to be 2:1 and that of hyoscine on salivary secretion about 5-6:1. Following oral administration the effects on the eye are minimal even after the highest doses of the two drugs, while the decrease in salivation is adequate.