This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
This represents approximately 30 per cent, of extract of belladonna. The commercial and widely used plasters are not identical with that described in the pharmacopeia in other than alkaloidal content.
Action and Uses: The application of extract of bella-donna to the skin secures a local anodyne effect which is employed for the relief of rheumatic and neuralgic pains and soreness. It is a serviceable application in acute inflammatory conditions. Belladonna plaster is often used to relieve palpitation of the heart.
Dosage: Plasters are not commonly made by pharmacists, but are supplied already spread by the manufacturers. They are usually prescribed by the size according to the area of skin to be covered.