Overview
Hyoscine hydrobromide, also known as scopolamine, is an anticholinergic medication primarily used to prevent motion sickness and postoperative nausea and vomiting. It can also be used to reduce saliva production.

Mechanism of Action
It acts as a competitive antagonist at muscarinic acetylcholine receptors, particularly in the central nervous system. By blocking cholinergic transmission to the vomiting center, it effectively prevents motion sickness.

Dosage and Administration
For motion sickness, it is often administered as a transdermal patch applied behind the ear 4 to 6 hours before travel. Oral or injectable forms are also available for other indications.

Side Effects
Common side effects include dry mouth, drowsiness, blurred vision, dilated pupils, and urinary retention. In elderly patients, it can cause confusion or delirium.

Contraindications
Contraindicated in patients with narrow-angle glaucoma, myasthenia gravis, severe gastrointestinal obstruction, or urinary retention.

Pregnancy and Lactation
Use with caution during pregnancy; it crosses the placenta. It is excreted in breast milk, and caution is advised during breastfeeding.