Definition: Banisterine is a type of medication used to treat high blood pressure. It works by relaxing the muscles in the arteries, which helps lower blood pressure. Banisterine can be taken as an oral tablet or as a nasal spray. It's usually prescribed for people with hypertension who are taking other medicines, such as diuretics and beta-blockers. If you're unsure about taking banisterine, it's best to consult with your doctor.