Which medication is commonly used to treat constipation?

Dulcolax, also known as bisacodyl, is an over-the-counter laxative commonly used to treat constipation. It works by stimulating bowel movements and is effective in relieving occasional constipation. Dulcolax is typically taken orally or can be administered rectally in the form of suppositories, providing flexibility for patients based on their preferences or needs.

The other medications mentioned serve different purposes; Allegra is an antihistamine used to relieve allergy symptoms, Benadryl is also an antihistamine commonly used for allergies and as a sleep aid, and Flonase is a nasal spray utilized for treating nasal symptoms associated with allergies. None of these options addresses the treatment of constipation, highlighting why Dulcolax is the most appropriate choice for this condition.