Synarel (generic: nafarelin) is a prescription medication used to treat women with symptoms of endometriosis including severe menstrual cramps, pain during sexual intercourse, low back pain, and painful bowel movements. It is also used to treat abnormally early sexual development in children, known medically as central precocious puberty (CPP). 

Synarel belongs to a group of drugs called synthetic hormones, which help control hormone levels in the body.

This medication comes in the form of a nasal spray. In treating endometriosis, one spray is inhaled in one nostril in the morning, and one spray is inhaled in the other nostril in the evening. In treating CPP, two sprays are inhaled in each nostril every morning.

Common side effects of Synarel include acne, breast enlargement, and vaginal bleeding.