Fibromyalgia is a condition that causes widespread pain and tenderness in the body. This study will test a drug called AXS-14 to see if it helps people with fibromyalgia. The study is divided into two parts: a 12-week period where everyone gets AXS-14, and another 12-week period where some continue with AXS-14 and others switch to a placebo (a "sugar pill" with no medicine) without knowing which one they are taking. This is a double-blind study, meaning neither the participants nor the researchers know who is receiving the actual medicine during the second part.

• The study lasts for a total of 24 weeks.
• Participants must be at least 18 years old and have fibromyalgia.
• If participants have previously used similar drugs, they cannot join.

Participants are expected to follow study procedures and may exit the study if the treatment stops working. Joining this study requires informed consent, meaning participants agree to all study details before starting.