Celecoxib

Celecoxib, sold under the brand name Celebrex among others, is a COX-2 selective nonsteroidal anti-inflammatory drug (NSAID). It is used to treat the pain and inflammation of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, acute pain in adults, painful menstruation, and juvenile rheumatoid arthritis in people two years or older.

Side Effects
Using nonsteroidal anti-inflammatory precautions is recommended to avoid gastrointestinal side effects. Hepatic and renal dysfunction may occur, and peripheral edema. Central nervous system side effects include "dizziness, headaches, drowsiness and evidence of hypersensitives."

More commonly reported ones are:
 * Gastrointestinal side-effects including bleeding.

More commonly reported ones in children are:

Less commonly reported ones are:

Evidence
The Canadian Consensus Criteria suggests Celecoxib for pain in ME/CFS.

Dose
A dose of 100mg, as needed, up to twice a day, is suggested by the Canadian Consensus Criteria.