Diclofenac potassium is a nonsteroidal anti-inflammatory drug (NSAID) used as an active pharmaceutical ingredient (API) for relieving pain and reducing inflammation. It is effective in treating conditions such as arthritis, muscle pain, and menstrual cramps. The potassium salt formulation allows for rapid absorption and onset of action. Common side effects may include gastrointestinal discomfort, headache, and dizziness, necessitating caution in prolonged use.