Diclofenac injection is a nonsteroidal anti-inflammatory drug (NSAID) used to treat adults with mild to moderate pain. It is used alone or given with other opioid (narcotic) pain medicines to treat adults with moderate to severe pain. 

Side Effects:
Upset stomach, nausea, heartburn, diarrhea, constipation, gas, headache, drowsiness, and dizziness may occur. 

Precautions:
This medicine may raise the risk of heart and blood vessel problems like heart attack and stroke.