Heavy users of a group of pain medicines prescribed to nearly 400,000 New Zealanders a year have been warned about its links to an increased risk of heart attacks and strokes.
Long-term use of diclofenac at high doses is associated with a "very small increased risk" of cardiovascular events, says the Government's medicines safety authority, Medsafe.
Diclofenac is the active ingredient in Voltaren, Diclax and several other medicines in the much larger class known as non-steroidal anti-inflammatory drugs or N-SAIDs. Small-dose, short-term courses of diclofenac can be bought from a pharmacist; larger doses to treat an ongoing disorder require a doctor's prescription.
People with arthritis tend to be big users of N-SAIDs drugs to control their pain.