Naproxen

What it is

Naproxen is a non-steroidal anti-inflammatory drug sold without a prescription. It blocks the cyclo-oxygenase enzymes, so the body makes fewer prostaglandins, the signalling molecules behind pain, swelling and fever. It is used for pain and for inflammatory conditions.

Used for

• Pain
• Inflammation

What to know while taking it

It is taken with food, since the same prostaglandin block that eases pain also thins the stomach's protective lining, which is why the label warns about bleeding there. Prostaglandins also help the kidney manage salt, water and blood flow, so naproxen can move blood pressure and weaken lisinopril and furosemide, and creatinine and eGFR are worth following where kidney disease is already known. It is not combined with warfarin, because bleeding risks add together, nor with ibuprofen or diclofenac, which are the same kind of drug, so adding another brings risk rather than relief. Hemoglobin is tracked because blood loss from the stomach can be slow and silent.

When to see a doctor

Black or tarry stools, vomiting that looks like coffee grounds, or stomach pain that keeps coming back suggest bleeding and need a doctor promptly. The same goes for swelling of the ankles, a clear drop in how much urine is passed, or new breathlessness, paleness and fatigue.

Worth knowing

• Raises the risk of stomach bleeding
• Caution with kidney disease
• Can lower blood pressure

Markers to watch

• Creatinine
• eGFR
• Hemoglobin