It is very important that your doctor check your progress at regular visits while you are taking this medicine. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood, urine, and other laboratory tests may be needed to check for unwanted effects.
Naproxen may increase your risk of having a heart attack or stroke. This is more likely in people who already have heart disease. People who use this medicine for a long time might also have a higher risk.
Naproxen may cause bleeding in your stomach or intestines. This problem can happen without warning signs. This is more likely if you have had a stomach ulcer in the past, if you smoke or drink alcohol regularly, if you are over 60 years of age, are in poor health, or are using certain other medicines (such as steroids or a blood thinner).
This medicine may cause a serious type of allergic reaction called anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash; itching; hoarseness; trouble breathing; trouble swallowing; or any swelling of your hands, face, or mouth while you are using this medicine.
Serious skin reactions can occur with this medicine. Check with your doctor right away if you have any of the following symptoms while using this medicine: blistering, peeling, or loosening of the skin; chills; cough; diarrhea; fever; itching; joint or muscle pain; red skin lesions; sore throat; sores, ulcers, or white spots in the mouth or on the lips; or unusual tiredness or weakness.
Using this medicine during late pregnancy can harm your unborn baby. If you think you have become pregnant while using this medicine, tell your doctor right away.
Check with your doctor right away if you have any symptoms of liver problems including dark-colored urine or pale stools, nausea, vomiting, loss of appetite, pain in your upper stomach, or yellowing of your skin or eyes.
This medicine may cause hypomagnesemia (low magnesium in the blood). Your doctor may want to check your blood levels if you are taking this medicine for more than one year, or if you are taking this medicine together with digoxin (Lanoxin®) or certain diuretics or "water pills". Stop using this medicine and check with your doctor right away if you have convulsions (seizures); fast, racing, or uneven heartbeat; muscle spasms (tetany); tremors; or unusual tiredness or weakness.
Check with your doctor right away if you have watery stool that does not go away, stomach pain, and fever while taking this medicine.
Do not stop taking this medicine without first checking with your doctor, or unless told to do so by your doctor.
Before having any kind of surgery or medical tests, tell your doctor that you are using this medicine. It may be necessary for you to stop the medicine for a while, or to change to a different medicine before your procedure.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.