Swelling of the hands, arms, feet, ankles, or lower legs; Anemia (red blood cells do not bring enough oxygen to all parts of the body); Or click here liver or kidney disease. Tell your doctor if you are pregnant, especially if you are in the last few months of your pregnancy, you plan to become pregnant, or you are breast-feeding. If you become pregnant while taking naproxen, call your doctor. Talk to your doctor about the risks and benefits of taking naproxen if you are 65 years of age or older. Older adults should usually take lower doses of naproxen for short periods of time because higher doses used regularly may not be more effective and are more likely to cause serious side effects. If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking naproxen.