How does this medication work? What will it do for me?

Naproxen sodium belongs to a group of medications called nonsteroidal anti-inflammatory drugs (NSAIDs). It reduces swelling, inflammation and pain, and is used for the relief of mild to moderately severe pain accompanied by inflammation.

Naproxen sodium is used to help relieve pain due to muscle injury, (e.g., bone, muscle, tendon, cartilage, ligament), dental extraction, menstrual cramps, and cramping after childbirth. It is believed to work by stopping the production of prostaglandins, which cause pain and swelling.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Anaprox
Each oval-shaped, light blue, film-coated tablet, "NPS-275" engraved on one side, contains naproxen sodium 275 mg. Nonmedicinal ingredients: indigotine aluminum lake, hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, povidone, talc, and titanium dioxide.

Anaprox DS
Each oblong, blue, film-coated tablet, "NPS 550" engraved on one side, contains naproxen sodium 550 mg. Nonmedicinal ingredients: hydroxypropyl methylcellulose, indigotine aluminum lake, magnesium stearate, microcrystalline cellulose, polyethylene glycol, povidone, talc, and titanium dioxide.

How should I use this medication?

The recommended adult starting dose of naproxen sodium is 550 mg (two 275 mg tablets) followed by one 275 mg tablet every 6 to 8 hours as needed.

Alternatively, one of the 550 mg tablets may be taken twice daily. Do not take more than 1,375 mg per day. The lowest dose for the shortest period of time should be used to reduce the risk of side effects.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to naproxen sodium or any ingredients of this medication
  • are allergic to ASA or other NSAIDs (e.g., ibuprofen, ketorolac, diclofenac) or have had allergic symptoms (e.g., runny nose, asthma, itchy skin rash, nasal polyps, swelling of the face, throat, or tongue) caused by these medications
  • are 18 years of age or younger
  • are breast-feeding
  • are currently taking other NSAIDs (e.g., ibuprofen, ketorolac, indomethacin)
  • are going to have or have just had heart bypass surgery
  • are in your third trimester (last 3 months) of pregnancy
  • have a bleeding disorder
  • have a bleeding ulcer in the stomach or intestines
  • have bleeding in the brain
  • have high levels of blood potassium (hyperkalemia)
  • have inflammatory bowel disease (e.g., ulcerative colitis, Crohn's disease)
  • have severely reduced liver function or liver disease
  • have severely reduced or worsening kidney function
  • have severe, uncontrolled heart failure
  • have recently had coronary artery bypass surgery

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • abdominal pain
  • constipation
  • diarrhea
  • drowsiness
  • heartburn, indigestion
  • increased sweating
  • irritation, dryness, or soreness of mouth
  • nausea

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • bladder pain
  • confusion
  • decreased hearing, any other change in hearing, or ringing or buzzing in ears
  • difficult or painful urination
  • dizziness or lightheadedness
  • feeling of being unwell
  • feeling thirsty
  • headache
  • increased sensitivity of the skin to sunlight (sunburn, skin blisters, skin rash, redness, itching, discoloration)
  • loss of appetite
  • persistent heartburn, stomach pain, diarrhea, or nausea
  • pounding heartbeat
  • rapid weight gain
  • stiff neck
  • swelling of the feet or ankles
  • symptoms of depression (difficulty concentrating, trouble sleeping or sleeping too much, increase or decrease in appetite, loss of energy, feeling of guilt or hopelessness, loss of interest in activities)
  • symptoms of liver problems (e.g., yellowing of the skin or eyes with or without itchy skin)
  • tiny pinpoint red spots on the skin
  • unusual bleeding or bruising
  • unusual tiredness or weakness without any other symptoms
  • vomiting

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • bloody or black, tarry stools
  • blurred vision or any visual disturbance
  • change in the amount or colour of urine
  • chills, fever, muscle aches or pains along with a skin rash
  • peeling or blistering skin
  • symptoms of a severe allergic reaction, e.g.:
    • hives
    • shortness of breath
    • swelling of the face, mouth, throat, or tongue
    • trouble breathing or chest tightness
    • wheezing
  • shortness of breath, wheezing, and chest tightness
  • vomiting of blood or material that looks like coffee grounds
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take this medication.

Allergic reactions: If you have had a reaction to acetylsalicylic acid (ASA) or other NSAIDs (e.g., ibuprofen, ketoprofen, ketorolac) that included a runny nose, itchy skin rash, nasal polyps, or shortness of breath and wheezing, you should not take this medication. If you experience symptoms of a severe allergic reaction (e.g., hives; difficulty breathing; wheezing; swelling of the face, tongue, or throat), get immediate medical attention.

Aseptic meningitis: This medication can rarely cause symptoms of aseptic meningitis (inflammation or swelling of the membranes around the brain and spinal cord that is not caused by bacteria). If you have an autoimmune condition (e.g., systemic lupus erythematosus, mixed connective tissue disease), you are more at risk for developing this. If you experience symptoms such as stiff neck, severe headache, nausea, vomiting, fever, or changes in consciousness, stop taking this medication can get immediate medical attention.

Bladder problems: This medication may cause bladder pain, painful or difficult urination, or increased frequency of urination. If these symptoms occur without an explanation (e.g., infection), stop taking this medication and contact your doctor.

Blood clotting: This medication may reduce the ability of the blood to clot. If you are taking anticoagulants (e.g., warfarin, heparin) or have hemophilia or other blood disorders (e.g., low platelets), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you have a bleeding disorder, do not take this medication.

Drowsiness/reduced alertness: As with other NSAIDs, naproxen sodium can cause drowsiness, dizziness, and blurred vision. Avoid driving and other activities that require alertness and concentration until you determine the effect this medication has on you.

Fluid and electrolyte balance: NSAIDs such as naproxen sodium can cause fluid retention and edema (swelling). This can lead to high blood pressure or worsening of heart failure. If you have heart failure or high blood pressure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you have severe, uncontrolled heart failure, you should not take this medication.

Naproxen sodium may also cause high blood potassium levels. If you are a senior; have diabetes or kidney failure; or are taking beta-blockers (e.g., metoprolol, atenolol), angiotensin converting enzyme (ACE) inhibitors (e.g., ramipril, enalapril), or some diuretics (e.g., triamterene, amiloride), you are more at risk of high blood potassium. If you have high blood potassium levels, you should not take this medication.

Heart attack and stroke: This medication may be associated with an increased risk of heart attack and stroke. The risk is increased with higher total daily doses and taking the medication over long periods of time. If you have a history of heart disease (e.g., heart attack, stroke, heart failure) or have risk factors for heart disease (e.g., high blood pressure, high cholesterol, diabetes, smoking, kidney disease) discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Kidney function: Long-term use of naproxen sodium may lead to kidney problems. If you have kidney problems, liver disease, or heart failure; or are dehydrated, on a salt restricted diet, or are a senior, you have an increased risk for kidney problems while taking this medication. If you are taking medications such as diuretics (e.g., hydrochlorothiazide, triamterene, indapamide), ACE inhibitors (e.g., enalapril, ramipril), angiotensin receptor blockers (e.g., valsartan, candesartan), or cyclosporine, you are also at an increased risk.

If you have these conditions or are taking these medications, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you have severe kidney problems, you should not take this medication.

Liver problems: Rarely, this medication causes liver problems. If you have reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience unexplained tiredness, loss of appetite, itchy skin, or yellowing of the skin or eyes while taking this medication, contact your doctor immediately. If you have liver disease or severely reduced liver function, you should not take this medication.

Skin reactions: This medication can cause skin reactions, some of which may be severe. If you experience a skin rash, especially where the skin is blistering or peeling, stop taking this medication and contact your doctor.

This medication may make your skin more sensitive to sunlight (including sunlamps) and may cause sunburn, skin blisters, and skin redness, itching or discolouration. If you have a reaction from the sun while taking this medication, contact your doctor.

Ulcers or bleeding in the stomach or intestines: Naproxen sodium can cause stomach ulcers, perforation (holes), and bleeding from the stomach. These complications can occur at any time without warning and are sometimes severe enough to require immediate medical attention.

The risk of ulcers and bleeding are increased if you are taking higher doses of this medication for longer periods of time. Other factors that increase the risk of these complications include drinking excessive amounts of alcohol, increased age, smoking, poor health, H pylori infection, and taking certain medications (e.g., warfarin, ASA, clopidogrel, prednisone, citalopram, fluoxetine, paroxetine, sertraline).

If you currently have ulcers in the stomach or intestines that are bleeding, or have an inflammatory bowel disease (e.g., Crohn's disease, ulcerative colitis), you should not take this medication. If you have a history of these conditions, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Stop taking the medication and get immediate medical attention if you experience symptoms or signs of stomach ulcers or bleeding in the stomach (black and tarry stools, vomit that looks like coffee grounds, stomach pain). These reactions can occur at any time during treatment without warning.

Pregnancy: This medication should not be used during the third trimester (last 3 months) of pregnancy. This medication should not be used during the first and second trimester (first 6 months) of pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

This medication may reduce your ability to become pregnant. Taking this medication while trying to become pregnant is not recommended.

Breast-feeding: You should not use this medication if you are breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

Seniors: If you are a senior, you may have a higher risk of experiencing side effects from this medication. You should use the lowest effective dose under close medical supervision.

What other drugs could interact with this medication?

There may be an interaction between naproxen sodium and any of the following:

  • acetylsalicylic acid (ASA)
  • alcohol
  • angiotensin converting enzyme (ACE) inhibitors (e.g., ramipril, enalapril)
  • angiotensin receptor blockers (e.g., valsartan, candesartan, losartan)
  • antacids
  • beta blockers (e.g., metoprolol, atenolol)
  • cholestyramine
  • clopidogrel
  • colestipol
  • corticosteroids (e.g., prednisone)
  • cyclosporine
  • digoxin
  • diuretics (e.g., spironolactone, triamterene, furosemide, hydrochlorothiazide)
  • heparin
  • herbal products that affect blood clotting (e.g., cat's claw, chamomile, fenugreek, evening primrose, feverfew, garlic, ginger, ginseng, turmeric)
  • lithium
  • methotrexate
  • oral hypoglycemics (e.g., glyburide, gliclazide)
  • other NSAIDs (e.g., ketorolac, ibuprofen, diclofenac)
  • pemetrexed
  • phenytoin
  • potassium supplements
  • probenecid
  • SSRIs (e.g. citalopram, fluoxetine, paroxetine, sertraline)
  • sulfonamides (e.g., sulfamethoxazole)
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.