Naproxen controlled-release belongs to the class of medications called nonsteroidal anti-inflammatory drugs (NSAIDs). It is used to reduce the pain and swelling associated with rheumatoid arthritis and osteoarthritis. It works by reducing the amount of certain chemicals produced by your body that cause pain and swelling.

Naproxen controlled-release does not cure these conditions nor does it prevent these conditions from getting worse. This medication is not recommended for treatment of short-term pain. The full effects of this medication are usually seen within 1 or 2 weeks.

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.

The recommended starting dose of naproxen controlled-release is 750 mg taken once daily.

Your doctor may adjust your dose according to your response. The lowest dose needed to control pain and inflammation should be used.

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.

Naproxen controlled-release is best taken after a meal, or with food or milk. Do not lie down for about 15 minutes to 30 minutes after taking this medication. Swallow the tablets whole, and do not crush or chew them.

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 dose. 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 and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to naproxen or any ingredients of the medication
• are breast-feeding
• are in the third trimester of pregnancy (after 28 weeks of pregnancy)
• are under 18 years of age
• have a bleeding disorder
• have a history of asthma, itchy skin rash, or allergic reactions after taking ASA (acetylsalicylic acid) or other nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., ibuprofen, celecoxib, diclofenac, indomethacin)
• have active stomach bleeding such as gastric or duodenal ulcer, or have other types of bleeding from the stomach or intestines
• have bleeding in the brain
• have high blood potassium (hyperkalemia)
• have or have had inflammatory bowel disease (e.g., Crohn's disease or ulcerative colitis)
• have recently had heart bypass surgery
• have severe, uncontrolled heart failure
• have severely decreased liver function or active liver disease
• have severely decreased kidney function or worsening kidney disease

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
• changes in taste
• constipation
• diarrhea
• dizziness
• drowsiness
• headache
• heartburn
• gas
• increased thirst
• indigestion
• increased skin sensitivity to sun
• lightheadedness
• mouth sores
• nausea
• rash
• sweating
• upset stomach
• vomiting

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:

• blurred vision or any change in vision
• bruising
• burning, prickly, or numb sensations
• changes in hearing
• changes in menstrual periods
• confusion
• difficulty concentrating
• hair loss
• hearing problems, ringing in the ears
• nervousness
• persistent indigestion, nausea, stomach pain, or diarrhea
• spinning sensation
• signs of anemia (low red blood cells), e.g.:
• dizziness
• pale skin
• unusual tiredness or weakness
• shortness of breath
• signs of depression, e.g.:
• changes in sleep
• changes in weight
• decreased interest in activities
• poor concentration
• thoughts of suicide
• signs of increased blood pressure, e.g.:
• dizziness
• fainting
• fatigue
• chest pain
• signs of kidney problems, e.g.:
• increased urination at night
• decreased urine production
• blood in the urine
• change of urine colour
• signs of liver problems, e.g.:
• dark urine
• diarrhea
• loss of appetite
• nausea
• pale stools
• vomiting
• weight loss
• yellowing of the skin or whites of the eyes
• signs of urinary tract problems, e.g.:
• bladder pain
• bloody or cloudy urine
• change in urine colour or odour
• difficult, burning, or painful urination
• frequent urge to urinate
• loss of bladder control
• sudden large increase or decrease in the amount of urine
• swelling of the feet or lower legs
• symptoms of heart failure, e.g.:
• shortness of breath
• wheezing
• chest tightness
• fatigue
• cough
• fluid retention
• swelling in the ankles, legs, and feet

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

• signs of a serious allergic reaction, e.g.:
• abdominal cramps
• difficulty breathing
• nausea and vomiting
• swelling of the face and throat
• signs of a severe skin reaction, e.g.:
• a rash combined with fever or discomfort
• a rash covering a large area of the body
• a rash that spreads quickly
• blistering
• peeling
• signs of bleeding in the stomach, e.g.:
• bloody, black, or tarry stools
• spitting up blood
• vomiting blood or material that looks like coffee grounds
• signs of breathing problems, e.g.:
• fast or irregular breathing
• shortness of breath
• troubled breathing, wheezing, or tightness in chest
• signs of heart attack, e.g.:
• sudden chest pain or pain radiating to back, down arm, jaw
• sensation of fullness of the chest
• nausea
• vomiting
• sweating
• anxiety
• signs of heart problems, e.g.:
• chest pain
• difficulty breathing
• fast, irregular heartbeat or pulse
• signs of lung problems, e.g.:
• difficulty breathing with fever
• coughing
• wheezing
• breathlessness
• signs of meningitis not caused by infection (e.g., headache [severe], throbbing, or with stiff neck or back)
• signs of stroke, e.g.:
• sudden or severe headache
• sudden loss of coordination
• vision changes
• sudden slurring of speech or unexplained weakness, numbness, or pain in arm or leg

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.

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 use this medication.

Allergy: Some people who are allergic to other NSAIDs or ASA also experience allergic reactions to naproxen controlled-release. Before you take naproxen controlled-release, inform your doctor about any previous adverse reactions you have had to medications, especially NSAIDs. People who have experienced difficulty breathing after taking ASA or other NSAIDs should not take naproxen controlled-release.

Contact your doctor at once if you experience signs of an allergic reaction, such as skin rash, itching, difficulty breathing, or swelling of the face and throat.

Anemia: This medication may cause anemia (low red blood cells). If you take this medication for a long period of time, your doctor will periodically monitor your red blood cell levels. If you experience symptoms of anemia (e.g., shortness of breath, fatigue, pallor, fast heartbeat), contact your doctor as soon as possible.

Asthma: People with asthma are at increased risk of severe and even fatal allergic reactions (anaphylaxis) when taking this medication. People with asthma or other breathing problems should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

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.

Bleeding disorders: Naproxen controlled-release may increase bruising and bleeding from cuts may take longer to stop. People with bleeding disorders, a history of bleeding problems, or those who are taking medications to prevent clotting, should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Blood pressure: Naproxen controlled-release may cause an increase in blood pressure, even when there have been no blood pressure problems in the past. People with high blood pressure should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication and whether any special monitoring is needed. Report any ongoing increase in blood pressure to your doctor as soon as possible.

Drowsiness/reduced alertness: This medication may cause drowsiness. Do not drive, operate machinery, or perform other potentially hazardous tasks until you have determined how this medication affects you.

Fluid and electrolyte balance: This medication can cause fluid retention and edema. People with conditions that might be affected by fluid retention or contribute to fluid retention (e.g., congestive heart failure, high blood pressure, kidney disease, or reduced kidney function) should be closely monitored by their doctor while taking this medication.

This medication may cause high blood potassium levels. People most at risk are seniors; people with conditions such as diabetes or kidney failure; and those taking beta-adrenergic blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin-II receptor antagonists, cyclosporine, or some diuretics (water pills).

Heart problems: Naproxen controlled-release may increase the risk of heart-related problems such as heart attack, stroke, or blood clots. The risk may increase with the length of treatment and for people who already have heart disease (e.g., a history of heart attack or angina, stroke, transient ischemic attacks, or congestive heart failure), or risk factors for heart disease (e.g., high blood pressure, high cholesterol, diabetes, smoking, impaired kidney function). Talk to your doctor about the risks and benefits of using this medication. To minimize heart-related problems, the lowest dose of naproxen controlled-release should be used for the shortest time possible.

Infection: This medication may mask the signs of infection (e.g., fever). If you notice other symptoms of infection (e.g., painful or frequent urination, productive cough) contact your doctor.

Kidney function: Long-term use of naproxen controlled-release may increase the risk of developing reduced kidney function. This risk is increased for people who already have kidney disease, liver disease, or heart failure; for people who are taking certain medications (e.g., beta-adrenergic blockers, angiotensin converting enzyme [ACE] inhibitors, angiotensin-II receptor antagonists, cyclosporine, or some diuretics [water pills]; and for seniors. Your doctor will monitor your kidney function with blood tests during long-term therapy with naproxen controlled-release.

Liver function: Rarely, this medication can cause decreased liver function. If you experience yellowing of the skin or whites of the eyes, nausea, vomiting, or loss of appetite, contact your doctor immediately. If you take this medication for a long period of time, your doctor will periodically check your liver function with blood tests.

Stomach problems: Stomach or duodenal ulcers, perforation, and bleeding from the stomach have occurred with this medication. These complications can occur at any time. The risk for ulcers and bleeding increases with higher doses and longer treatment periods. The risk also increases for people with a history of ulcers, for people who smoke or drink large amounts of alcohol, or for people taking certain medications (e.g., warfarin, ASA, clopidogrel, prednisone, citalopram, fluoxetine, paroxetine, sertraline). Stop taking this medication and contact your doctor immediately if you experience symptoms of stomach ulcers or bleeding in the stomach (e.g., bloody or black, tarry stools).

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.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Use of this medication at 20 weeks or later in pregnancy may increase the risk of kidney damage and complications due to low amniotic fluid in the developing baby. When naproxen controlled-release is taken during the last 3 months of pregnancy, there is an increased risk of the child developing heart problems and the mother having a longer labour to deliver the baby.

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

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and are taking naproxen controlled-release, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: Naproxen controlled-release is not recommended for children under the age of 18 years. The safety and effectiveness of using this medication have not been established for children.

Seniors: Seniors appear to have a higher risk of side effects, such as bleeding and kidney problems. They should use the lowest effective dosage for the shortest time period possible.

There may be an interaction between naproxen controlled-release and any of the following:

• acetylsalicylic acid (ASA)
• alcohol
• aliskiren
• aminoglycoside antibiotics (e.g., amikacin, gentamicin, tobramycin)
• anagrelide
• angiotensin-II receptor blockers (ARBs; e.g., candesartan, irbesartan, losartan)
• angiotensin-converting enzyme inhibitors (ACEIs; e.g., ramipril, enalapril, lisinopril)
• antacids
• apixaban
• beta-blockers (e.g., propranolol, atenolol)
• bimatoprost
• bismuth subsalicylate
• bisphosphonates (e.g., alendronate, risedronate)
• caplacizumab
• cholestyramine
• clopidogrel
• colesevelam
• colestipol
• corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
• cyclosporine
• dabigatran
• deferasirox
• deoxycholic acid
• desmopressin
• digoxin
• dipyridamole
• diuretics (water pills; e.g., furosemide, hydrochlorothiazide, spironolactone)
• drospirenone
• edoxaban
• 5-ASA derivatives (e.g., sulfasalazine, mesalazine)
• heparin
• herbal medications (e.g., garlic, ginger, ginkgo, ginseng)
• hydralazine
• icosapent ethyl
• latanoprost
• lithium
• low molecular weight heparins (e.g., dalteparin, enoxaparin, tinzaparin)
• metformin
• methotrexate
• multivitamins
• obinutuzumab
• omega-3 fatty acids
• other nonsteroidal anti-inflammatories (NSAIDs; e.g., diclofenac, ibuprofen, ketorolac, celecoxib)
• pentoxifylline
• potassium supplements
• prasugrel
• protein kinase inhibitors (e.g., dasatinib, ibrutinib)
• quinolone antibiotics (e.g., ciprofloxacin, norfloxacin, ofloxacin)
• rivaroxaban
• selective serotonin reuptake inhibitors (SSRIs; e.g., paroxetine, fluoxetine, citalopram, sertraline)
• serotonin-norepinephrine reuptake inhibitors (SNRIs; desvenlafaxine, duloxetine, venlafaxine)
• sodium phosphates
• sucralfate
• tacrolimus
• tenofovir
• ticagrelor
• tipranavir
• tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
• vaccines
• vitamin E
• 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.