How Does Naproxen Work? - MedicineHow

How Does Naproxen Work?

How Does Naproxen Work

Naproxen or naproxen sodium is a type of drug called a non-steroidal anti-inflammatory drug (NSAID). It works by stopping the production of compounds called prostaglandins in the body, which have a number of effects, including to cause inflammation.

As a result, naproxen can help to reduce pain and inflammation by stopping the production of prostaglandins. This is why it is usually used to relieve painful inflammatory conditions, such as arthritis. It is also commonly used to help relieve period pain in women.

Brand Names and Doses

Brand Names and Doses

Naproxen is the generic name of the drug, which is the name of the active component that has an effect on your body. You may also know it better by one of its brand names, which are the names given to the medication made by each pharmaceutical company. Brand names of naproxen include:

  • Inza tablets (250 mg, 500 mg)

  • Naprosyn tablets (250 mg, 500 mg)

  • Naprosyn oral liquid (25 mg/mL)

  • Naprosyn SR tablets (750 mg, 1000 mg)

  • Proxen SR tablets (750 mg, 1000 mg)

The SR in “Naprosyn SR” and “Proxen SR” means that the medication, slowly releases the drug over a longer period of time, known as controlled release. This means that you can take a dose once per day instead of twice per day, which is more convenient.

Naproxen sodium also contains naproxen (but sodium as well) and is available under the following brand names:

  • Aleve tablets (220 mg)

  • Naprofen tablets (275 mg)

  • Eazydayz tablets (275 mg)

  • Naprogesic tablets (275 mg)

  • Nurolasts tablets ( 275 mg)

  • Anaproc tablets (550 mg)

  • Crysanal tablets (550 mg)

It is best to take doses with or shortly after food to reduce the risk of side effects.

What type of drug is it?

Naproxen is a type of drug known as a non-steroidal anti-inflammatory drug (NSAID), which is a group of drugs that all work in a similar way. Other examples of NSAIDs include:

Naproxen is a nonselective NSAID, which means that it blocks both COX-1 and COX-2 to stop the production of more types of prostaglandins than some other NSAIDs. This means that it is more likely to cause side effects due to the action of the other prostaglandins that is reduced.

What is Naproxen used for?

Naproxen can be used to help relieve symptoms of pain and inflammation caused by a variety of health conditions such as:

  • Rheumatoid arthritis

  • Osteoarthritis

  • Ankylosing spondylitis

  • Period pain or heavy menstrual bleeding

  • Migraine

  • Muscular injury pain

How does it work?

Naproxen works by inhibiting COX-1 and COX-2, which are needed to produce the different prostaglandins in your body. You have many different types of prostaglandins in your body, and there are some in almost every tissue of your body. They each have different effects, such as to cause:

  • the tissues in your body to become inflamed

  • your blood vessels to relax and widen

  • the platelets in your blood to come together to form a clot

Naproxen has a general effect on almost all the prostaglandins because it blocks both COX-1 and COX-2 from producing prostaglandins in your body. This means that it can reduce all of the usual effects prostaglandins. We want it to reduce inflammation because that is why we are using it, but it can also cause hypertension and affect the way the blood forms clots.

Side Effects

There are many different side effects that you may experience if you are taking naproxen. These do not affect everyone, but it’s important to know what they are so that you can recognize them if you do notice them.

The side effects of naproxen may include:

  • Nausea​

  • Heartburn (dyspepsia)

  • Diarrhea

  • Headache

  • Dizziness

  • Gastrointestinal ulcers

  • Gastrointestinal bleeding

  • Hypertension

This is not a complete list of side effects, but just some of the most common. Please see the Naproxen information leaflet for more detailed information.

Drug Interactions

Naproxen can interact with many other medications when they are used in together, including:

  • ACE Inhibitors

  • Aldosterone antagonists

  • Alendronate

  • Amiloride

  • Aspirin

  • Beta blockers

  • Brimonidine

  • Calcineurin inhibitors

  • Corticosteroids

  • Cyclosporin

  • Fluconazole

  • Lithium

  • Loop diuretics

  • Methotrexate

  • Phenindione

  • Potassium

  • Prostaglandin analogues

  • Rifampicin

  • Sartans

  • Tacrolimus

  • Thiazide diuretics

  • Thiazolidinediones

  • Triamterene

  • Warfarin

These medications can often be used together, but your doctor should be aware that you are taking both medications so that they can adjust the dose as needed to ensure they are safe and effective.


There are some people who may need to avoid using Naproxen, or use it with caution, because they may be at risk of side effects due to the medication.

Peptic ulcers or GI bleeding:

Coagulation disorders:

Cardiovascular disease:


Inflammatory Bowel Disease (IBD):

Renal Impairment

Pregnancy and Breastfeeding

Naproxen is not usually recommended for women who are pregnant or trying to conceive. This is because it can interfere with fertility and the development of the fetus.

For women planning to become pregnant, it can prevent or delay ovulation, so that the woman is less likely to conceive. Additionally, using naproxen during pregnancy, particularly at the time of conception, is linked to a higher risk of miscarriage. It may also cause other problems later on in the pregnancy and should be avoided.

For women who are breastfeeding, naproxen is considered safe to use.

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How Does Naproxen Work?
About the author


Yolanda is a passionate medical writer who loves to help people understand how health and different treatments work. After graduating in Pharmacy in Australia, she moved to Italy to study the Mediterranean way of life and continue learning about health and medicine.


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