Fenoprofen (oral)


Fenoprofen, like other NSAIDs, works by reducing the production levels of prostaglandins. Prostaglandins are the enzymes responsible for the development of pain, fever and swelling symptoms that accompany inflammation in your body. Because fenoprofen works in this way, it is often included in treatment plans for patients with osteoarthritis or rheumatoid arthritis.

Doctors will also prescribe it on an as-needed basis to treat fever, swelling and mild to moderate pain symptoms from any of a variety of other medical conditions.

Brand Names:

  • Nalfon

Conditions Treated

  • Fever, swelling and mild to moderate pain from various medical conditions

Type(s) of Medication

  • Nonsteroidal anti-inflammatory drug

Side Effects

While side effects are not common when taking fenoprofen, there are some adverse reactions that can occur from the use of this medication. Some of the side effects that can occur with use of fenoprofen may not need medical attention, as they typically subside once your body has adjusted to the medication. This process can take anywhere from one to several weeks. If you have any questions or concerns about any of these milder side effects, or if they continue or are bothersome, check with your doctor. They should be able to answer your questions, address your concerns and recommend ways to either prevent or reduce the severity of these effects.

A list of lesser side effects includes:

  • Stomach issues, including discomfort, acid or sour stomach, belching and constipation

Other, less common side effects in this category that do not require immediate medical attention are body aches and pain, coughing, ear congestion, sneezing, stuffy/runny nose, increased sweating, loss of voice, changes to your mood or mental processes, muscle aches, tremors and trouble sleeping.

While some side effects are less serious and can be resolved with a quick conversation with a medical professional, others are more serious and will require you to talk to your doctor or seek medical intervention immediately if they start happening. A list of these side effects includes:

  • Pain in the stomach or abdomen

A very rare, but serious, side effect of taking fenoprofen is liver disease, which can be fatal. Stop taking fenoprofen immediately and talk to your doctor right away if you have any of the following symptoms:

  • Eyes or skin turning yellow

While serious allergic reactions to this medicine (referred to as anaphylaxis) are highly unlikely, you should call for emergency medical services if you notice any of the following symptoms after taking this drug:

  • A rash


Actual dosages for fenoprofen, like for any drug, will vary and depend on a number of factors. These factors include the medical condition the medicine is being prescribed for, your age, other medical conditions you may have and other medications your doctor has you taking to treat those conditions.

While the manufacturer has created a set of general recommendations for how often and how much of this medication to take, the best thing you can do is to follow the instructions given by your doctor for taking them. The manufacturer may know what conditions their medication is used to treat, but your doctor is the one who knows you and your health condition and is the best person to determine your course of treatment.

The typical dose of fenoprofen for an adult as part of treatment for osteoarthritis or rheumatoid arthritis is 400 mg to 600 mg taken orally either three or four times a day, with a maximum amount of 3,200 mg per day. Your doctor will determine which dosage is best for you and will likely adjust it over time in order to make sure it is the lowest dosage that is effective. Patients with osteoarthritis tend to need smaller doses than patients with rheumatoid arthritis and are more likely to be started on the lower end of the recommended dosage.

For relief of mild to moderate levels of pain on an as-needed basis, 200 mg of fenoprofen should be taken orally every four to six hours on an as-needed basis. If you are taking it on an as-needed basis, then do so at the first signs of pain. Fenoprofen, and other pain medications, might not work as well as intended if you wait until the pain has worsened significantly to take it.

It is recommended that you take this medicine with a full (eight ounce) cup of water. If you experience an upset stomach while taking it, then take it with food, milk or an antacid. If you intend to lie down after taking a dose, wait until at least ten minutes have passed after taking to do so, as adverse reactions can occur.

When you take this medication, do not chew it, crush it, break it or otherwise divide it before taking, as this can lessen its overall effectiveness. Swallow the pill whole.

Fenoprofen is not recommended for children under the age of eighteen, as the safety and effectiveness of medicine in this younger group of patients has yet to be established. If your doctor determines this medication is to be administered to your child, then they will need to determine the usage and necessary dosage of the medication. Do not give this medication to your child unless a doctor has prescribed it for them.

Do not take more or less than your prescribed dosages, and do not take it more frequently than the prescription states. Also, do not use more than the maximum amount of 3,200 mg in any 24 hour time period, and do not take it for any longer than your doctor directs you to. If you have any questions about this medication, how to take it or possible interactions, discuss them with a medical professional.

If you miss the normal time for a dose of fenoprofen, take it as soon as possible afterwards. If you remember close to the time for your next dose, skip the missed one and take your next dose at its scheduled time. Do not double up on doses of this medication in order to catch up to your regular schedule, as some serious side effects can happen if you do this often.

When taken for osteoarthritis or rheumatoid arthritis, fenoprofen will typically reduce the pain and swelling symptoms of these conditions as early as a week after starting treatment, but can take as much as two or three weeks to start working and several weeks to become fully effective. If there is no symptom reduction or if your condition worsens during that time period, consult with your doctor. There may be other treatment options that work better or more effectively for your condition.

Types of Interactions

Fever, swelling and pain can prevent sleep and make it difficult for a person to function in a normal capacity. The manufacturer's intention in creating fenoprofen was to help people with these symptoms be able to do the things they need to do and the things they love to do, whether the cause be arthritis or other medical conditions.

However, as is the case with many medications, what fenoprofen does inside of your body often changes once it interacts with other prescribed medications, over the counter drugs or supplements you might be taking. It can also interact with substances you consume or other medical conditions you may have in ways that make it less effective.

For these reasons, it is necessary to have a candid discussion with your doctor about all of your medical conditions and which prescriptions and supplements you might be using before you start taking fenoprofen.

Drug Interactions:

There is a long list of drugs and medications that can have interactions with fenoprofen, with some interactions being more serious than others. Talk to your doctor about any other medicines (prescription or over the counter) or supplements you are taking. A list of common medications and supplements that can interact with fenoprofen includes:

  • Antipsychotic medications, like aripiprazole

Food and Drug Interactions:

Fenoprofen and alcohol are known to have potentially dangerous interactions, so avoid drinking while you are taking this medication.

Medical Interactions:

Besides the potential interactions with other drugs and drink, there are a few medical conditions that could have a negative interaction with fenoprofen, like fluid retention or edema. These conditions include:

  • Preexisting fluid retention

Note that these lists of interactions are not exhaustive and the list of potential interactions is long. Remember that you should always talk to your doctor or pharmacist if you are concerned about the possibility that a medical condition you have, something you are consuming or the medications you are taking could interfere with the intended effects of fenoprofen. It is better to address these concerns sooner rather than later.


If you are allergic to fenoprofen, aspirin, or other non-steroidal anti-inflammatory drugs, like ibuprofen, naproxen, or celecoxib, tell your doctor or pharmacist before taking this medicine, as it may have inactive ingredients that can cause serious allergic reactions and other potential problems.

Do not take fenoprofen if you have medical conditions like severe kidney disease, aspirin-sensitive asthma or if you have recently undergone heart bypass surgery.

Tell your doctor if you have a medical history of renal disease, liver disease, diabetes, stomach, intestinal or esophagus problems, heart disease, high blood pressure, stroke, blood disorders, clotting or bleeding issues, asthma or nasal polyps.

Some kidney problems have been known to occur with the use of fenoprofen and other non-steroidal anti-inflammatory medications. If you are older, have become dehydrated, have kidney disease or heart failure or use certain medications, the risk of these problems increases. Be sure to drink extra fluids, as directed by your doctor. If you see any change in urine amounts, talk to your doctor immediately, as this can be an indication of problems occurring.

You should be careful if you are taking lithium as part of a treatment for bipolar disorder, as fenoprofen can increase the level of lithium in your blood to be at toxic levels.

Do not drink alcohol while taking fenoprofen, as it can increase the risk of stomach bleeding.

Use caution when taking fenoprofen if you have ulcers or other stomach or intestinal conditions, as larger doses of this medication can cause gastrointestinal bleeding or ulcers to occur.

You may also want to avoid fenoprofen if you are taking certain blood pressure medications, as it can raise your blood pressure and reduce the effectiveness of those medications. Check your blood pressure regularly, and let your doctor know if the results are high.

You should not take fenoprofen if you are taking oral blood thinners or anticoagulants, such as warfarin.

Fenoprofen can make you drowsy or dizzy, so do not attempt to drive, operate machinery or do anything else that requires you to be alert until you know that you can do so safely. Talk to your doctor if you are using marijuana, as it can increase dizziness or drowsiness that might already be occurring.

You may become more sensitive to sunlight while taking this medication, so limit your time in the sun and avoid using tanning booths or sunlamps. When you are outdoors, wear protective clothing and use sunscreen. Let your doctor know immediately if you get sunburned or experience skin blisters or redness.

It is recommended that you do not take this medication if you are a woman who is trying to become pregnant, as there may be female fertility impairments that come along with its use. If you are pregnant and in your second trimester, discuss use of this medicine with your doctor. It is not recommended for use while you are in your first trimester, as there is an increased risk of com/health/miscarriage/">miscarriage and the potential for serious malformations during this time period. It is also recommended that you avoid use during the third trimester, as there are concerns it may do harm to your unborn baby and it has the potential to interfere with the delivery of your baby.

Discuss the use of fenoprofen with your doctor if you are currently breastfeeding and have concerns about taking it during that time. Currently, there is not enough published data to determine how much of the drug can be passed on to your baby while you are nursing.

If you have a medical procedure or testing coming up and are taking fenoprofen, talk to your doctor. Depending on the testing or procedure, you may need to switch to a different NSAID prior or stop treatment beforehand.

Do not take any other medicines - prescription, over the counter or herbal or vitamin supplements - unless you have discussed the use of them with your doctor, as there is the potential for interactions that decrease the effectiveness of fenoprofen.


The manufacturer recommends that you store fenoprofen in a room that consistently stays at room temperature (between 68-77 degrees Fahrenheit or 20-25 degrees Celsius). Store this medicine in tightly closed containers, away from sources of heat (like a stove or heater), moisture (like sinks or showers) and direct sunlight (like windows). Keep the medication in a place that is safely out of the reach of children and pets.

Do not hold onto doses of fenoprofen that are past their use by date. While you might think holding onto excess medication once you finish treatment is a good plan, it is exactly the opposite that is true. The best plan is to dispose of the medication once your course of treatment is complete, your doctor has had you stop taking it or the medication has reached its expiration date.

As with most other medications, you should check with your doctor, pharmacist or local waste disposal company about how to safely dispose of fenoprofen once it is expired or your doctor no longer has you taking it as a part of treatment for your medical condition. Do not flush this medicine down the toilet unless instructed to do so.


Fenoprofen is one of a number of nonsteroidal pain medications that can be prescribed for fever, inflammation and pain symptoms that are the result of a wide variety of medical conditions. In the case of osteoarthritis and rheumatoid arthritis, this drug is often effectively used as part of a treatment plan that eases joint pain and reduces swelling.

While the medication can be greatly beneficial in relieving these symptoms, there are risks associated with taking it that can only be determined by a doctor. This can only be determined by a doctor if their patient is honest with them about all of their medical conditions. Patients need to be willing to have conversations with their doctors about everything from their medical history and as much as they know about their family's medical history, to their current medical condition and daily habits.

It is always in the best interest of any patient, no matter what their medical condition, to disclose their medical history, as well as their concerns, to their doctor before taking fenoprofen (or any other medication). When it comes to fenoprofen, the list of possible drug interactions that can make it more dangerous to be taken is long. There are also interactions with food, drinks and other medical conditions that should be discussed with your health care professional, in order to make sure this medicine is able to work as effectively as possible.

The impact of these interactions can be lessened or even eliminated if your doctor is aware of the possibility and knows they need to find a way around it. This may be possible with a change in dosage of fenoprofen, a change in dosage of other medications you are taking or changing medications completely, but can only be done if the doctor knows it needs to be done.

When the correct levels are prescribed and the medicine is taken as directed, fenoprofen can greatly aid in the relief of fevers, pain and swelling. For patients with arthritis, the mitigation of these symptoms enables them to better perform the non-medication parts of their treatment that lessen the severity of their condition and enjoy a quality of life that they could not have imagined previously.