Leflunomide (Oral)


Rheumatoid arthritis is a chronic, incurable condition that is classified as an autoimmune disease. Patients with rheumatoid arthritis have pain and swelling in their joints, caused by inflammation in the joints. In the most basic explanation for this disease, it is caused by the body attacking its own joints. Over time, rheumatoid arthritis can distort the hands and wrists or other joints, rendering them debilitated.

While NSAID pain relievers are often prescribed for the pain associated with rheumatoid arthritis, disease modifying anti-rheumatic classifications of drugs, referred to as DMARDs, may also be prescribed to lessen the progression of the disease.

Leflunomide is one such DMARD classified drug, which is sold in the United States under the name Arava. Typically prescribed in patients with moderate to severe symptoms, Leflunomide is a prodrug, which means that it is not active until metabolized by the body. This medication regulates the production of an autoimmune produced enzyme known as a lymphocyte. By regulating the production of this enzyme, Leflunomide slows down the rheumatoid arthritis symptoms that are affecting the joints. Patients should experience relief of their inflammation and less pain and redness symptoms.

Off-label use of the drug includes cancer treatment, due to Leflunomide's properties of DNA cellular repair functionality. Leflunomide may also be used to treat other diseases such as Crohn's disease and for the prevention of rejection after organ transplants.

Leflunomide is known to suppress the immune system and patients are cautioned to avoid live vaccinations while they are being treated with this drug and also to avoid people who have colds, flu or other infections.

Conditions Treated

Type Of Medication

  • Pyrimidine synthesis inhibitor

Side Effects

By inhibiting an important enzyme in the body at the cellular level to stop rheumatoid arthritis symptoms, Leflunomide may also cause other effects on health that are unwanted and severe. Notify your physician right away if you have any of these symptoms:

  • Urine that is cloudy or bloody
  • Coughing
  • Difficulty breathing
  • Pain when breathing
  • Difficulty urinating or burning, painful sensation
  • Dizziness
  • Fever
  • Urination is more frequent or more in amount
  • Headache
  • Little to no appetite
  • Vomiting
  • Nausea
  • Sneezing
  • Throat soreness
  • Chest tightness
  • Yellow skin or eyes
  • Burning sensation in stomach or chest
  • Tingling, prickling or burning in toes or fingers
  • Pain in chest area
  • Diarrhea
  • Rapid, strong heart rhythm
  • Upset stomach
  • Stiff, painful muscles or joints
  • Severe pain in stomach
  • Fatigue
  • Weak muscles
  • Skin rash in a condensed area
  • Stools are black or tar-like
  • Gums bleed
  • Loose, blistered or peeling skin
  • Bloated feeling
  • Stools with signs of blood
  • Painful, numb, tingling or burning sensation
  • Chills
  • Stools are clay in color
  • Confused demeanor
  • Constipation
  • Vomiting continuously
  • Urine is dark
  • Fainting
  • Elevated body temperature
  • Chills
  • Overall fatigue or weak feeling
  • Hives on sex organs, hands, feet, legs, hands, throat, eyes, face, lips or tongue
  • Stools are light colored
  • Lightheaded
  • Pain in side or back
  • Abdominal pain that spreads to back or side
  • Skin paleness
  • Tiny red dots on skin
  • Breathing is fast, shallow
  • Lesions on this skin with purple middle sections
  • Bloodshot, irritated eyes
  • Ulcerated white spots on lips or mouth
  • Glandular swelling
  • Bruising or bleeding that is unexpected
  • Halitosis
  • Awkward, unsteady demeanor
  • Pain in stomach or upper right abdominal area
  • Vomiting blood
  • Weak hands, feet, arms or legs

Other symptoms may happen that don't require medical attention but could benefit from the advice given to you by your physician in order to ease them as your body gets accustomed to the medication. Seek advice from your medical professional if you have the following symptoms:

  • Pain in back
  • Loss of hair
  • Acid reflux or heartburn
  • Rash on skin
  • Pain in stomach
  • Unexpected loss of weight
  • Acne on skin
  • Anxious demeanor
  • Losing appetite
  • Mouth dryness
  • Gas
  • Mouth irritation or soreness
  • Skin itches or burns
  • Throat burns or is painful
  • Runny nose

If you have other changes to your health or mood that occur after you begin taking Leflunomide on a regular basis, let your doctor know right away to prevent any unwanted health issues.


Leflunomide should be taken exactly as your doctor has instructed for your prescribed dosage. Do not increase the amount of the medication you take or the frequency, thinking this will have a greater effect on your condition. This is not so and could, in fact, cause you harmful effects on your health. Do not take Leflunomide after your prescribed treatment time is over or if your doctor has determined it is not the correct medication for you.

Your dosage may be different from the general information provided here; always follow what your doctor has prescribed for you.

Adults who are considered low-risk for liver and bone marrow diseases will initially be prescribed a 100-milligram dose to be taken once daily for three days. The prescribed amount will then change to 20 milligrams once per day but may be adjusted further as determined by your physician.

Adult patients who are at a high risk of developing liver and bone marrow diseases due to the effects of Leflunomide on their systems will typically start on 20 milligrams of this medication to be taken once daily and adjusted by their physician as required.

Dosage size, frequency and duration of Leflunomide in pediatric patients are up to the attending physician in each case if determined to be appropriate.

Missing a dose of Leflunomide is not advised, but if you accidentally do and remember far enough out from your next dose, go ahead and take the missing dose. Avoid double dosing Leflunomide, skipping the missing dose if you're just about scheduled for the next one.


Hypersensitive reactions you've had in the past to this medication or others should be communicated to your physician or nurse prior to taking a dose of Leflunomide. Also let the medical staff know if you've had reactions to animals, foods, dyes, perfumes or preservatives in the past. Read and understand the patient information leaflet provided to you with your prescription of Leflunomide, asking any questions of your doctor or pharmacist before you take the medication.

Pediatric patients have not been studied to determine if Leflunomide is safe for them to take or if it affects their conditions. Use of this medication in pediatric patients is up to the attending physician in each patient's case.

Geriatric patients will be able to safely take Leflunomide for their rheumatoid arthritis symptoms, with caution in patients who have nerve-related conditions. Patients with nerve conditions need to have their dosage altered for safety.

Leflunomide is known to be harmful to unborn babies and should not be taken if you are pregnant or if you may become pregnant. You may be required to have a pregnancy test prior to your Leflunomide prescribed treatment to be absolutely certain the drug will not cause fetal harm. While you are taking this medication, it is imperative that women prevent pregnancy with reliable forms of birth control. Women who want to become pregnant, you will be required to stop taking the drug and have blood tests to determine when the Leflunomide is no longer found in your system. Men who are heterosexual and may get their female partners pregnant should discuss this with their physician prior to doing so while they are in treatment with Leflunomide.

Leflunomide can be transmitted through breast milk, so women who are breastfeeding are urged to stop while they are in treatment with this drug or to put off their Leflunomide treatment until they have weaned their children. This drug will cause harmful effects on child development if passed to infants through breast milk.

Rheumatoid arthritis patients are often prescribed multiple medications to help treat their symptoms, Leflunomide being one of them. Some medications work together with no problems and others do not; this is best determined by your doctor. Disclose all medications you are taking prior to your Leflunomide treatment and include any vaccinations you've had recently, any vitamins or herbal therapies you take as well as any over-the-counter remedies that you regularly use.

You may not be a candidate for Leflunomide treatment if you are currently taking:

  • Teriflunomide

Alert your physician if you are taking this drug so that an alternate form of treatment can be safely prescribed for your condition.

The following vaccinations and medications should be avoided during treatment with Leflunomide, if possible:

  • Adenovirus live vaccination type 4
  • Bacillus of Calmette live vaccination
  • Guerin live vaccination
  • Adenovirus live vaccination type 7
  • Measles live vaccination
  • Influenza virus live vaccination
  • Mumps live vaccination
  • Methotrexate
  • Repaglinide
  • Poliovirus live vaccination
  • Rotavirus live vaccination
  • Rosuvastatin
  • Smallpox vaccination
  • Rubella live vaccination
  • Varicella vaccination
  • Typhoid vaccination
  • Yellow Fever vaccination
  • Warfarin

Have a consultation with your physician about any special diet you should follow or foods to avoid while you are taking Leflunomide. Discuss your use of tobacco products or consumption of alcoholic beverages, if applicable, during this time as well. Some of these substances interact poorly with Leflunomide and should be avoided. The patient information leaflet will also outline anything you should avoid.

Patients with the following diseases may experience a decline in their health during treatment with Leflunomide, as this medication has been known to make the disease itself or its symptoms worsen over time. Disclose your full medical history to your doctor prior to starting treatment with Leflunomide, especially if you have:

  • Bone marrow or blood diseases
  • Immune system diseases
  • Infections of any kind and severity
  • Tuberculosis
  • Weakened immune system
  • Diabetes
  • Nerve damage or conditions
  • Kidney or liver disease
  • Lung problems


Your physician will instruct you to schedule regular follow-up appointments to make sure you are tolerating the drug well with no ill health effects and that it is working on your rheumatoid arthritis condition. These visits will most likely include blood tests that will assist the physician in making sure your health is unaffected by the known unwanted symptoms that can occur.

You will also be instructed to monitor your blood pressure with regular readings on a reliable system. Alert your doctor immediately if your blood pressure increases or decreases dramatically for no reason.

Leflunomide is known to be harmful to fetal development and should be avoided in women who are pregnant or may become pregnant and in men who may get their female partners pregnant. Women who may become pregnant will be required to have a pregnancy test prior to taking Leflunomide prescribed treatment to be absolutely certain the drug will not cause fetal harm.

While you are taking this medication, it is imperative that women prevent pregnancy with reliable forms of birth control. Women that wish to become pregnant will be required to stop taking the drug and undergo blood tests until it has been determined that Leflunomide is no longer found in their body. Men with the possibility of getting their female partners pregnant are urged to use reliable forms of barrier-type birth control such as condoms and to be tested if they discontinue the drug to father a child.

Avoid the use of Teriflunomide when you are using Leflunomide and alert your doctor if you have taken either in the past. You may be required to have a blood test to make sure the drug is no longer in your system.

Symptoms such as a light-colored stool, painful upper stomach area, vomiting, nausea and yellow skin or eyes could be symptoms of a serious liver problem caused by taking Leflunomide. Notify your physician at once if you experience any of these symptoms.

Leflunomide has been known to cause a decrease in the number of white blood cells in a patient's body, which increases the risk of infection. The number of blood platelets is also decreased with use of Leflunomide, which makes it harder for wounds to scab over and stop bleeding. Reduce your risk of contracting a serious infection or experience severe bleeding by taking the following cautionary steps:

  • Avoid other people who have colds, flu or other infections.
  • Notify your physician if you begin to experience cold-like symptoms such as coughing, elevated body temperature, chills, hoarse voice, painful side or lower back or difficult urination.
  • Your doctor should be notified if you have stools that are black or tar-like, blood in your urine, bruises or bleeding in unexpected places or tiny red dots on your skin.
  • Use caution when brushing or flossing your teeth and consult your dentist for gentle ways to practice oral hygiene.
  • Avoid touching your face, in particular, your nose and eyes, unless your hands are freshly washed.
  • Use caution when shaving or trimming nails.
  • Avoid dangerous sports with contact situations and other events where bruising is possible.

Leflunomide has been linked with incidences of a serious skin reaction known as DRESS, which includes symptoms of loose, peeling or blistered skin, itching, chills, muscle or joint pain, red lesions on skin with purple middles, skin ulcers or sores, white spots on the lips or in the mouth or weak muscles and fatigue. Alert your physician right away if you have any of these symptoms.

You will need to have a tuberculosis skin test prior to beginning your treatment with Leflunomide. If you or anyone you live with has had a positive test for tuberculosis, let your doctor know this information for your own safety.

Patients taking Leflunomide should be aware that they are at a higher risk for getting some forms of cancer as well as serious infections when they take this drug. This information will be outlined in your patient information leaflet but should be discussed with your doctor if you have any questions or concerns.

Leflunomide patients are at a high risk for a condition known as peripheral neuropathy because they take this drug. Your doctor should be notified if you have symptoms such as numb, burning or tingling hands, feet, arms or legs while you are taking this medication.

Coughing, shortness of breath, elevated body temperature or difficulty breathing while you are taking Leflunomide should be reported to your doctor or nurse immediately.

After you discontinue taking Leflunomide, no matter the reason, you will still have it in your body for a certain period of time. During this time, in addition to avoiding getting pregnant or fathering a child, you should also avoid being vaccinated with a live virus or any other vaccination. You have the risk of contracting the disease you are being vaccinated for due to your low immune activity while taking this drug.

Avoid other medications when you are taking Leflunomide unless specifically approved by your physician. This includes any homeopathic remedies, vitamins, mineral supplements, herbal remedies and over-the-counter medications.


Your Leflunomide tablets should be kept in the original packaging and stored at room temperature. Do not store this medication in an area that is exposed to heat, light or moisture, such as a bathroom counter. Keep this and other medications out of sight and reach of children for safety reasons. Should you need to dispose of any expired or unused Leflunomide, consult your doctor or pharmacist for the safest way to do so depending on the rules in your local area.


Leflunomide is a drug prescribed by doctors for the treatment of rheumatoid arthritis, one of the most common types of arthritis in the world. Patients with this incurable autoimmune disorder experience inflammation in their joints, commonly their hands and wrists. While pain relievers can offer a reduction in symptoms, they do not treat the condition itself. Leflunomide is an inhibitor of one of the enzymes responsible for attacking the joints. By stopping the activity of this enzyme, Leflunomide eases symptoms in a different way from pain relievers, stopping the immune response itself and not just treating the pain. By doing so, Leflunomide is actually credited with slowing the disease's progressive deterioration of the joints that occurs when left untreated.

Adult patients are eligible for Leflunomide treatment, which consists of swallowing one tablet per day in dosage sizes determined for them by their physician. Patients who have compromised liver and bone marrow functions due to existing conditions are typically dosed much lower than patients who do not have these issues. This medication should not be used in women who are pregnant, those who are breastfeeding or in men who may father a child, due to the adverse health effects it has on fetal and child development. Leflunomide should also be avoided if patients are already taking Teriflunomide or if they have recently had a live vaccination of any kind.

As the immune system is directly affected by Leflunomide, white blood cell levels and platelet levels will also be affected. Patients are urged caution when performing oral hygiene or using sharp objects of any kind. They are also warned not to participate in contact sports to avoid unnecessary risk of bruising. Patients should avoid people with colds, flu or other infections as well.

Report any skin conditions that occur while taking Leflunomide as well as any changes in blood pressure or stomach tenderness. These could be the symptoms of an underlying health issue related to unwanted effects of this drug. For your own good health and safety, report any changes in your mood and any symptoms you have to your physician as soon as they occur.