Arava belongs to a class of medications known as pyrimidine synthesis inhibitors.
Arava is available as oral tablets in 10 mg, 20 mg, and 100 mg doses.
A dose of 10 mg or 20 mg is usually taken once a day as a single tablet. In some cases, it may be prescribed every other day.
Rheumatologists used to start Arava with three loading doses of 100 mg per day. This is not usually done any more because there is a greater risk of side effects at this dose.
Arava Takes 6 to 8 Weeks to Start Working
It usually takes 6 to 8 weeks for Arava to start working, and it can take up to 6 months to feel the maximum effect.
It is important for patients starting this medicine to keep taking it as prescribed. If the dose is changed, it can take another 6 to 8 weeks to start feeling the effects of the change.
How to Take Arava After Missing a Dose
If a patient forgets to take Arava at their usual time but remembers later on the same day, the missed dose should be taken immediately.
If yesterday’s dose is forgotten, it should be skipped, and the patient should only take their usual dose for the day.
Important Tests and Risks
Regular Blood Tests
Patients taking Arava should have their blood tested every month. It is important to make sure that this medicine isn’t harming the liver or blood counts.
Risk of Combination with Alcohol
Drinking while taking Arava can harm the liver. Patients taking this medicine are advised to stop drinking and avoid alcohol, or at the very least, significantly reduce their consumption of alcohol.
Risk of Infection
Arava can make it a bit harder for people to fight off infections. People taking this medicine should call their doctor they have a fever, think they have an infection, or have been prescribed antibiotics to treat an infection.
Patients taking Arava should coordinate with their doctor to potentially stop treatment around surgery. It can be re-started once things have healed and there’s no sign of infection.
Risk in Pregnancy
Arava can harm an unborn child. Patients who may become sexually active during treatment with this medication are advised to use reliable birth control.
How Arava Works
Arava works by suppressing the immune system. It does this by inhibiting an enzyme called dihydroorotate dehydrogenase.
The dihydroorotate dehydrogenase enzyme is associated with a number of functions in the body including the synthesis, or creation, of pyrimidines. This effect makes Arava a member of a class of medications called pyrimidine synthesis inhibitors.
Some of the most important building blocks of DNA and RNA that encode genetic information are derived from pyrimidines: cytosine (C) which is found in both DNA and RNA, thymine (T) which is found in DNA, and uracil (U) which is found in RNA.
The exact mechanisms of how Arava suppresses the immune system is not fully understood.
Many researchers think that Arava suppresses the immune system by depleting the pyrimidine supply used by T-cells, a type of white blood cell in the immune system. It is thought that T-cells need a good supply of pyrimidines to divide and rapidly create more copies of themselves.
Researchers also suspect that other more complex cellular signalling pathways might be involved too.
More research will help to better understand how the immune system becomes suppressed in those who take Arava.
In many types of arthritis, the immune system is not functioning correctly and attacks the body by mistake. By suppressing the immune system, Arava helps stop this attack.
In people with arthritis, this medicine can help reduce pain and swelling (inflammation) in the joints, improve day to day function, and prevent long-term damage caused by joint inflammation.
The suppression of the immune system can also make it a bit harder for the body to fight infections, so people taking Arava should report any fevers or infections to their doctor.
The most common side effect of Arava is nausea and diarrhea.
Monthly blood tests are important to ensure that Arava does not harm the liver or blood counts.
Patients should stop drinking alcohol while taking Arava to reduce the chances of liver side effects.
Arava may cause birth defects and result in miscarriage. Anyone who becomes pregnant while taking this medicine should notify a doctor immediately.
Patients considering pregnancy should consider using a different medication because Arava can stay in the body for up to two years.
MORE COMMON side-effects include:
- Nausea and diarrhea
- Skin rash
- Hair thinning or loss which is reversible when the medication is stopped
RARE side-effects include:
- Blood Pressure – Arava can rarely cause an increase in blood pressure. Patients starting Arava should tell their doctor if they have high blood pressure.
- Liver – Arava may irritate the liver. This does not usually cause symptoms but may be found on blood tests. Liver side effects are rare and are usually reversible when caught early through regular monthly blood tests.
- Bone Marrow – Arava can cause a drop in the numbers of white blood cells (which help fight infection) and platelets (which help to stop bleeding). With monthly blood tests, it is unusual for this to be a serious problem.
- Infection – Any infections or fevers should be taken seriously and reviewed by a doctor.
- Tingling in the Hands and Feet – Arava can rarely cause a “pins and needles” feeling, or tingling in the hands and feet.
- Trouble Breathing – Arava can very rarely cause an allergic reaction in the lungs. Patients should call a doctor if they develop a cough that won’t go away, or develop shortness of breath.
How to minimize the side-effects of Arava:
- Patients should get regular blood tests as requested by their doctor (usually monthly) to monitor for side effects, and remember to attend their appointments
- In cases where side effects are a problem, reducing the dose or taking the medicine every other day can often help reduce them. This should only be done with guidance from a doctor.
Who Should NOT Take Arava
Patients who should NOT be taking Arava (Leflunomide) include:
- Patients who have had a previous serious reaction to Arava.
- Women who are pregnant, planning on becoming pregnant, or currently breast feeding.
- Men who are planning pregnancy with their partner.
- Patients with diseases of the liver, kidney, or blood disorders.
- Patients with active infections.
Patients who are about to have surgery should discuss stopping Arava with their doctor. Patients who become pregnant while taking Arava should notify their doctor immediately.
When to Call a Doctor
Patients should call their doctor if they feel sick and want to stop, or they are concerned about any side effects.
Other reasons to call a doctor while taking Arava include:
- Severe weight loss
- Shortness of breath
- Developing a rash
- Becoming pregnant or planning pregnancy
- Before having surgery
Watch rheumatologist Dr. Andy Thompson introduce Arava in a short 3-minute video: