Essential Blood Tests While Taking Leflunomide

Leflunomide is a medication commonly used to treat rheumatoid arthritis and other autoimmune conditions. It helps reduce inflammation and slow down joint damage. However, because leflunomide can affect the liver and blood cells, regular monitoring through blood tests is crucial for anyone taking this medication.

Key Blood Tests for Leflunomide

Before starting leflunomide, certain blood tests are recommended to establish a baseline and check for potential issues. These tests include:

• Serum Alanine Aminotransferase (ALT): This enzyme is found in the liver, and its levels are used to assess liver health. A baseline ALT test is necessary, and patients with liver disease or ALT levels more than twice the normal limit should not use leflunomide.
• White Blood Cell Count: This test measures the number of white blood cells, which are crucial for fighting infections. Monitoring helps ensure the immune system remains healthy.
• Haemoglobin or Haematocrit: These tests assess the amount of oxygen-carrying protein in the blood and the proportion of blood volume that is composed of red blood cells, respectively. They help detect anemia or other blood-related issues.
• Platelet Count: Platelets are essential for blood clotting. Monitoring platelet levels helps prevent bleeding complications.
• Tuberculosis Screening: This is important to rule out latent tuberculosis, as leflunomide can increase the risk of activating the infection.
• Pregnancy Test: For women who can become pregnant, this test ensures that they are not pregnant before starting leflunomide, as the medication can harm an unborn baby.

Monitoring During Treatment

Once treatment with leflunomide begins, regular monitoring is essential:

• ALT Levels: ALT should be checked monthly for the first six months and then every 6 to 8 weeks. If ALT levels rise to more than three times the normal limit, treatment is paused, and further investigation is needed.
• Blood Cell Counts: White blood cell, haemoglobin, and platelet counts are monitored monthly for the first six months and then every 6 to 8 weeks. If leflunomide is used with methotrexate, monthly monitoring continues.
• Blood Pressure: This should be checked before starting leflunomide and periodically thereafter.

Special Considerations

• Combination with Methotrexate: If taking both leflunomide and methotrexate, follow the American College of Rheumatology's guidance for liver monitoring, which includes additional tests such as AST (aspartate aminotransferase) and serum albumin.
• Warfarin Use: Leflunomide can affect INR (International Normalized Ratio), a measure of blood clotting. Close INR monitoring is necessary if you are also taking warfarin.

Frequently asked questions

What should I do if my ALT levels are high?
If your ALT levels are more than three times the normal limit, your doctor may pause leflunomide and investigate the cause. An accelerated drug elimination procedure might be used to clear the medication from your system.

Can I take leflunomide with other medications?
Leflunomide can interact with other medications, especially those affecting the liver or immune system. Always discuss any other medications with your doctor.

Why is pregnancy testing required before starting leflunomide?
Leflunomide can cause harm to an unborn baby, so it is essential to confirm that you are not pregnant before starting the medication.

How often should blood pressure be monitored?
Blood pressure should be checked before starting leflunomide and periodically during treatment, as the medication can affect blood pressure.

What is an accelerated drug elimination procedure?
This procedure helps remove leflunomide from your system faster if there are concerns about liver damage or other serious side effects.

When to see a doctor

You should consult your doctor if you notice symptoms such as unusual fatigue, yellowing of the skin or eyes, dark urine, or any signs of infection like fever or sore throat. These could indicate liver problems or blood-related issues.

Remember, this information is for educational purposes and any decisions regarding your treatment should be made in consultation with your healthcare provider.