Leflunomid "egis" (Leflunomide)

Leflunomide is a disease‑modifying antirheumatic drug that modulates immune activity in several inflammatory arthritis conditions, offering a systemic approach to disease control.

• Rheumatoid arthritis: reduces disease activity scores, slows radiographic joint damage, and improves functional outcomes and quality of life.
• Psoriatic arthritis: alleviates joint inflammation, diminishes skin plaque severity, and contributes to better overall disease control.
• Juvenile idiopathic arthritis: controls systemic inflammation, reduces joint swelling, and enhances mobility and daily activity participation in children.

• Leflunomide is metabolized to its active form, teriflunomide, which selectively inhibits the mitochondrial enzyme dihydroorotate dehydrogenase. By blocking this key step in de novo pyrimidine synthesis, the drug reduces the proliferation of activated T‑lymphocytes and B‑lymphocytes, thereby dampening the autoimmune response that drives joint inflammation in rheumatoid and related arthritides. The inhibition is reversible and leads to a decrease in cytokine production and inflammatory cell infiltration in synovial tissue.

Leflunomide may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Diarrhea: mild to moderate watery stools.
• Nausea: occasional feeling of stomach upset.
• Elevated liver enzymes: transient increase in ALT/AST.
• Hair loss: temporary thinning of scalp hair.

Serious or Rare Side Effects

• Severe liver injury: hepatitis or hepatic failure.
• Hematologic abnormalities: neutropenia, anemia, or thrombocytopenia.
• Pulmonary toxicity: interstitial lung disease or severe pneumonia.

Before initiating leflunomide, several precautions should be observed to minimize risk.

• Liver function monitoring: obtain baseline tests and repeat regularly during therapy.
• Hematologic assessment: check complete blood count before start and periodically thereafter.
• Pregnancy avoidance: contraindicated in pregnancy; ensure effective contraception for women of childbearing potential.
• Infection vigilance: screen for active infections and advise patients to report signs promptly.
• Teratogenic risk counseling: discuss the X pregnancy category and the need for reliable birth control.
• Store at room temperature: keep in original packaging, protect from moisture and heat.

Leflunomide can interact with several medicines, altering efficacy or safety.

Major Interactions (Avoid)

• Warfarin: increased anticoagulant effect, risk of bleeding.
• Teriflunomide (or other DHODH inhibitors): additive toxicity, avoid co‑administration.
• Live vaccines: heightened risk of infection, contraindicated during therapy.

Moderate Interactions (Monitor Closely)

• Methotrexate: potential for enhanced hepatotoxicity, monitor liver enzymes.
• Statins: possible increase in statin plasma levels, watch for myopathy.
• Antihypertensives (e.g., ACE inhibitors): may require dose adjustment due to altered renal clearance.