Leflunomida Cinfa (Leflunomide)

• Leflunomide is employed in autoimmune inflammatory joint diseases to modify disease activity and prevent structural damage.
• Rheumatoid arthritis: reduces joint inflammation, pain, and slows radiographic progression.
• Psoriatic arthritis: improves skin lesions and joint symptoms, decreasing functional impairment.
• Active disease not adequately controlled by other DMARDs: offers an alternative mechanism of action for patients requiring additional therapeutic options.

• Leflunomide inhibits the mitochondrial enzyme dihydroorotate dehydrogenase, which is essential for de novo pyrimidine synthesis. By limiting pyrimidine availability, it suppresses proliferation of activated lymphocytes, thereby reducing the autoimmune response that drives inflammation in rheumatoid and psoriatic arthritis.

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

Common Side Effects

• Diarrhea: loose stools that may be intermittent.
• Nausea: feeling of stomach upset, sometimes with vomiting.
• Alopecia: thinning or loss of scalp hair.
• Rash: mild skin eruptions or itching.
• Elevated liver enzymes: increase in ALT/AST detected on labs.
• Hypertension: rise in blood pressure requiring monitoring.

Serious or Rare Side Effects

• Severe liver injury: jaundice, hepatitis, or hepatic failure.
• Bone marrow suppression: anemia, leukopenia, or thrombocytopenia.
• Pulmonary toxicity: interstitial lung disease or pneumonitis.
• Stevens‑Johnson syndrome/toxic epidermal necrolysis: severe skin reactions.
• Serious infections: opportunistic infections due to immunosuppression.
• Teratogenicity: fetal malformations when exposure occurs during pregnancy.

• Before initiating therapy, clinicians should evaluate patient history and conduct baseline laboratory tests.
• Pregnancy contraindication: avoid use in pregnancy (Category X) and discontinue well before conception.
• Liver function monitoring: obtain baseline ALT/AST and repeat periodically during treatment.
• Hematologic monitoring: perform complete blood counts at baseline and during therapy.
• Infection screening: assess for latent tuberculosis and avoid live vaccines while on therapy.
• Store below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Leflunomide can alter the pharmacokinetics or pharmacodynamics of several co‑administered drugs.

Major Interactions (Avoid)

• Warfarin: increased anticoagulant effect, risk of bleeding.
• Live vaccines: heightened risk of vaccine‑derived infection.
• Cholestyramine: reduces leflunomide absorption and exposure.

Moderate Interactions (Monitor Closely)

• Statins: potential for increased muscle toxicity.
• Oral contraceptives: reduced hormonal efficacy, consider alternative contraception.