Leflunomid Puren (Leflunomide)

• Leflunomide is used to treat inflammatory joint diseases by modulating immune activity.
• Rheumatoid arthritis: reduces joint inflammation, pain, and structural damage in adult patients.
• Psoriatic arthritis: alleviates skin and joint symptoms, improving functional ability.
• Active rheumatoid arthritis: helps achieve disease remission when combined with other DMARDs.

• Leflunomide is metabolized to its active form, teriflunomide, which inhibits the mitochondrial enzyme dihydroorotate dehydrogenase. This blockade reduces de novo pyrimidine synthesis, limiting proliferation of activated lymphocytes. By suppressing T‑cell expansion and cytokine production, the drug dampens the autoimmune response that drives joint inflammation and damage in rheumatoid and psoriatic arthritis. The effect is selective for rapidly dividing immune cells, sparing most resting cells, which contributes to its therapeutic profile.

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

Common Side Effects

• Headache: mild to moderate intensity.
• Nausea: occasional gastrointestinal upset.
• Diarrhea: loose stools, usually transient.
• Elevated liver enzymes: mild increase in hepatic transaminases.
• Hypertension: increased blood pressure.
• Peripheral neuropathy: tingling sensations.

Serious or Rare Side Effects

• Severe liver injury: hepatitis or hepatic failure requiring monitoring.
• Aplastic anemia: bone marrow suppression leading to pancytopenia.
• Severe cutaneous reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Pulmonary toxicity: interstitial lung disease.
• Stevens‑Johnson syndrome: life‑threatening skin reaction.
• Toxic epidermal necrolysis: extensive skin detachment.

When prescribing Leflunomide, several precautions and monitoring measures are essential to ensure patient safety.

• Baseline liver function: obtain hepatic enzyme tests before initiation.
• Regular liver monitoring: repeat tests monthly for the first three months, then periodically.
• Pregnancy avoidance: contraindicated in pregnancy; ensure effective contraception for both sexes.
• Infection risk: monitor for signs of infection and avoid live vaccines.
• Store at ambient temperature: keep below 25°C, retain in original packaging, protect from moisture.

Leflunomide interacts with several medicines, requiring careful management to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• Warfarin: increased anticoagulant effect, may lead to bleeding.
• Rituximab: reduced efficacy of Leflunomide, may require dose adjustment.

Moderate Interactions (Monitor Closely)

• Methotrexate: additive hepatotoxicity, monitor liver enzymes closely.
• Statins: increased risk of myopathy, observe muscle symptoms.
• Live vaccines: may cause uncontrolled infection, avoid administration.