Leflunomide Zentiva (Leflunomide)

Leflunomide is a disease‑modifying antirheumatic drug that targets inflammatory joint disorders.

• Rheumatoid arthritis: reduces joint inflammation, pain and structural damage.
• Psoriatic arthritis: improves skin lesions and joint symptoms.
• Adults with active disease when other DMARDs are insufficient: provides an alternative disease‑modifying option.

• Leflunomide inhibits the mitochondrial enzyme dihydroorotate dehydrogenase, which blocks de novo pyrimidine synthesis. This limits the proliferation of activated lymphocytes, thereby reducing the immune‑mediated inflammation that drives rheumatoid and psoriatic arthritis.

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

Common Side Effects

• Diarrhoea: loose stools occurring during early treatment.
• Nausea: occasional upset stomach or feeling of queasiness.
• Alopecia: reversible hair thinning or loss.
• Rash: mild skin eruptions or itching.
• Elevated liver enzymes: mild increases in ALT/AST.
• Hypertension: modest rise in blood pressure.

Serious or Rare Side Effects

• Severe liver injury: jaundice, fatigue, dark urine.
• Stevens‑Johnson syndrome: severe skin blistering and mucosal involvement.
• Bone‑marrow suppression: low blood counts, increased infection risk.
• Interstitial lung disease: persistent cough, shortness of breath.
• Severe infections: opportunistic bacterial or viral illnesses.
• Teratogenicity: potential birth defects if exposure occurs during pregnancy.

Before initiating Leflunomide, clinicians should assess baseline health and monitor ongoing safety.

• Liver function monitoring: check ALT/AST before start and periodically thereafter.
• Blood pressure control: measure regularly, especially in hypertensive patients.
• Pregnancy avoidance: do not use in women who are pregnant or may become pregnant.
• Infection vigilance: postpone therapy in active severe infections.
• Renal impairment caution: adjust use in patients with significant kidney dysfunction.
• Store below 25°C: keep in the original pack, protect from moisture.

Leflunomide interacts with several medicines, requiring careful management.

Major Interactions (Avoid)

• Warfarin: increased anticoagulant effect, risk of bleeding.
• Statins: heightened risk of liver toxicity.
• Live vaccines: possible severe infection due to immunosuppression.
• Carbamazepine: reduces Leflunomide plasma levels, lowering efficacy.
• Azathioprine: additive bone‑marrow suppression.

Moderate Interactions (Monitor Closely)

• NSAIDs: may raise liver enzyme levels.
• Methotrexate: combined hepatotoxic potential.
• Antihypertensives: possible reduction in blood‑pressure control.
• Oral contraceptives: decreased hormonal efficacy.
• Allopurinol: increased risk of rash and hypersensitivity.