Leflunomid 1 A Pharma (Leflunomide)

Leflunomide is a disease-modifying antirheumatic drug (DMARD) used to treat inflammatory arthritis conditions.

• Rheumatoid arthritis: reduces joint inflammation, pain, and slows radiographic progression.
• Psoriatic arthritis: improves skin lesions and joint symptoms while limiting disease progression.
• Active rheumatoid arthritis refractory to methotrexate: provides an alternative therapeutic option when first‑line DMARDs are insufficient.

• Leflunomide is metabolized to its active teriflunomide, which selectively inhibits dihydroorotate dehydrogenase, a key enzyme in the de novo pyrimidine synthesis pathway. By blocking pyrimidine production, the drug limits proliferation of activated T‑lymphocytes and other immune cells, thereby reducing the inflammatory response that drives joint damage in autoimmune arthritis. The inhibition also diminishes B‑cell activity and downstream cytokine release, contributing further to immunosuppression.

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

Common Side Effects

• Diarrhea: loose stools or increased frequency.
• Nausea: feeling of sickness or urge to vomit.
• Elevated liver enzymes: increased ALT/AST levels.
• Hypertension: raised blood pressure.
• Rash: mild skin irritation or redness.
• Headache: persistent or intermittent head pain.

Serious or Rare Side Effects

• Severe liver injury: hepatitis or hepatic failure.
• Bone marrow suppression: anemia, leukopenia, or thrombocytopenia.
• Severe cutaneous reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Interstitial lung disease: breathing difficulties and pulmonary infiltrates.

When prescribing Leflunomide, clinicians should consider several safety precautions to minimize risk.

• Pregnancy: avoid use; teriflunomide is teratogenic and requires thorough contraception.
• Liver function: monitor baseline and periodic hepatic enzymes; discontinue if significant elevation occurs.
• Hematology: assess complete blood count regularly to detect bone‑marrow suppression.
• Infections: screen for latent infections and monitor for signs of opportunistic infection.
• Drug interactions: review concomitant medications that may increase hepatic toxicity or immunosuppression.
• Store at ambient temperature: keep below 25 °C in the original container, protect from moisture and light.

Leflunomide can interact with other medicines, affecting its safety or efficacy.

Major Interactions (Avoid)

• Methotrexate: combined use increases risk of hepatotoxicity and bone‑marrow suppression.
• Strong CYP1A2 inducers (e.g., rifampicin, carbamazepine): markedly reduce teriflunomide plasma levels, decreasing effectiveness.

Moderate Interactions (Monitor Closely)

• Warfarin: may enhance anticoagulant effect; monitor INR closely.
• Antiviral agents (e.g., acyclovir): potential for increased toxicity; observe renal function.
• Live vaccines: immunosuppression may diminish vaccine efficacy and increase infection risk.