Introduction
Leflunomide is an immunomodulatory and anti-inflammatory medication primarily used in the treatment of autoimmune diseases like rheumatoid arthritis. It belongs to the class of disease-modifying antirheumatic drugs (DMARDs) and helps to slow disease progression and reduce inflammation. Leflunomide is often used when patients do not respond adequately to other DMARDs like methotrexate.
Uses
Leflunomide is used for:
- Treatment of rheumatoid arthritis to reduce symptoms like pain, swelling, and stiffness
- Treatment of psoriatic arthritis
- Sometimes used off-label for other autoimmune conditions like lupus or vasculitis
| Brand Name | Leflunomide |
|---|---|
| Type | |
| Weight | |
| Generic | Leflunomide |
| Manufacturer | |
| Available in | English বাংলা |
Mechanism of Action
Leflunomide works by inhibiting pyrimidine synthesis, which is crucial for the proliferation of activated T and B lymphocytes, the cells responsible for inflammation and damage in autoimmune diseases. By reducing the production of these cells, leflunomide helps modulate the immune response and reduces inflammation.
How Long Does It Take to Work?
Leflunomide may take several weeks to start working, with significant improvements usually seen after 4 to 6 weeks. In some cases, the full therapeutic effect may not be evident for up to 12 weeks.
Absorption
Leflunomide is well absorbed after oral administration, with a bioavailability close to 80-90%. It is converted into its active metabolite, teriflunomide, which is responsible for its therapeutic effects.
Route of Elimination
Leflunomide is eliminated primarily through the biliary-fecal route, with some renal excretion. Its active metabolite, teriflunomide, is slowly eliminated, and it can persist in the body for an extended period, requiring the use of a cholestyramine washout procedure to expedite clearance in certain cases (e.g., pregnancy).
Dosage
Leflunomide once-daily oral dosing for rheumatoid arthritis patients. After a loading dose of 100 mg once daily for 3 days, the maintenance dose is 20 mg once daily. Leflunomide does not require step wise dose increment over time. The dose may be decreased to 10 mg daily if tolerability issues arise.The typical dose for rheumatoid arthritis is an initial loading dose of 100 mg per day for 3 days, followed by a maintenance dose of 20 mg once daily. In some cases, the maintenance dose may be reduced to 10 mg daily depending on the patient’s response and tolerance to the medication.
Administration
Leflunomide is administered orally in tablet form. It can be taken with or without food. It is important to follow the prescribed dosage regimen carefully, and patients should not discontinue the drug abruptly without consulting their healthcare provider.
Side Effects
Common side effects of leflunomide include:
- Diarrhea
- Nausea
- Hair thinning or loss
- Elevated liver enzymes
- Hypertension
- Rash
- Liver toxicity (hepatotoxicity)
- Severe infections due to immunosuppression
- Peripheral neuropathy
Toxicity
Leflunomide can cause hepatotoxicity, especially in patients with preexisting liver conditions or when used in combination with other hepatotoxic drugs. Regular monitoring of liver enzymes is recommended during treatment. In cases of overdose, cholestyramine or activated charcoal can be used to accelerate elimination of the drug.
Precautions
Patients taking leflunomide should undergo regular monitoring of liver function and blood counts. It should be used cautiously in patients with a history of liver disease, and alcohol consumption should be limited to avoid further risk of liver damage. Leflunomide can suppress the immune system, increasing the risk of infections.
Interaction
Leflunomide has several potential drug interactions:
- It should not be used with other hepatotoxic drugs (e.g., methotrexate) without careful monitoring.
- Drugs that inhibit or induce cytochrome P450 enzymes (e.g., rifampin) may affect leflunomide levels.
- Concurrent use of warfarin may require closer monitoring of INR levels due to an increased risk of bleeding.
Disease Interaction
Leflunomide should be used cautiously in patients with:
- Preexisting liver disease or elevated liver enzymes
- Active infections
- Immunosuppressed states
Drug Interaction
Significant drug interactions include:
- Warfarin: Increased risk of bleeding; monitor INR closely.
- Methotrexate: Increased risk of hepatotoxicity; monitor liver function.
- CYP2C8 inhibitors (e.g., gemfibrozil) and inducers (e.g., rifampin) can alter leflunomide concentrations.
Food Interactions
Leflunomide can be taken with or without food, and there are no significant food interactions. However, alcohol should be avoided due to the increased risk of liver toxicity.
Pregnancy Use
Leflunomide is contraindicated in pregnancy due to its teratogenic effects. Women of childbearing potential should use effective contraception while taking leflunomide, and if pregnancy is planned, a cholestyramine washout procedure is recommended to remove the drug from the system.
Lactation Use
It is not known whether leflunomide is excreted in human breast milk. However, due to the potential for serious adverse effects in nursing infants, breastfeeding is not recommended while taking leflunomide.
Acute Overdose
In cases of leflunomide overdose, cholestyramine or activated charcoal can be administered to accelerate the drug’s elimination. Symptoms of overdose may include liver toxicity, gastrointestinal distress, and immunosuppression. Prompt medical intervention is necessary.
Contraindication
Leflunomide is contraindicated in:
- Patients with known hypersensitivity to leflunomide or its components
- Pregnant women or women planning pregnancy
- Severe liver impairment
- Severe immunodeficiency
Use Direction
Leflunomide is taken orally, usually once daily. It is important to follow the prescribed regimen without skipping doses. In the event of missed doses, patients should consult their healthcare provider.
Storage Conditions
Store leflunomide at room temperature (20°C to 25°C), protected from moisture and light. Keep out of reach of children and do not use past the expiration date.
Volume of Distribution
Leflunomide has a large volume of distribution (approximately 0.13 L/kg), indicating that it distributes extensively into body tissues.
Half Life
The half-life of leflunomide's active metabolite, teriflunomide, is long, ranging from 15 to 18 days, which contributes to its prolonged effects even after discontinuation.
Clearance
Clearance of leflunomide primarily occurs via hepatic metabolism and biliary excretion. Teriflunomide is eliminated slowly, which can be accelerated with cholestyramine in cases of toxicity or when rapid drug elimination is necessary (e.g., pregnancy).
See in details version Leflunomide also Leflunomide in bangla
