Marevan (Warfarin Sodium)

Marevan (warfarin) is used in the management of venous and arterial thromboembolic disorders.

• Deep vein thrombosis (DVT): reduces risk of clot extension and recurrence.
• Pulmonary embolism (PE): prevents new clot formation and improves survival.
• Atrial fibrillation (stroke prevention): lowers incidence of embolic stroke.
• Prosthetic heart valve (thromboembolism prophylaxis): maintains valve patency by inhibiting clot formation.

• Warfarin inhibits the enzyme vitamin K epoxide reductase, which is essential for recycling vitamin K to its active form. This blockade reduces the gamma‑carboxylation of vitamin K‑dependent clotting factors II, VII, IX, and X, leading to decreased synthesis of functional clotting proteins and thereby attenuating the coagulation cascade.

Warfarin therapy may be associated with a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Nausea or upset stomach.
• Minor bruising or bleeding from gums.
• Hair loss or thinning.
• Skin rash or itching.

Serious or Rare Side Effects

• Severe bleeding (intracranial, gastrointestinal, or retroperitoneal).
• Warfarin‑induced skin necrosis.
• Anaphylactic or severe allergic reactions.
• Elevated liver enzymes indicating hepatic injury.

When prescribing Marevan, clinicians should consider several safety measures to minimize risk.

• Dose individualization: adjust based on regular INR monitoring and clinical response.
• Renal impairment: monitor more frequently and consider dose reduction.
• Hepatic disease: use with caution due to altered metabolism.
• Concomitant antibiotics: assess interaction risk and adjust monitoring.
• Store at ambient temperature: keep in the original container, protect from moisture and light.

Warfarin interacts with many medicines; awareness of interaction strength guides management.

Major Interactions (Avoid)

• Amiodarone: markedly increases warfarin effect and bleeding risk.
• Azole antifungals (e.g., fluconazole): potentiate anticoagulation.
• Vitamin K supplements: reduce warfarin efficacy.
• Heparin or other anticoagulants: additive bleeding risk.

Moderate Interactions (Monitor Closely)

• NSAIDs (e.g., ibuprofen): increase bleeding tendency.
• Antibiotics such as trimethoprim‑sulfamethoxazole: may raise INR.
• Statins (e.g., simvastatin): modest effect on warfarin metabolism requiring INR checks.