Etodolac + Paracetamol Tablets

Mechanism

Etodolac belongs to a class of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs). These drugs are used for the management of mild to moderate pain, fever, and inflammation. They work by reducing the levels of prostaglandins, which are chemicals that are responsible for pain and the fever and tenderness that occur with inflammation. Etodolac blocks the enzyme that makes prostaglandins (cyclooxygenase), resulting in lower concentrations of prostaglandins. As a consequence, inflammation, pain and fever are reduced. Paracetamol is thought to act primarily in the CNS, increasing the pain threshold by inhibiting cyclooxygenase, COX-1, COX-2, and COX-3 enzymes involved in prostaglandin (PG) synthesis. Paracetamol indirectly blocks COX, and that this blockade is ineffective in the presence of peroxides. Paracetamol is effective in the central nervous system and in endothelial cells but not in platelets and immune cells which have high levels of peroxides. The antipyretic properties of paracetamol are likely due to direct effects on the heat-regulating centres of the hypothalamus resulting in peripheral vasodilation, sweating and hence heat dissipation.

Pharmacokinetics

• Absorption: Etodolac is well absorbed orally (≥80%), with peak plasma levels within 80 ± 30 minutes. Paracetamol is rapidly absorbed from the gastrointestinal tract.
• Distribution: Etodolac is highly protein bound (>99%), while Paracetamol has plasma protein binding less than 20%.
• Metabolism: Etodolac undergoes extensive hepatic metabolism. Paracetamol is metabolized in the liver primarily via glucuronidation and sulfation, with minor CYP-mediated oxidation.
• Elimination: Etodolac is excreted via urine and feces. Paracetamol is eliminated through renal excretion of metabolites.
• Half-life: Etodolac has a half-life of approximately 7 hours, while Paracetamol’s half-life is about 1–3 hours.

Side Effects

• Nausea
• Dyspepsia
• Abdominal pain
• Dizziness
• Edema
• Rare: gastrointestinal bleeding, Stevens-Johnson syndrome

Contraindication

• Hypersensitivity to Etodolac, Paracetamol, or NSAIDs
• Asthma or allergic reactions to aspirin/NSAIDs
• Severe hepatic or renal impairment
• Active GI bleeding or peptic ulcer

Interaction

• Alcohol: Concomitant use with Etodolac increases risk of gastrointestinal bleeding; with Paracetamol increases risk of hepatotoxicity.
• Anticoagulants (e.g., Warfarin): Etodolac may enhance bleeding risk; Paracetamol may increase INR when used chronically.
• Other NSAIDs / Aspirin: Additive gastrointestinal toxicity with Etodolac; minimal interaction with Paracetamol but avoid excessive use.
• Cytochrome P450 interactions: Etodolac metabolism may be affected by CYP3A4 inhibitors/inducers; Paracetamol metabolism influenced by enzyme inducers (carbamazepine, rifampicin, phenytoin) increasing hepatotoxic risk.
• Nephrotoxic drugs: Etodolac combined with cyclosporin or aminoglycosides increases renal risk; Paracetamol generally safe but caution in renal impairment.
• Other agents: Etodolac may interact with phenytoin and zidovudine; Paracetamol interacts with chloramphenicol, cimetidine, isoniazid, and metoclopramide (enhanced absorption).

Warning and Precautions

• Monitor renal and hepatic function during therapy
• Use cautiously in patients with cardiovascular disease
• Discontinue if gastrointestinal bleeding occurs
• Long-term use may increase risk of cardiovascular events
• Use lowest effective dose for shortest duration possible