Duration of Action of Etodolac Extended Release Tablets
Etodolac extended release tablets provide analgesia for approximately 12-24 hours with once-daily dosing, maintaining therapeutic plasma concentrations throughout the dosing interval. 1, 2
Pharmacokinetic Profile of Extended Release Formulation
- The extended release (SR) formulation of etodolac exhibits a longer time to peak concentration compared to conventional-release tablets, with maximum plasma concentrations (Cmax) reached in approximately 3-6 hours rather than 1-2 hours 2
- The elimination half-life of etodolac remains 6-8 hours regardless of formulation (conventional or extended release), which is consistent across both enantiomers 3, 2, 4
- Etodolac SR maintains comparable fluctuation ratios upon multiple dosing when compared to twice-daily conventional-release formulations at equal total daily doses 2
Clinical Duration of Analgesic Effect
- Simulation analyses for etodolac SR demonstrate that pain intensity difference (PID) responses are maintained over the full 24-hour dosing interval 2
- The extended release formulation was specifically designed to provide once-daily dosing while maintaining therapeutic efficacy throughout the day, making it suitable for chronic pain management in conditions like osteoarthritis 2, 5
- Clinical trials in osteoarthritis patients demonstrated that 600 mg of etodolac SR once daily provided sustained efficacy over 8 weeks of treatment 5
Comparison to Conventional Release Formulation
- Conventional-release etodolac (200-400 mg) provides analgesia for 4-6 hours, with 200 mg doses averaging 4-5 hours of relief and 400 mg doses averaging 5-6 hours 1
- The onset of analgesia with conventional-release etodolac occurs approximately 30 minutes after oral administration, with peak analgesic effect between 1-2 hours 1, 6
- The extended release formulation sacrifices rapid onset for prolonged duration, making it more appropriate for chronic conditions rather than acute pain management 2
Important Clinical Considerations
- Food (high-fat meals) does not affect the area under the curve (AUC) for either conventional or extended release etodolac formulations, allowing flexible administration with or without meals 2
- Etodolac exhibits linear pharmacokinetics with good oral bioavailability and greater than 99% protein binding, with clearance being almost exclusively hepatic (non-renal) 2
- No dosage adjustments are necessary in elderly patients, patients with mild-to-moderate renal impairment, or patients with stable hepatic cirrhosis, as pharmacokinetic parameters remain unchanged in these populations 4, 5