- A phenylacetic acid derivative
- Used to treat mild-moderate pain and/or reduce opioid use
- Particularly beneficial for renal colic
- Side-effects limit its use
Presentation and dose
- Oral, rectal, topical and parenteral (IV/IM) formulations
- Adult dose 150mg/day (in divided doses)
- Paediatric dose of 1mg/kg TDS
Pharmacokinetics
- Oral bioavailability only 50%
- Distribution
- Highly protein bound: 99%
- Small volume of distribution: 0.15 L/kg
- Metabolised via hepatic hydroxylation/conjugation to inactive metabolites
- Elimination half life 1-2hrs
- Excretion in urine (60%) and bile (40%)
Pharmacodynamics
- Cardiovascular: increased risk of coronary events with chronic use (similar to COX-2 inhibitors)
- Gastrointestinal: reduced gastric irritation compared to aspirin and indomethacin
- Renal: may precipitate renal impairment
- Pain on injection:
- IM route painful and may cause muscle damage
- IV route may cause local thrombosis
- Drug interactions: increases the plasma concentration of digoxin and lithium