Celebrex Half-Life
The elimination half-life of Celebrex (celecoxib) is approximately 11 hours under fasting conditions in healthy adults. 1
Pharmacokinetic Details
According to the FDA drug label, celecoxib demonstrates the following key pharmacokinetic parameters in healthy subjects after a single 200 mg dose 1:
- Effective half-life (t½): 11.2 hours (±31% CV)
- Time to peak concentration (Tmax): 2.8 hours (approximately 3 hours)
- Peak plasma concentration (Cmax): 705 ng/mL
- Apparent clearance (CL/F): 27.7 L/hr (approximately 500 mL/min)
- Apparent volume of distribution (Vss/F): 429 L (approximately 400 L at steady state)
The drug reaches steady-state conditions on or before Day 5 with multiple dosing 1.
Important Clinical Variations
Population-Specific Differences
Elderly patients experience significantly altered pharmacokinetics:
- 40% higher Cmax
- 50% higher AUC compared to younger subjects
- Elderly females show even higher levels due to lower body weight 1
Hepatic impairment substantially affects celecoxib elimination:
- Mild impairment (Child-Pugh Class A): ~40% increase in AUC
- Moderate impairment (Child-Pugh Class B): ~180% increase in AUC
- Dose reduction of approximately 50% is required for moderate hepatic impairment 1
Pediatric patients show markedly different pharmacokinetics:
- Elimination half-life is approximately 3.7 hours (roughly half that of adults)
- Drug clearance is approximately twice as fast as in adults 2
- This necessitates different dosing strategies in children
Food Effects
When taken with a high-fat meal, celecoxib absorption is delayed by 1-2 hours with a 10-20% increase in total absorption (AUC). However, doses up to 200 mg twice daily can be administered without regard to meals 1.
Metabolism and Elimination
Celecoxib is eliminated predominantly through hepatic metabolism via CYP2C9 (primary pathway) with minimal unchanged drug (<3%) recovered in urine and feces. Following radiolabeled drug administration 1:
- 57% excreted in feces
- 27% excreted in urine
- Primary metabolite is the carboxylic acid form (73% of dose)
The low aqueous solubility of celecoxib prolongs the absorption process, making terminal half-life determinations more variable 1.
Clinical Implications
The 11-hour half-life supports twice-daily dosing for most indications. However, dose adjustments are mandatory for patients with moderate hepatic impairment and should be considered for elderly patients, particularly those weighing less than 50 kg 1. The drug's extensive protein binding (~97%, primarily to albumin) and hepatic metabolism via CYP2C9 create potential for drug interactions with other CYP2C9 substrates or inhibitors 3.