Table 3.
Variation in pharmacokinetic properties of paracetamol in the presence or absence of caffeine
| PK of paracetamol 1000 mg/caffeine 130 mg combination (paracetamol/caffeine ratio 7.69:1) | PK of paracetamol alone | ||
|---|---|---|---|
| Paracetamol | Caffeine | ||
| Cmax | 23 µg/ml | 4.3 µg/ml | 20 µg/ml |
| tmax | 30 min | 30 min | 30–60 min |
| AUC0–t | 68 µg/ml | 28 µg/ml | 60 µg/ml |
| t1/2 | 4 h | 5 h | 2 h |
| Distribution volume | 0.9 L/kg | 0.5–0.7 L/kg | 0.9 L/kg |
| Metabolism | Hepatic | Hepatic | Hepatic |
| Excretion |
Urinary 2–5% of unchanged dose |
Urinary 1–5% of unchanged dose |
Urinary < 5% of unchanged dose |