Bioavailability of aspirin in the presence of dextropropoxyphene/paracetamol combination

Abstract

The effect of 2 doses of a combination analgesic preparation (each dose containing 65 mg dextropropoxyphene hydrochloride and 650 mg paracetamol) upon plasma salicylate concentration after a single dose of soluble aspirin (1.2 g) or enteric-coated aspirin (1.2 g) was examined in 6 normal volunteers and compared with the effect of placebo. The dextropropoxyphene/paracetamol caused no reduction in the plasma salicylate level after absorption of soluble aspirin compared with placebo and, although a reduction in plasma salicylate was seen after enteric-coated aspirin in a single subject, this may reflect erratic absorption rather than a drug interaction.