Re-examination of effect of paracetamol on serum uric acid measured by phosphotungstic acid reduction.

The drug paracetamol (N-acetyl-p-aminophenol; acetaminophen) caused a spurious increase in serum uric acid measured by phosphotungstic acid reduction methods. However, the increase was less than 0.12 mmol/1 at plasma levels of paracetamol found in overdosage (40 mg/100 ml) and was small at therapeutic concentrations (less than 4 mg/100 ml). It is concluded that few patients with joint pain who have taken paracetamol paracetamol as an analgesic will have clinically misleading values for serum uric acid.