The Ability of a Retrospective Review of Electronic Health Records to Fully Capture the Frequency of Supratherapeutic Dosing of Acetaminophen

I read with great interest the article by Zhou et al¹ and would like to make the following comments. First, I suggest that their findings underestimate the frequency of acetaminophen overexposure because the authors did not take into account the weight of the patients. Indeed, according to guidelines, when body weight is 50 kg or lower, the adult patient should be prescribed 15 mg/kg for a single dose, up to a maximum of 60 mg/kg of body weight for the total daily dose.² My colleagues and I recently performed a prospective study aimed at reporting on the nature and frequency of overdosed acetaminophen prescriptions in adults in a teaching hospital.³ From October 2006 to April 2011, we reviewed 44 404 prescriptions. Pharmacists made 480 alerts related to overdosed acetaminophen prescription. Most pharmacists' alerts (n = 420) were made because of the prescription of single-ingredient acetaminophen only. Among these alerts, body weight was recorded for 353 patients, of whom 312 had a body weight in the range 27 to 50 kg. Our findings highlight that overdosing of acetaminophen for adult patients with low body weight is still frequent. This is a matter of concern because adults with low body weight are at greater risk of liver damage.