Public awareness of acetaminophen and risks of drug induced liver injury: Results of a large outpatient clinic survey.

Acetaminophen is one of the most commonly consumed analgesics world wide. Generally perceived as a safe medication, it is the most common cause of acute liver failure in the United States with inadvertent hepatotoxicity in half of all cases. We therefore conducted a survey on the public perceptions of acetaminophen in patients attending the outpatient clinic in Vancouver, Canada. Among 928 patients who were asked, 765 completed the survey questionnaire. The majority of respondents were female (59%), Caucasian (61%), and educated beyond the secondary school level (81%). 23% reported using acetaminophen at least once a week. A significant minority were unaware of the potential liver toxicity of acetaminophen (24%), and knowledge of hepatotoxicity did not vary with education status. In terms of the medicinal composition of acetaminophen products, over half of the respondents (58%) did not know that extra strength preparations of acetaminophen contained the same drug but in a different dose. This knowledge was more prevalent among those with higher level of education (49% in graduate school educated respondents), but was still low overall. The knowledge that alcohol use with acetaminophen was more harmful was low (43%), but improved with level of education (P for trend 0.03). Among respondents who consumed alcohol regularly, 21% were consuming over 1.5 grams of acetaminophen at a time. These patients had similar harm perception to liver as patients who consumed lower doses of acetaminophen. Overall, in a large, well-educated cohort of patients, knowledge about the adverse effects of acetaminophen, the additional risks with alcohol and composition of various retailed products was suboptimal. We speculate that consumer ignorance is a significant reason why acetaminophen is a leading cause of acute liver failure.