Off-label use of drugs by age in Brazilian children: a population study

To estimate the prevalence of off-label drug use by age in children 12 years old and younger in Brazil. Population-based cross-sectional study (National Survey on Access, Use and Promotion of Rational Use of Medicines - PNAUM), including 7,528 children aged 12 years or younger. Face-to-face interviews were used to collect the data in the domiciles. The age-related off-label classification was carried out using the electronic medication compendium of National Agency of Sanitary Surveillance (ANVISA). Sociodemographic characteristics, presence of chronic disease, use of health services and characteristics of the informant were collected. Data were expressed by relative frequencies and 95% confidence intervals. Pearson's chi-square test was used to evaluate the statistical significance of the differences between the groups, with a significance level of 5%. Main outcome measure was the prevalence of off-label use. The prevalence of off-label use by age was 18.7% (95%CI 16.4 - 21.3). Children younger than 2 years old presented the highest prevalence of off-label use. The most frequently used off-label drugs by age were amoxicillin, nimesulide and the combination of phenylephrine and brompheniramine. The off-label use of drugs by age is common in the Brazilian pediatric population, especially among children under two years old.