A previously normally developing two and a half years old boy with bronchial hyperresponsiveness gradually developed apathy, flattened affect, and disinterest in communication. Neurological examination was unremarkable. Symptoms appeared after dosage of montelukast was increased. Concurrent administration of inhaled salmeterol and fluticasone was noted, but without any dosage change over past months. Acquired hearing problem and psychosocial adversities were ruled out. Illness course also did not correspond with anaclitic depression. Patient was diagnosed with drug-induced apathy, which is rarely reported in pediatric population. His conditions precluded drug discontinuation trial. He improved dramatically with 12.5 mg per day of sertraline. Dosage was titrated per symptoms to 25 mg per day. Symptoms remitted by six months, and sertraline was discontinued by nine months. No symptoms recurred three months later. Clinicians should be aware of apathy as a side effect of montelukast. Further study on safety, efficacy, and mechanism of action of sertraline in drug-induced apathy is needed. Literature reviews on apathy are provided.

Keywords: Apathy; Montelukast; Pediatric; Sertraline

DOI: 10.35755/jmedassocthai.2022.07.13350

Received 26 July 2021 | Revised 16 May 2022 | Accepted 19 May 2022