Introduction
Ondansetron is an FDA-approved selective serotonin 5-hydroxytryptamine3
(5-HT3) receptor antagonist with several therapeutic applications and is
commonly indicated as an anti-emetic agent for patients with severe
nausea and vomiting(1). Ondansetron has multiple
mechanisms of actions by blocking serotonin on central sites and
peripheral sites. Central antagonism targets the chemoreceptor trigger
zone located on the fourth ventricle floor, while peripheral action
affects the vagus nerve(2,3). As a result, the trigger
zone and the vagus nerve play a crucial role in the regulation of
serotonin and are responsible for triggering nausea and emesis
originating from the stomach(4,5). Typically,
ondansetron is indicated in patients with a history of chemotherapy,
radiotherapy, drug poisoning, antidepressant therapies, head trauma, or
gastrointestinal motility disorders that lead to symptoms of
emesis(6). A meta-analysis by Piechotta et al.
revealed that ondansetron alone or in combination with other antiemetic
agents effectively controlled the vomiting due to chemotherapy in
adults(6). However, recent studies have also shown the
efficacy of ondansetron in reducing the number of vomiting episodes in
pediatric patients with acute gastroenteritis(7, 8).
The majority of 5-HT3 receptor antagonists have been associated with
electrocardiogram changes that are insidious and asymptomatic in
onset(9). Common side effects of ondansetron include
headaches, dizziness, and diarrhea or
constipation(10). However, it is a rare entity to
observe potentially fatal reactions such as coronary vasospasms and
hypersensitivity skin reactions from ondansetron despite having no
allergies to the drug. In this paper, we present a rare case of an
anaphylactoid reaction with spontaneous coronary vasospasms in response
to intravenous ondansetron.