Certified Ophthalmic Medical Technologist (COMT) Practice Exam

What action does phenylephrine exhibit that makes it contraindicated for newborns?

1. Increases tear production

2. Inhibits ciliary body activity

3. Vasoconstriction of retinal vessels

4. Reduces blood flow

The correct answer is: Reduces blood flow

Phenylephrine is a sympathomimetic agent primarily known for its vasoconstrictor properties. In newborns, its administration can lead to significant systemic effects due to their underdeveloped cardiovascular systems. The action of phenylephrine can lead to reduced blood flow, not only locally but also potentially affecting organ perfusion. This is particularly concerning in the sensitive physiological environment of a newborn, where maintaining adequate blood flow is crucial for proper organ function and development. While the other options may describe effects of phenylephrine, they do not encapsulate the severe implications of reduced blood flow in newborns. Increasing tear production and inhibiting ciliary body activity are not major concerns compared to the risk of vascular compromise. Additionally, while vasoconstriction of retinal vessels may be relevant, the overarching risk of systemic reduction in blood flow to vital organs makes this an important contraindication in the neonatal population.