Why is topical brimonidine contraindicated in infants younger than two years?
- A It crosses the immature blood-brain barrier and causes central nervous system depression and apnoea ✓
- B It causes severe rebound ocular hypertension on withdrawal
- C It produces irreversible mydriasis in the developing iris
- D It precipitates congenital cataract when used before age two
Correct answer: A. It crosses the immature blood-brain barrier and causes central nervous system depression and apnoea
Explanation
Brimonidine is a lipophilic alpha-2 adrenergic agonist that penetrates the blood-brain barrier. In infants the barrier is immature, so systemic absorption produces somnolence, hypotonia, bradycardia, hypoventilation and apnoea, and several deaths have been reported. It is therefore avoided below two years of age. Rebound hypertension is described with intravenous clonidine infusions, not topical brimonidine, and the other effects are not recognized.
Reference: Katzung, Basic and Clinical Pharmacology, 16th ed.
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Written and medically reviewed by the StethoPrep medical team.