Which 2nd generation H1 blocker can cause abnormal EOM contractions known as oculogyric crisis?

Which 2nd generation H1 blocker can cause abnormal EOM contractions known as oculogyric crisis?

• A. Loratadine
• B. Diphenhydramine
• C. Brompheniramine
• D. Cetirizine

Answer: (D)

Oculogyric crisis is an acute dystonic reaction affecting the eye muscles, a type of extrapyramidal symptom that can happen when drugs at the central nervous system influence dopamine signaling or have notable CNS activity. Second-generation antihistamines are designed to have less brain activity, but among these options, cetirizine has relatively higher central nervous system penetration. That means, in rare cases, it can be associated with extrapyramidal-like reactions such as oculogyric crisis. The other second-generation option tends to have even less CNS penetration, making such reactions much less likely. The first-generation antihistamines listed cross the blood–brain barrier widely and produce many CNS effects, but their profile is not typically associated with this specific dystonic reaction in practice. So, cetirizine is the best pick because its comparatively greater CNS activity among the listed agents carries a (rare) potential for oculogyric crisis.

Oculogyric crisis is an acute dystonic reaction affecting the eye muscles, a type of extrapyramidal symptom that can happen when drugs at the central nervous system influence dopamine signaling or have notable CNS activity.

Second-generation antihistamines are designed to have less brain activity, but among these options, cetirizine has relatively higher central nervous system penetration. That means, in rare cases, it can be associated with extrapyramidal-like reactions such as oculogyric crisis. The other second-generation option tends to have even less CNS penetration, making such reactions much less likely. The first-generation antihistamines listed cross the blood–brain barrier widely and produce many CNS effects, but their profile is not typically associated with this specific dystonic reaction in practice.

So, cetirizine is the best pick because its comparatively greater CNS activity among the listed agents carries a (rare) potential for oculogyric crisis.