Which of the following is NOT a known side effect associated with Phenelzine use?

• A. Angle closure glaucoma
• B. Nystagmus
• C. PSC formation
• D. Lethal Hypertensive crisis

Answer: (C)

Phenelzine is an MAO inhibitor, so its adverse effects center on excessive monoamine levels and potential interactions with dietary tyramine or serotonergic drugs. The most well-known dangerous reaction is a hypertensive crisis if tyramine-containing foods are consumed, because MAO inhibition prevents breakdown of tyramine and leads to a surge of norepinephrine. That makes a lethal hypertensive crisis a known risk with this drug.

Ocular or other motor effects described in the options aren’t typical or well-established adverse effects of phenelzine. Nystagmus and angle-closure glaucoma aren’t classically linked to MAO inhibitors in standard clinical knowledge. Posterior subcapsular cataract formation is something primarily associated with long-term corticosteroid use or aging, not with MAO inhibitors. Therefore, posterior subcapsular cataract formation is the correct choice as not being a known side effect of phenelzine.