Which vasoconstrictor is contraindicated (most cautioned) in patients with thyroid dysfunction such as hypothyroidism/hyperthyroidism?

Correct answer: C. Norepinephrine

• A. Epinephrine is used cautiously in low doses but is not the single 'most contraindicated' of these three.
• B. Levonordefrin is an alpha-agonist that can raise BP, but norepinephrine is the most potent pressor.
• C. Correct (keyed). Norepinephrine, the most potent pure pressor, carries the greatest hypertensive risk and is generally avoided.

Note: This is an atypically worded item; thyroid caution applies to all sympathomimetics. The keyed answer (most potent pressor) is norepinephrine.