Final answer:
Phenylephrine, ephedrine, and metaraminol can potentially interact with selegiline, a MAOI, to cause significant adverse reactions such as hypertensive crisis.
Step-by-step explanation:
Which of the following could cause significant adverse reactions with the MAO-i selegiline? From the options provided, phenylephrine, ephedrine, and metaraminol are all sympathomimetic agents that can potentially interact with selegiline, a monoamine oxidase inhibitor (MAOI), to cause significant adverse reactions such as hypertensive crisis. These substances can increase the levels of norepinephrine and other monoamines by preventing their breakdown, which in the presence of MAOIs, can lead to dangerously high levels. Therefore, strict dietary and drug interaction precautions are necessary when a patient is on MAOIs like selegiline.