Can you really kill someone with Visine?

I’ve never tried but a woman admitted to killing her husband by poisoning him with Visine.

How exactly?
Visine contains tetrahydrozoline which is an alpha agonist for alpha-2 receptors. When taken as an eye drop, it causes the conjunctival vessels to constrict. However, when Visine is ingested, the systemic issues that arise are a result of Visine’s imidazoline receptor I-1 agonist. Symptoms of toxicity include difficulty breathing, low body temperature, slowed heart rate, seizures, and coma to name a few. And in case a patient asks, it does not cause diarrhea unlike what the movie Wedding Crashers led you to believe.