Question

45 y/o woman on phenelzine for MDD, takes OTC medication for cold sx and develops hypertensive crisis. Which OTC medication would most likely cause this?

Answer 1

A hypertensive crisis in a patient on phenelzine for MDD can be caused by OTC cold medications containing decongestants such as pseudoephedrine or phenylephrine. These substances interact with the increased levels of neurotransmitters due to the MAOI and can lead to dangerously high blood pressure.

Step-by-step explanation:

The over-the-counter (OTC) medication most likely to cause a hypertensive crisis in a 45-year-old woman taking phenelzine for Major Depressive Disorder (MDD) is a decongestant containing pseudoephedrine or phenylephrine. Phenelzine is a monoamine oxidase inhibitor (MAOI), and these drugs inhibit the breakdown of neurotransmitters. This inhibition can lead to an accumulation of neurotransmitters such as norepinephrine, which in interaction with sympathomimetic drugs like pseudoephedrine or phenylephrine can precipitate a hypertensive crisis. This is due to the increased effects of these neurotransmitters on blood pressure regulation.

It is critical for patients on MAOIs to avoid certain medications and foods that can interact with their therapy. Common cold medications often contain decongestants such as pseudoephedrine or phenylephrine, which can trigger severe hypertensive episodes when combined with MAOIs. This is because the MAOI's inhibition of monoamine oxidase enzymatic activity enhances the effects of anything that releases noradrenaline or other pressor amines. Therefore, healthcare providers usually provide patients with a list of potential drug interactions and dietary restrictions to prevent such dangerous side effects.