Trazodone Diltiazem Interaction – Case Scenario

Trazodone Diltiazem Interaction

In this scenario, I outline a situation involving the trazodone diltiazem interaction.

A 74 year old patient was recently diagnosed with atrial fibrillation. Rate control was the preferred method of management by cardiology, but unfortunately, beta-blockers were not tolerable in this patient.

Diltiazem was initiated to help improve tachycardia and manage the atrial fibrillation. It worked well, and vital signs were well maintained. Pulses were in the 60-70 range and blood pressure was fine with no indication of orthostasis symptoms.

Within a week of begginning to take the diltiazem, the patient did report that she was more fatigued. She felt as if she could “sleep all day”. Diltiazem itself could certainly be responsible for this adverse effect. What was also of note is that she was on trazodone 100 mg at bedtime for insomnia.

Trazodone Diltiazem Interaction Discussion

Diltiazem is a well known CYP3A4 inhibitor. Any medication that is broken down by this enzyme can have its concentrations rise if we inhibit this enzyme. Trazodone is one of those medications. (Here is another classic interaction with Diltiazem).

With the addition of diltiazem, this likely increased the concentrations of trazodone. One of the most common adverse effects with trazodone is sedation. With the higher concentrations, we are more likely to have made this patient more sleepy. I did mention that the diltiazem could do this is well and that has to be a consideration.

As a clinical pharmacist, it is critical to do the best we can to provide a solution (which is what I try to teach in my Medication Recommendation Webinar). In this case, the patient is well controlled with the new diltiazem Rx. I would be reluctant to switch this to another agent for atrial fibrillation. The most simple solution would be to titrate the dose of trazodone in a downward fashion and try to minimize the risk of sedation due to likely increased concentrations from the trazodone diltiazem interaction. If you’d like more practice pearls on trazodone, you can listen to my podcast on

Did you enjoy this blog post? Subscribers are emailed new blog posts TWICE per week! In addition, you’ll get access to the free giveaways below. Over 6,000 healthcare professionals have subscribed for our FREE Giveaways. Why haven’t you?!

Study Materials and Resources For Healthcare Professionals and Students – Amazon Books

1 Comment

  1. Cecilia

    Hi Eric, thanks for sharing the clinical pearl.
    I’m a pharmacy student right now and hopefully I could get my license next year. I kind of have a question on trazodone relating to my recent family doc visit.
    I have difficulty in staying asleep for 2-3 years. So my previous family doc prescribed trazodone 25mg PRN. It worked fine for me. But recently I changed to another family doc and she said she didn’t like trazodone. The reason was: “trazodone has tolerance, which means you will need higher dose to achieve the same effect”. I didn’t remember trazodone had this problem, but I wasn’t quite sure so I didn’t say anything. Then I went back home and checked my pharmacotherapy textbook and I didn’t find anything about tolerance of trazodone mentioned there. So my question is, have you ever heard such thing? Thank you very much!


Submit a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Written By Eric Christianson

March 13, 2019

Study Materials For Pharmacists


Explore Categories