My Unexpected CFTR Modulator Side Effects

Advances in cystic fibrosis care have been life-changing for me, and I’m grateful to breathe easier with a CFTR modulator. However, I began to experience new issues in the past few years, and I am left wondering if it’s a side effect of the CFTR modulator or something else.

Aug. 3, 2023 | 6 min read
A selfie of Christa Lux
Christa Lux
Christa Lux smiling and grabbing her hat in front of the Grand Canyon

My journey with CF began 21 years ago. I was diagnosed shortly after I was born, when the life expectancy of a patient with CF was in the mid-30s, and that was if I was one of the “lucky” ones. Today, however, advances in CF care have been life-changing for those who once feared what their tomorrow would look like. As a 21-year-old CF patient, I am thrilled and proud to say I look forward to many tomorrows and am filled with joy just thinking about how blessed I am. Looking back just five years ago however, things were not as hopeful.

In October 2019, I was 17 years old and having serious health issues — frequent hospitalizations, dozens of antibiotics, hours of daily chest therapy, and finding every little way to improve my health that I could with little or no success.
It was my senior year of high school and I decided to do cross-country in the fall. I heard about the great benefits of running with CF, and while I saw improvements in my lung function, despite my best efforts, I still had trouble fighting off lung infections. 

I ended up in the hospital for a two-week duration to help fight off the chronic lung infection. After two weeks of IV antibiotics, I was discouraged to find out my lung function was no better when I left than it was upon my admission, and the bacteria in my lungs was still present. It was a hard truth that I was beginning to accept. For the next two months I did everything I was supposed to do to stay healthy, but in reality, I was the furthest thing from healthy. 

The next month, I had slowly been coming to terms with the fact that there’s only so much I can do, and so I put my health in the hands of God. But then, the greatest blessing and miracle of my life showed up literally at my front door: a medicine called Trikafta®. In the first couple months, I experienced all the typical side effects that I heard others with CF experienced, like daily headaches and a very productive cough that lasted a few days. I didn't mind them, however, because I was finally able to breathe with a little more ease and not fall into a full-blown coughing fit whenever I laughed too hard or talked too much.

Fast forward almost a year later, in August 2020, I began experiencing a new and persistent side effect: digestive issues. While it is impossible to pinpoint the exact cause of this symptom, it affected my daily life and, to this day, I have yet to be certain on why I have been experiencing this. What is this side effect? To be completely candid, for the past three years I have taken daily laxatives due to chronic constipation. I have seen my fair share of specialists, ER visits, and tried anything I could that might bring relief. While my lungs were feeling great, my digestive system was not doing so hot.

By December 2021, I was still experiencing chronic stomach issues, but I put them aside because I was just thankful to have healthy and working lungs. I continued making my health a priority and beginning to run again was one way to do just that. 

To be honest, finding the motivation to run was very hard. Although it was easier than it was during my senior year when I did cross-country, it was definitely still a struggle. Trikafta helped make running easier, but it still comes with plenty of challenges. There wasn't a run that I was able to complete without using my inhaler or stopping for a walking break. But regardless, I was proud to be running and even began to enjoy it. I set my stomach issues aside, stopped trying to solve them, and, instead, became content with temporary solutions. They were like a Band-Aid, not truly resolving my issues. 

Now as I’m writing this it’s June 2023 and I have been consistently running for my workouts. I want to push myself a little harder to give myself a challenge. Over the past two years, I would run a couple miles and call it good. I never made it much farther, but I was just happy to be running.

Currently, however, I have two new goals. First, I want to figure out the “why” behind my stomach issues and stop covering them with a quick fix. My second goal is to run a half marathon.

I’m not concerned with how long either of these goals take me to reach, but I am determined to continue working towards them.

I have done everything “right,” so to speak, when it comes to my gut issues, and have been back and forth about the possibility of Trikafta being the culprit. With that said, I spoke with my CF care team, and we decided it wouldn't be a bad idea if I took a break from taking Trikafta to see if it would benefit my digestive system. After only five days of not taking this medicine, I noticed a slight increase in cough, but my constipation somehow got worse. While I was only off Trikafta for five days, my care team encouraged me to begin taking it again so that my cough doesn’t get out of hand and my stomach doesn’t get any worse. 

It's hard to say whether Trikafta could be causing my chronic constipation or if there is something else going on. I rely on communication with other members of the CF community to hear other perspectives and experiences in hopes that others may help uncover an answer for me.

Interested in sharing your story? The CF Community Blog wants to hear from you.

This site contains general information about cystic fibrosis, as well as personal insight from the CF community. Opinions and experiences shared by members of our community, including but not limited to people with CF and their families, belong solely to the blog post author and do not represent those of the Cystic Fibrosis Foundation, unless explicitly stated. In addition, the site is not intended as a substitute for treatment advice from a medical professional. Consult your doctor before making any changes to your treatment.

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CF Related Health Conditions | CFTR Modulators
A selfie of Christa Lux

Christa is 21 years old and feels blessed to be part of a generation that has such great doctors, scientists, and technology that allow her to live life to the fullest. Family and friends mean everything to Christa. She has an older brother, two younger twin sisters, two loving parents, and a dog. Over the years Christa and her family have hosted many fundraisers and events to help raise cystic fibrosis awareness. Together, Christa and her family attend Great Strides each year and look forward to raising awareness at future walks as well. You can reach Christa on Instagram.

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