CLL Treatment: The Side Effects to Expect & Why Reporting All New Symptoms is Crucial

She shared a story about a chronic lymphocytic leukemia (CLL) patient who told her about a developing symptom he was experiencing while taking a type of targeted therapy known as BTK (Bruton’s tyrosine kinase) inhibitors. At the time, around 2016, the drug was being tested in phase 1 trials — and doctors weren’t aware of all potential side effects.

Two to three years into treatment, the patient developed high blood pressure (hypertension). At the time, Dr. Barrientos told him it likely wasn’t related to the drug, explaining that this side effect had not yet been reported in the medical literature.

“I told him that it was not the drug because we had never reported this,” she explains. “…he said no. Nobody in my family has ever had hypertension. I play basketball every other day with my friends, I’m very active, I haven’t changed my diet. This is the drug. It took us another year to realize that hypertension was a real side effect from these drugs.”

BTK Inhibitors: Monitoring Side Effects

Now that doctors understand much more about how BTK inhibitors affect patients, hypertension is considered a known side effect.

Common side effects include:

• Stomach issues (nausea, vomiting, diarrhea)
• Easier bruising and bleeding
• High blood pressure
• Joint pain

Dr. Barrientos explains that after more data was collected linking hypertension to BTK inhibitors, she went back to the patient to acknowledge he had been right.

“I’ve learned a lesson, and I’ll never doubt the patient again,” Dr. Barrientos recalls telling him, adding that a side effect can be very real for a patient even before it’s well documented in medical journals.

This is why it’s so important to make sure your concerns are heard by your doctors.

WATCH: Understanding BTK Inhibitors

If your doctor prescribes a BTK inhibitor for you, ask what to expect. Find out how the drug is likely to help you, what side effects it might cause, and what to do if you experience side effects.

Why Speaking Up Matters

Dr. Barrientos points to a few reasons why patients may need to be their own advocates, including a fast-moving field.

CLL treatment, particularly with newer targeted drugs like BTK inhibitors, is described as changing at “an amazing pace” — fast enough that even specialists say they can’t always keep up.

Additionally, not every doctor sees CLL often. Community physicians may treat far more patients with cancers like lung, breast, or prostate cancer than CLL. Even though CLL is a common form of leukemia in adults, it’s still less common than many other cancers, which can mean less day-to-day familiarity with how quickly treatment options are changing.

Dr. Barrientos explains that patients researching online (including with AI tools) is “the new reality.”

She says that doctors typically don’t take offense when patients arrive with questions generated by AI tools like SurvivorNet’s My Health Questions, framing it as an opportunity to learn together rather than a challenge to their expertise.

If you’re undergoing treatment for CLL, be sure to track changes in your body, including anything that seems out of character for your health history (as this patient did with his family history, activity level, and diet). And consider a second opinion if you feel your doctor isn’t listening to your concerns.

Questions To Ask Your Doctor

• What side effects should I monitor for while taking a BTK inhibitor?
• Is there anything I can do to reduce side effects?
• What should I do if I experience an unexpected side effect?
• What are my options if side effects become too difficult?

Learn more about SurvivorNet's rigorous medical review process.

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