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Symdeko Side Effects

Generic name: ivacaftor / tezacaftor

Medically reviewed by Last updated on Mar 3, 2023.

Note: This document contains side effect information about ivacaftor / tezacaftor. Some dosage forms listed on this page may not apply to the brand name Symdeko.

Applies to ivacaftor / tezacaftor: oral tablet.

Serious side effects of Symdeko

Along with its needed effects, ivacaftor/tezacaftor may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking ivacaftor / tezacaftor:


Incidence not known

  • Blindness
  • blurred vision
  • chest tightness
  • cough
  • dark urine
  • decreased vision
  • difficulty swallowing
  • dizziness
  • fast heartbeat
  • hives, itching, skin rash
  • light-colored stools
  • loss of appetite
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • trouble breathing
  • yellow skin or eyes

Other side effects of Symdeko

Some side effects of ivacaftor / tezacaftor may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

  • Stuffy nose

For Healthcare Professionals

Applies to ivacaftor / tezacaftor: oral tablet.


The most commonly reported side effects have included headache, nasopharyngitis, nausea, sinus congestion, and dizziness.[Ref]

Nervous system

Very common (10% or more): Headache (14%)

Common (1% to 10%): Dizziness


Frequency not reported: Non-congenital lens opacities


Common (1% to 10%): Sinus congestion


Common (1% to 10%): Nausea

Uncommon (0.1% to 1%): Distal intestinal obstruction syndrome


Common (1% to 10%): Transaminase elevations

The incidence of maximum transaminase (ALT or AST) elevations to greater than 8 times the upper limit of normal (8 x ULN), greater than 5 x ULN, or greater than 3 x ULN was similar between drug treated and placebo treated patients (0.2%, 1%, 3.4% versus 0.4%, 1%, 3.4%, respectively). A total of 3 patients in clinical trials permanently discontinued therapy due to elevated transaminases (1 drug treated and 2 on placebo). No drug-treated patient experienced a transaminase elevation greater than 3 x ULN associated with elevated total bilirubin greater than 2 x ULN.

Frequently asked questions


1. Product Information. Symdeko (ivacaftor-tezacaftor). Vertex Pharmaceuticals. 2022.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.