Lumacaftor/ivacaftor, sold under the brand name Orkambi among others, is a combination of lumacaftor and ivacaftor used to treat people with cystic fibrosis who have two copies of the F508del mutation. It is unclear if it is useful in cystic fibrosis due to other causes. It is taken by mouth. Common side effects include shortness of breath, nausea, diarrhea, feeling tired, hearing problems, and rash. Severe side effects may include liver problems and cataracts. Ivacaftor increases the activity of the CFTR protein, while lumacaftor improves protein folding of the CFTR protein.