PTA: Cystic Fibrosis: Hereditary Disease of the Lungs and Pancreas

US Pharm. 2021;(46):15-16.

Cystic fibrosis (CF) is an inherited disease in which a mutation in the CFTR gene develops a defective protein. This defective protein causes body fluids such as mucus, saliva, and digestive juices to become thick and sticky. When mucus is not thin and watery, it plugs the airways in the lungs, making it difficult to cough out. More than 2,000 mutations of the CFTR gene are known, with the most common being the F508del mutation. In the United States, about 30,000 people suffer from CF, with 1,000 new cases diagnosed each year. Whereas in the past, most children diagnosed with the disease did not reach elementary school age, today patients are likely to live well into adulthood.

Managing Complications of Cystic Fibrosis

Many cases of CF are identified during the routine newborn blood screening that happens shortly after birth. If the screening test is abnormal, physicians will order additional blood tests to confirm a mutation in the CFTR gene. The “sweat chloride” test measures the level of salt in the sweat and is the gold standard for confirming the presence of CF.

The symptoms of CF can vary. Some experience serious symptoms from birth, and others have mild CF symptoms that may not be fully diagnosed for several years. Frequent cough, respiratory infections, shortness of breath, growth delays, and frequent, greasy, bulky bowel movements are the primary symptoms of CF. The increased salt in the sweat of those with CF can lead to an imbalance of electrolytes and a risk for heat exhaustion or heat stroke.

The thick, sticky mucus of CF causes problems in many systems of the body, especially the lungs and the digestive system. Chronic lung infections are common since bacteria can easily grow in the thickened mucus. The mucus also clogs the pancreatic ducts, stopping the pancreatic enzymes that break down food from entering the intestines. Without these enzymes, many nutrients cannot be adequately absorbed. Patients may have a good appetite and bulky stools but continue to lose weight. Chronic infections and long-term inflammation in the body due to CF can lead to diabetes, fatty liver disease, and even some forms of cancer.

The most common cause of death from CF is respiratory failure, a result of thick mucus that blocks airways and causes chronic lung infections and scarred lung tissue.

Treatment Options

There is no known cure for CF, but modern treatments have significantly prolonged and improved the quality of patients’ lives. Treatment focuses on keeping the lungs clear of mucus, improving lung function, preventing or fighting infections, and correcting the underlying cause of the disease.

Airway clearance techniques help to loosen the thick, sticky mucus in the lungs so it can be cleared by coughing. Keeping the lungs clear of mucus helps to improve lung function and prevent harmful bacteria from growing and causing infections. These techniques for maintaining lung function include medication to loosen mucus or open the airways, daily chest physical therapy, and antibiotics.

In 2012, the FDA approved the first of several medications that address the underlying cause of CF—the genetic mutations of the CFTR protein. Most currently available therapies contain one or more medicines in tablet or oral granules added to food or a liquid. The pills and oral granules should always be taken with a meal or snack containing fat to help the body absorb the medication properly. The approved CFTR modulators are ivacaftor (Kalydeco), lumacaftor/ivacaftor (Orkambi), and tezacaftor/ivacaftor (Symdeko). Most recently, the FDA approved Trikafta (elexacaftor/ivacaftor/tezacaftor), the first triple combination therapy available to treat those with CF and the common F508del gene mutation. Since each of these medications works for specific genetic mutations of the CFTR gene, not every person diagnosed with CF will be eligible for all available therapies.

Your pharmacist can answer any questions you may have about the medications used to manage CF.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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