Cystic Fibrosis: Fact Sheet on Pathophysiology, Treatment, and Drugs

This fact sheet provides a comprehensive overview of cystic fibrosis (CF), a genetic condition affecting the lungs, pancreas, and other organs, leading to thick mucus buildup and lung damage. It details the normal physiology of the lungs, the pathophysiology of CF, including genetic mutations and their effects on ion transport and mucociliary clearance, and the resulting inflammatory responses and bacterial infections. The report focuses on pharmacological treatments, particularly the use of bronchodilators like Albuterol, explaining their mechanism of action, pharmacokinetics, administration, indications, contraindications, and potential drug interactions. It also highlights the relevance of this information for clinical practice, especially in nursing, emphasizing the importance of understanding the disease's pathophysiology and pharmacology for effective patient care and education. References to key research papers are also provided.

CYSTIC FIBROSIS: FACT SHEET
Introduction
Cystic fibrosis (CF) is a condition associated with the production of mucous in the lungs and pancreas. It
blocks the mucous leading to lung damage. The symptoms may vary for different individuals and it can include the
following:
 Persistent coughs with phlegm
 Wheezing or shortness of breath
 Diarrhoea or severe constipation
 Acute bronchitis
 Fatigue
 Pulmonary hypertension
 Bulky stools
 Salty skin
Normal physiology and homeostasis of the system
CF is a condition that affects the normal physiology of the lungs. Other parts of the which are affected by CF
includes respiratory system, digestive system and reproductive system. The lung is the fundamental organ of the
respiratory system and the CF patient present with many changes in the physiological structure of the lungs. CF is
characterized by viscous secretion of the exocrine glands and most of the severe pathological changes occur in tthe
lungs (Collawn & Matalon, 2014). In normal scenario, lung plays a role in facilitating gas exchange and
transporting oxygen through the alveoli into the capillaries. The lung is subdivided into several alveoli, which is the
primary organ for gas exchange. Restrictive lung disease like CF restricts lung expansion and result in decreased
lung volumes (Haddad & Sharma, 2019).

The homeostasis of respiratory system is maintained by gas exchange and regulation of the pH of
blood. The Lungs is involved in gas exchange function by eliminating carbon dioxide and inhaling
oxygen. ATP produced by cellular respiration plays a role in providing energy to the body. A
complex system of local immune pathways also maintains homeostasis in the lungs. The figure 1
below shows the homeostasis of the lungs and the factors involved in it (Lloyd & Marsland, 2017).
However, in patients diagnosed with CCF, year to year change in forced expiratory volume in one
second is seen. This results in dehydrated mucous which contributes to airway obstruction,
inflammatory response, chronic bacterial infections and eventually respiratory failure (Collawn &
Matalon,2014)..
Figure 1: Homeostatis of the lungs. Source: (Lloyd & Marsland, 2017).

Pathophysiology of the disease
CF is a disease that is caused by mutation in the CF gene which causes dysfunction of the
transmembrane conductance regular (CFTR) protein. A child must inherit two copies of defective genes
from each parent for the disease to occur. If there is only one copy of the defective gene, then the person is said
to be the carrier of the disease. This mutated genes lead to the building of thickened layers of mucous in the
lungs, liver and pancreas. CFTR has a role in regulating the movement of sodium and chrolide ions in
epithelial cells. When mutation occurs in one or both copies of the gene, the ion transport system is
disrupted. This change leads to respiratory insufficiency and systemic abnormalities resulting in the
build up of mucus and other secretory granules. Along with altered ion transport, decrease in
mucociliary clearance takes place too. This change has impact on the cells of many organs. It leads to
respiratory insufficiency as well as many other systemic obstructions in the human body.
Overwhelming inflammatory response is also activated after muco-ciliary clearance leading to
colonization of bacteria in the respiratory tract. Some examples of these bacteria include
Staphylococcus aureus, Pseudomonas and Haemophilus influenza. This form of repetitive
inflammatory response leads to airway destruction in the affected individuals. Till date, more than six
classes of CF mutation has been identified (Haack, Aragão & Novaes, 2013; Brown et al., 2017).
Figure 1: Chest radiograph showing mucous in the lungs of patient with CF Source: (Brown et al.,
2017)

Pharmacology related to the treatment of the disease
Combination of therapies is planned for the treatment of patient with cystis fibrosis. These
treatment options include use of respiratory medications given by nebulizer, airway clearance therapy
and pancreas enzyme. According to Brown et al. (2017), pharmacological management of CF is done
by anti-inflammatory drugs like ibuprofen, antibiotics and bronchodilators. Over more than 80% of
people with CF are prescribed bronchodilators to alleviate the symptoms of wheeziness and shortness
of breath. Both short acting and long acting bronchodilators play a role in opening the airways and
promoting airway clearance. Short acting bronchodilator is used for treating sudden attacks of
breathlessness within four to six hours, whereas long acting bronchodilator is useful as a maintenance
therapy (Smith & Edwards, 2017). One example of a bronchodilator used in the treatment of CF
includes Albuterol. The following is the detailed pharmacology of the drugs:
Drug naming: Albuterol belongs to the class of beta-2 agonist drug. The generic name of the drug is
Albuterol sulphate and it is also known as Salbutamol. It is mainly used for treatment of bronchospasm
in patients with lung disease like asthma and CF.
Mechanism of action: Albuterol is prescribed as a nebulizer or meter dose inhaler to patients with CF.
In patients with CF, mutation in the CF leads to thick mucus development within organs. The problem
is most severe in lungs as it makes people susceptible to infections. It works by binding to the beta-2-
adrenergic receptor in the smooth muscles of the airway. This form of binding leads to the activation
of the receptor. This further result in relaxation of the smooth muscles of the airways. Thus, symptom
of shortness of breath and wheezing is treated by this intervention (Johnson & Bounds, 2019).

Pharmacokinetics: After inhalation, this drug acts on the bronchial smooth muscles and it is
absorbed in the gut after 2-3 hours. The volume of distribution is around 150-180 L. The
metabolism of the drug takes place in the liver. After oral absorption of the drug, 60-70% of the
drug is excreted in the urine and a very small concentration is excluded in the faeces. The half life
of the drug is around 4.5 hours (Usmani et al., 2018).
Route of administration: It is inhaled orally using jet nebulizer or as an aerosol inhaled by mouth
using inhalers. People older than 12 years should be give 2-4 mg of albuterol 3-4 times daily
(Mashat et al., 2017).
Indications, contraindications and precautions: The drug is indicated for use in controlling and
preventing reversible airway obstruction caused by asthma or CF. The drug should be used with
precautions as it is contraindicated in patients with hypersensitivity to adrenergic amines. The drug
should also be used cautiously in patients with cardiac disease, diabetes, hypertension and
insomnia. The following are adverse reaction of the drugs:
 Palpitation and angina
 Nervousness or restlessness
 Nausea
 Hyperglycemia
 Hypokalemia

‘
Drug-drug interactions:
Albuterol is known to interact with other adrenergic agents. It also interacts with beta-
blockers and diuretics. Hence, review of other medications of patient should be done before giving
the drug to other patients. This will help in decreasing toxic effect due to drug-drug interactions
Other considerations for patient:
While giving Albuterol to patient, it is also necessary to educate patient regarding taking
the drug as directed by the physician. The patient must be made aware of all the adverse effects and
immediately contacting health care staffs if shortness of breath is not addressed by the drug. If any
patient is taking the drug using nebulizer, instructing patient in the proper use of this device is
necessary. The patient must cautioned regarding avoiding prolongers use of the drug too (Johnson
& Bounds, 2019).
Relevance to clinical practice:
The above information factsheet is useful for nursing field as it gives guidance on ways to
use drug for treatment of CF. The above factsheet is likely to expand knowledge of nurse in
interpreting signs and symptoms and understand ways the pathophysiology of the disease
contribute to ongoing problems for patient. Proper understanding of anatomy and physiology of the
disease can help nursing staffs to communicate about any issue at the right time. Moreover, the
information regarding the pharmacology of bronchodilator gives implication to nursing staffs
regarding the key factors to consider while providing this drug to CF patients. It also highlights the
need to give education on side-effects and proper use of nebulizers.
Conclusion
To conclude, pharmacological interventions like the use of bronchodilatos or antibiotics is
the main treatment for reducing airway obstruction in CF. The factsheet gave an overview of one
of the bronchodilators called Albuterol. Just like this drug, considering side-effect, mechanism of
action, drug-drug interaction and contraindications are important before administering any other
class of drugs to patient with CF.

References
Brown, S. D., White, R., & Tobin, P. (2017). Keep them breathing: Cystic fibrosis pathophysiology, diagnosis,
and treatment. Journal of the American Academy of PAs, 30(5), 23-27.
Collawn, J. F., & Matalon, S. (2014). CFTR and lung homeostasis. American journal of physiology. Lung cellular
and molecular physiology, 307(12), L917–L923. https://doi.org/10.1152/ajplung.00326.2014
Haack, A., Aragão, G. G., & Novaes, M. R. (2013). Pathophysiology of cystic fibrosis and drugs used in
associated digestive tract diseases. World journal of gastroenterology, 19(46), 8552–8561.
https://doi.org/10.3748/wjg.v19.i46.8552
Haddad, M., & Sharma, S. (2019). Physiology, Lung. In StatPearls [Internet]. StatPearls Publishing.
Johnson, D. B., & Bounds, C. G. (2019). Albuterol. In StatPearls [Internet]. StatPearls Publishing.
Lloyd, C. M., & Marsland, B. J. (2017). Lung homeostasis: influence of age, microbes, and the immune
system. Immunity, 46(4), 549-561.
Mashat, M., Clark, B. J., Assi, K. H., & Chrystyn, H. (2017). Assessment of recent nebulizer delivery systems
using urinary pharmacokinetics method and aerodynamic characteristics of TOBI® nebulized dose
following inhalation. Journal of Drug Delivery Science and Technology, 39, 428-434.
Smith, S., & Edwards, C. T. (2017). Long ‐acting inhaled bronchodilators for cystic fibrosis. Cochrane Database
of Systematic Reviews, (12).
Usmani, O. S., Biddiscombe, M. F., Yang, S., Meah, S., Oballa, E., Simpson, J. K., ... & Maher, T. M. (2018).
The topical study of inhaled drug (salbutamol) delivery in idiopathic pulmonary fibrosis. Respiratory
research, 19(1), 25.