COPD meds

                                               Disease process: COPD

The COPD Foundation classifies Chronic Obstructive Pulmonary Disease (COPD) as an "umbrella term used to describe progressive lung diseases including emphysema, chronic bronchitis, and refractory (non-reversible) asthma. This disease is characterized by increasing breathlessness". Next, we will discuss common medication regimens used in the treatment of COPD. 

1. Use of each class, mechanism of therapeutic action and expected response

                                                           Bronchodilators 

Class: B2 agonists

mechanism of therapeutic action: cause airway smooth muscle relaxation by stimulating adenyl cyclase to increase the formation of cyclic adenosine monophosphate (cAMP).

expected response: relaxation of bronchial smooth muscle, leading to bronchodilation

Class: anticholinergics

mechanism of therapeutic action: produce bronchodilation by competitively blocking muscarinic receptors in bronchial smooth muscle.  This activity blocks acetylcholine, with the net effect of a reduction in cyclic guanosine monophosphate.  

expected response: bronchodilation and decreased mucus secretion

Class: methylxanthines (including theophylline and aminophylline)

mechanism of therapeutic action: nonspecific phosphodiesterase inhibitors increase cAMP within airway smooth muscle resulting in bronchodilation.

expected response: modest bronchodilator effect due to multiple drug interactions and narrow therapeutic index

                                                          Anti-inflammatory drugs 

Class: Corticosteroids

mechanism of therapeutic action: reduces capillary permeability to decrease mucus, inhibition of release of proteolytic enzymes from leukocytes, inhibition of prostaglandins

expected response: decreased number of exacerbations per year, improved health status, anti-inflammatory effect

Class: Phosphodiesterase-4 Inhibitors  

mechanism of therapeutic action: inhibits PDE4 leading to increased levels of cAMP and the reduction of inflammation, but does not cause bronchodilation

expected response: reduces exacerbations, without improvement in quality of life or mortality, anti-inflammatory effect

2. Differences within a class

Bronchodilators

Class: B2 agonists

Short-acting B2 agonists- used for acute symptom relief and maintenance therapy

Long-acting B2 agonists- more effective for maintenance therapy, but more expensive

Class: anticholinergics

Ipratropium- occasional metallic taste as a side effect

Tiotropium, Aclidinium- use caution in patients with Myasthenia gravis, BPH and narrow-angle glaucoma

Class: methylxanthines

Theophylline- smoking leads to increased clearance of theophylline

Aminophylline- Patients with CHF, hepatic impairment, sepsis, shock, and multi-organ failure have decreased clearance

Anti-inflammatories

Class: Corticosteroids

Inhaled Corticosteroids- vary in formulation (aerosol or powder for inhalation)  

Class: Phosphodiesterase-4 Inhibitors  

Roflumilast- only Phosphodiesterase-4 approved for the treatment of COPD. Reserved for patients not responding to the preferred therapies mentioned above. 

                                                                    

    References

Sutton, S. S. (2015). McGraw-Hills NAPLEX review guide. New York: McGraw-Hill Medical.

Take Action Today. Breathe Better Tomorrow. (n.d.). Retrieved from https://www.copdfoundation.org/