Chronic obstructive pulmonary disease medical therapy

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editors-In-Chief: Cafer Zorkun, M.D., Ph.D. [2], Priyamvada Singh, MBBS [3]

Overview

Treatment of COPD requires a careful and thorough evaluation by a physician. The most important aspect of treatment is avoiding tobacco smoke and removing other air pollutants from the patient’s home or workplace. Symptoms such as coughing or wheezing can be treated with bronchodilator medications like Beta 2 receptor agonist, anticholinergic drugs. The drugs used cause benefit via relaxation of smooth muscle or decreasing inflammatory factors. . Respiratory infections should be treated with antibiotics, if appropriate. Patients who have low blood oxygen levels in their blood are often given supplemental oxygen. Currently, no treatment has been found to be totally curative against COPD except lung transplant. The treatments aim to improve lung function and quality of life. The initial treatment can be done either with Beta 2 agonist or anticholinergic. Both anticholinergics or Beta adrenergic receptor agonists have proved to be equally beneficial but the combination of the two has shown synergistic effects. Long acting bronchodilators are more beneficial than short-acting ones , .

Goal of treatment

• Improve symptoms
• Reduce exacerbation
• Improve quality of life
• Improve a patient's functional capacity

General therapy

• Patient education session about the disease, a self-treatment plan for exacerbations, and a monthly follow-up call from hospital or nurse practitioner , is associated with a lower hospitalization rate and fewer emergency department visits ,
• Treatment of COPD requires a careful and thorough evaluation by a physician.
• The most important aspect of treatment is avoiding tobacco smoke and removing other air pollutants from the patient’s home or workplace.
• Patients who have low blood oxygen levels in their blood are often given supplemental oxygen.
• Oral and inhaled medications are used for patients with stable chronic obstructive pulmonary disease (COPD) to reduce dyspnea, improve exercise tolerance, and prevent complications. Symptoms such as coughing or wheezing can be treated with bronchodilators like subcutaneous medications, beta-adrenergics, methylxanthines, and anticholinergics. They act via decreasing muscle tone in small and large airways in the lungs.
• Respiratory infections should be treated with antibiotics, if appropriate.
• Nutritional support forms an integral part of management for COPD patients.

Drug therapy

Beta adrenergic receptor agonists

Short acting selective B2 agonist

• Used for symptomatic relief during acute mild, exacerbation
• Mechanism of action - Increases intracellular cyclic adenosine monophosphate via activation of B2 -adrenergic receptors on smooth muscle cells of airway and causes smooth muscle relaxation.
• These agents are less effective in COPD compared to Asthma
• Patients may not have increase in peak flows with treatment. However, it should be continued as it offers symptomatic relief.
• The inhaled route is preferred as there is less systemic absorption thus less side-effects.
• The adverse effects include tachycardia, tremors and cardiac arrhythmia.
• Drugs available are:

Albuterol, Metaproterenol, Pirbuterol

• Used for bronchospasm refractory to epinephrine.
• Route - Inhaled

Levalbuterol

• Albuterol is a racemic mixture containing both R and S enantiomer. The S enantiomer doesn't bind to Beta 2 receptor and maybe the cause of side-effects. On the other hand, levalbuterol has only active R enantiomer thus causes less side-effects.
• It is used for both treatment and prevention of bronchospasm.

Long acting beta-2 adrenergic receptor agonist

• The long acting beta 2 receptor agonist are used to alleviate chronic persistent symptoms
• They help to increase exercise tolerance, prevent nocturnal dyspnea, and improve quality of life.
• Long-acting beta-agonists include salmeterol, formoterol, arformoterol, and indacaterol.
• They all require twice-daily dosing, except for indacaterol. Bronchodilating effect lasts more than 12 hours. Indacaterol is administered once daily.

Salmeterol, Formoterol, Arformoterol

• Relieve bronchospasms.

• Facilitate expectoration, improve symptoms and morning peak flows.

• Used in addition to anticholinergic agents.

Arformoterol

• Higher potency than racemic formoterol.

Indacaterol

• Indacaterol a long-acting beta2-agonist (LABA) is used for long-term, once-daily maintenance in patients with chronic obstructive pulmonary disease (COPD) .
• It is not for use as initial therapy in patients with acute deteriorating COPD.

Anticholinergics

• Anticholinergic drugs act as a competitive inhibitor of acetylcholine and block their action on postganglionic muscarinic receptors, thus inhibiting cholinergically mediated bronchspasm and resulting in bronchodilatation.

• They block vagally mediated reflex arcs that cause bronchoconstriction.

• Reported adverse effects include dry mouth, metallic taste, and prostatic symptoms. Studies have found an increased incidence of acute urinary retention in patient above 66 years using inhaled anticholinergic medications than in nonusers .

Ipratropium

• They have similar efficacy as beta 2 adrenergic receptor agonist.
• They have a synergistic effect on broncho-dilatation when combined with beta 2 agonist.
• They have a slower onset and longer duration of action. Thus, lesser helpful in use on an as-needed basis.
• Dose - 2-4 puffs at 6-8 hour duration.

Tiotropium

• It is the only long-acting muscarinic (once daily) anti-cholinergic agent available at this time
• It has become a first-line therapy in patients with persistent symptoms.
• It is more effective than salmeterol in preventing exacerbation

Phosphodiesterase inhibitor

Xanthine derivatives (Theophylline) (non-specific)

• Causes inhibition of enzyme phosphodiesterase (non-specific) that in turn increases cyclic adenosine monophosphate (cAMP), causing the relaxation of bronchial smooth muscles.

• It is mostly used as an adjunctive agent and reserved in non-responsive patients or patients having difficulty in using inhaled agents.

• It has a narrow therapeutic index and adverse effects, like anxiety, tremors, insomnia, nausea, cardiac arrhythmia (multifocal atrial tachycardia), and seizures above the therapeutics range. Previously the recommended target range was 15-20 mg/dL. However, now it has been reduced to 8-13 mg/dL.

• It is metabolized via cytochrome P 450 system. Thus, the plasma concentration of theophylline is affected by age, cardiac status, and liver abnormalities.

Cilomilast, Roflumilast

• Second generation, selective phosphodiesterase-4 inhibitors.
• Decreases inflammatory mediators like macrophages and CD8 lymphocytes.
• Roflumilast helps in reducing exacerbations, improve dyspnea, and increase lung function in patients with severe COPD. However, Roflumilast has not gained FDA approval for clinical use, largely because of side effects including significant nausea.
• Cilomilast another drug in this class is still in preliminary clinical trials. It is administered orally and is given in 15mg dose twice daily.

Beta adrenergic receptor blocker

COPD patients have increased risks of cardiovascular diseases. However, non-selective beta blockers have been found to increase the risks of bronchospasm and thus not recommended in these patients. Interestingly, a study has shown that addition of cardioselective beta-blocker along with standard inhaled COPD treatment with beta 2 selective agonist didn't affect the pulmonary function of the patients. Additionally, it reduce COPD exacerbation, hospital admission and all causes mortality during a follow up of 4.35 years with 5977 COPD patients .

Route of therapy

• Inhaled delivery is preferred over the oral route as there is less systemic absorption via inhaled route thus less adverse effects. However, some patients may have difficulty achieving effective delivery of the medication using a metered-dose inhaler. Use of spacer or nebulizer may be beneficial in them.

GOLD recommendations for management of COPD

GOLD recommendations for management of COPD

Stage	Degree of airway obstruction	Treatment
Stage I	Mild	Influenza vaccine (decrease risk) Short acting Beta 2 receptor agonist
Stage II	Moderate	Influenza vaccine (decrease risk) Short acting Beta 2 receptor agonist Long-acting bronchodilator Cardiopulmonary rehabilitation
Stage III	Severe	Influenza vaccine (decrease risk) Short acting Beta 2 receptor agonist Long-acting bronchodilator Cardiopulmonary rehabilitation Inhaled steroids in case of frequent exacerbation
Stage IV	Very severe or moderate with evidence of chronic respiratory failure	Influenza vaccine (decrease risk) Short acting Beta 2 receptor agonist Long term oxygen therapy Lung transplant can be considered

Symptoms for admission to emergency department

• Confusion

• Lethargy

• Labored breathing (respiratory muscle fatigue)

• Blue discoloration of skin (indicating worsening hypoxemia)

• Worsening respiratory acidosis (pH < 7.30)

Trial supportive data

Use of long acting anticholinergics like Tiotropium have shown a reduction in frequency of COPD exacerbations, hospitalization and improvement in quality of life when compared with placebo , , . However, these drugs didn't show any improvement in FEV1 or mortality. Additionally, two recently conducted large randomized trials compared tiotropium (anticholinergics) with salmeterol (long acting beta agonist)and placebo. Both the studies showed increased benefits in lung function tests, symptoms and quality of life with tiotropium when compared to salmeterol , . Other studies showed tiotropium to decrease the number of exacerbation when compared with salmeterol .

External link

COPD CDC

References

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