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 , .

Medical Therapy

Goal of Therapy

• 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.

Oxygen therapy

• COPD patients commonly have hypoxemia {PaO2 (partial pressure of oxygen in arterial blood) of < 55 mm Hg or oxygen saturation of less than 90%}

• Oxygen administration reduces mortality rates in patients with advanced COPD because of the favorable effects on pulmonary hemodynamics.

• Trials have shown long-term oxygen therapy (15-19 hours/day) to improves survival in advanced COPD patients and thus long term oxygen therapy for hypoxemic patients (paO2 < 55 mm Hg), patients with polycythemia and paO2 < 59mm Hg or cor pulmonale is recommended. These patients require re-evaluation in 1-3 months whether they require long term oxygen therapy or not.

• Home oxygen supplementation are also recommended for patients who are well at rest but develop hypoxemia during exertion.

• Oxygen therapy generally is safe. Oxygen toxicity from high inspired concentrations (>60%) is well recognized. Additionally, lot of concerns have been there on carbon dioxide retention caused as a result of decreased respiratory drive due to increased oxygen concentration. This complication can be best avoided by maintaining PaO2 at 60-65 mm Hg
• The major physical hazards of oxygen therapy are fires or explosions thus patients, and others must be warned not to smoke.

• Route - Nasal canula. Advantages of nasal canula are -
  • It is simple and well tolerated
  • A liter of oxygen increases 3-4% of FiO2 (fraction of inspired oxygen)
  • Nasal oxygen delivery also is beneficial for most mouth-breathing patients.
  • Humidification generally is not necessary when the patient receives oxygen by nasal cannula at flows of less than 5 L/min.
• Noninvasive positive-pressure ventilation (NIPPV) advantages -
  • It allows the delivery of positive-pressure ventilation without the use of an endotracheal tube.
  • It has a tight-fitting nasal or facial mask that is attached to a continuous positive airway pressure (CPAP) or a bilevel positive airway pressure (BiPAP) machine.
  • The positive pressure is beneficial in hypercapneic respiratory failure by decreasing the work of breathing
  • NIPPV has been shown to decrease the need for endotracheal intubation, duration of hospital stay, morbidity and mortality.
  • Contraindication for use
    • Patients unable to protect airway
    • Hemodynamically unstable
    • Have significant secretions
    • Uncooperative
    • Acute Physiology and Chronic Health Evaluation (APACHE) score of greater than 29.
• The Canadian Critical Care Trials Group and the Canadian Critical Care Society Noninvasive Ventilation Guidelines Group issued guidelines (2011) encourages use of NIPPV or CPAP for patients in acute care with respiratory failure. Some of the important NIPPV facts are-
  • NIPPV should be the first-line choice for supporting patients with a severe exacerbation of COPD.
  • Routine use of helium-oxygen is not recommended with NIPPV in patients with severe exacerbation of COPD.
  • Close patient monitoring and 24-hour availability of an experienced rescue team in case noninvasive ventilation fails and rapid intervention is required.

Smoking cessation

• Smoking cessation is one of the most important therapeutic intervention for COPD.

• Most patients with COPD have a history of smoking.

• Behavioral counseling (< 10 min) and pharmacotherapy are each effective alone. However, they have synergistic effect together.

• Supervised use of pharmacologic agents is an important adjunct to self-help and group smoking cessation programs.

• Nicotine addiction is quite strong and cessation at times is difficult. Withdrawal from nicotine may cause unpleasant adverse effects, like anxiety, irritability, difficulty concentrating, fatigue, drowsiness, depression, and sleep disruption.

• If a smoker requires cigarette as an eye opener thing in the morning (within 30 minutes of waking), the individual is considered to be highly addicted and would benefit from nicotine replacement therapy.

Nicotine replacement therapies

Nicotine polacrilex

• Trade name - Nicorette, Nicorette Plus
• Available doses - 2 mg, 4 mg
• Form - Oral, is a chewing gum
• Advantage - Better quit rates than counseling alone.
• An individual who smokes 1 pack per day should use 4-mg pieces.
• The 2-mg should be used by one who smokes less than 1 pack per day.
• Patients can chew hourly and also as and when needed for their initial cravings for 2 weeks.
• Gradually reduce the amount chewed over the next 3 months.

Transdermal nicotine patches

• Trade name - NicoDerm, Nicotrol, and Habitrol.
• Success rates better compared with placebo.
• Well tolerated, adverse effects are limited to local skin reactions.

Bupropion

• Class - Antidepressant
• Trade name - Zyban
• It enhances central nervous system nonadrenergic function.
• Advantage - Better results compared to placebo
• Bupropion may be effective in patients who failed to quit smoking with nicotine replacement therapy.

Varenicline

• Trade name - Chantix
• It is a partial agonist selective for alpha4, beta2 nicotinic acetylcholine receptors.
• Acts by binding to nicotinic acetylcholine receptors and produces agonist activity and preventing nicotine binding.

Vaccination

• Pneumococcal vaccine should be given to all patients older than 65 years or to patients of any age with FEV1 of < 40% of predicted.
• The influenza vaccine should be given annually to all COPD patients.

Pharmacotherapy

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.

Steroid

• Systemic (high doses intravenous) and inhaled corticosteroids act as anti-inflammatory agents and reduce the course of the disease, symptoms, treatment failure and need for additional therapy.
• The use of systemic steroids in the treatment of acute exacerbation is widely done.
• The 2011 ICSI guidelines conclude that inhaled steroids are appropriate in patients with recurrent exacerbation of COPD.
• Studies have shown inhaled corticosteroids along with long acting beta agonist to be more beneficial than inhaled steroid alone.
• Studies have shown an increased risk of pneumonia in patients treated with inhaled corticosteroids. The debate continues on the use of inhaled corticosteroids and the risk for pneumonia in patients with COPD , .
• Use of oral steroids in stable COPD patients is not encouraged due to increased adverse effects due to steroid use (hypertension, glucose intolerance, osteoporosis, fractures, and cataracts).

Antibiotics

Anti-inflammatory

• Macrolides like azithromycin have been occasionally used in treatment of COPD due to their anti-inflammatory properties , . However, due to increased incidences of hearing loss and development of antibiotics resistance with azithromycin use, it has not been used on wide scales.

Infections

• Common organism involved in acute exacerbation of COPD are S pneumonia, H. influenza, M catarrhalis and rarely P aeruginosa. Antibiotics are commonly used in the treatment of acute exacerbation or suggestive of infection. However, regular long term antibiotics used for prevention of COPD exacerbation is not encouraged.
• Doxycycline has shown superior results for clinical cure, microbiological outcome, use of open label antibiotics, and symptoms.

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

Mucolytic

• The efficacy of mucolytic agents in the treatment of COPD remains controversial.
• The oral agent N -acetylcysteine has antioxidant and mucolytic properties (decreases sputum viscosity and secretion) and is used to treat patients with COPD
• When used as an inhalational therapy, N -acetylcysteine should be administered along with a bronchodilator such as albuterol in order to counteract potential induction of bronchospasm.

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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