Pharmacology of COPD

Question 1

What is Chronic Obstructive Pulmonary Disease (COPD)?

Answer 1

Persistent airflow limitation that’s usually progressive and associated with an enhanced chronic inflammatory response in the airways and the lung due to noxious particles or gases

Question 2

Name 2 examples of bronchodilators

Answer 2

1. B2-adrenergic agonists - SABAs and LABAs
2. Muscarinic antagonists (Anticholinergic) - SAMAs and LAMAs

Question 3

Name an example of a non-bronchodilator

Answer 3

Combined Meds - Steroids - LABA

Question 4

Characteristics of b-adrenergic agonists

Answer 4

Agonists - drugs that bind the receptors and activate the cell

B-adrenergic agonists - same effect as epinephrine, norepinephrine

Question 5

What are the 2 subtypes of B-adrenergic agonists?

Answer 5

1. Nonselective adrenergic drugs - stimulates B1 (cardiac) and B2 (respiratory) receptors
2. Selective B2 adrenergic drugs - stimulates the B2 receptors

Question 6

What are the 2 categories of B-adrenergic agonists and what drugs are associated with them?

Answer 6

1. SABAs - short-acting B2-agonists: Albuterol
2. LABAs - long-acting B2-agonists: Salmeterol

Question 7

Describe Salmeterol (SABA/LABA?, classification, pharmacology, indications, MOA, pharmacokinetics, cautious usage, adverse reactions/side effects)

Answer 7

LABA

Classification: Bronchodilator

Pharmacologic: Adrenergic

Indications: Maintenance treatment to prevent bronchospasm in COPD including chronic bronchitis and emphysema

Mechanism of action: Produces accumulation of cAMP -→ decreased Calcium → decreased muscle contraction → bronchodilation.

Pharmacokinetics:
- Half-life: Inhalation: 3-4 hours
- Onset: Inhalation: 10-25 minutes

Use cautiously in: Cardiac disease

Adverse reactions/side effects:
- Palpitations
- Tachycardia
- Headache

Question 8

Characteristics of anticholinergics

Answer 8

• Acetylcholine (ACh) receptors are found on bronchial tree – parasympathetic nervous system
• Anticholinergics block the Acetylcholine from binding to the ACh receptors
• Decreases secretions in patients with COPD

Question 9

What are the 2 categories of Anticholinergics and what drugs are associated with them?

Answer 9

1. SAMA - Short-acting muscarinic-antagonist: Ipratropium
2. LAMAs - Long-acting muscarinic antagonist: Tiotopium

Question 10

Characteristics of corticosteroids

Answer 10

They are non-bronchodilating. They are synthetic glucocorticoids that mimic the action of naturally occurring steroid hormones (ex. cortisol)

Powerful anti-inflammatory agents with many indications (arthritis, asthma)

Decreases inflammation by:
- Suppressing migration of immune cells
- Reversal of increased capillary permeability

Duration of use is limited as therapeutic doses are associated with many adverse effects

Question 11

How can you manage COPD using GOLD guidelines?

Answer 11

Aim:
- Improve patient symptoms
- Decrease exacerbations
- Improve patient function and quality of life

Selection of pharmacologic agents are based on the severity of symptoms and risk of future exacerbations

Question 12

When do you use short-acting bronchodilators for rescue bronchodilator therapy?

Answer 12

It is used by the pt as needed for the relief of acute exacerbations of COPD where there are experiences of dyspnea. SABAs and SAMAs are not prescribed as regular scheduled medications

Question 13

What happens if the pt is already on LAMAs as a maintenance therapy and is in need for rescue bronchodilator therapy?

Answer 13

We would use SABAs, not SAMAs for short-acting rescue bronchodilator. This is because SAMA and LAMA together can have a cumulative anticholinergic effect, which can increase side effects

Question 14

What if the pt is not on LAMAs and is in need for rescue bronchodilator therapy?

Answer 14

A combination of SABA-LAMA as a rescue bronchodilator is recommended. This increases bronchodilator effectiveness since:

• They work on different locations of the airways. Muscarinic antagonists work on the proximal large airways. Adrenergic agonists work on the distal small airways
• They have different mechanism of action → tackling bronchoconstriction from different points

The combination of SABA-SAMA – allows for lower doses of each to be used → less side effects associated with each

Question 15

Describe Group A pts

Answer 15

Less symptomatic pts at low risk for exacerbation

• These patients are on long-acting bronchodilators.
• Either a long-acting beta-agonist (LABA) OR a long-acting muscarinic antagonist (LAMA)
• LAMA has been shown to be more effective in preventing exacerbations
• LAMA of choice: Tiotropium
• Can give patients dry mouth or urinary retention. Therefore, patients may prefer LABA
• LABA of choice: Salmeterol
• Can give patients tachycardia or tremors. Therefore, patients may prefer LAMA

Question 16

Decribe Group B pts

Answer 16

More symptomatic pts at low risk for exacerbations

-Recommended use of dual bronchodilators – LABA-LAMA
- Inhaler with LAMA-LABA combined leads to better adherence and reduced cost, compared two separate inhalers
- LABA-LAMA: Tiotropium-Olodaterol (You do not need to know the name or specifics of the drug – just that these patients are given LABA-LAMA combination)