asthma - bronchodilator inhalation drugs

Question 1

Clinical effects of β2-adrenoceptor agonists

Answer 1

-Bronchodilation (most effective bronchodilator)
increasing density of receptors on smooth muscle of trachea to small bronchioles
-Other effects
inhibit release of histamine and other inflammatory mediators
Reduce vascular permeability and mucosal oedema

Question 2

What is the β2-adrenoceptor agonists mechanism of action?

Answer 2

β2-adrenoceptors are coupled to stimulatory G protein. The alpha subunit of the G protein activates adenylyl cyclase, which catalyzes the production of cyclic adenosine monophosphate (cAMP). In the lung, cAMP causes a decrease in the intracellular calcium concentration which reduces Ca2+-dependent coupling of actin and myosin. In addition they activate BK channels and the Na+/ K+ ATPase pump, causing hyperpolarization or the airway smooth muscle cells. The combination of these activities leads to smooth muscle relaxation and bronchodilation.

Inhibits cholinergic neurotransmission

Question 3

What are the adverse effects of β2-adrenoceptor agonists?

Answer 3

Tachycardia and palpitations

Pulmonary vasodilatation

Question 4

What are the advantages of inhaled bronchiodilator drugs?

Answer 4

Achieve bronchodilatation with lower dose and fewer side effects

Question 5

Give examples of short acting bronchiodilators

Answer 5

Salbutamol

Terbutaline

Question 6

How long does it take for maximum effect of Salbutamol and Terbutaline?

Answer 6

Maximum effect within 30 mins

Question 7

How long does the action of Salbutamol and Terbutaline last?

Answer 7

Duration action 3-5 hrs

Question 8

How often are Salbutamol and Terbutaline used by patients?

Answer 8

Used on a “as needed” basis

Question 9

Give examples of longer-acting bronchiodilators

Answer 9

Salmeterol

Formoterol

Question 10

How long does the action of Salmeterol and Formoterol last?

Answer 10

Duration action 8-12 hrs

Question 11

How often are Salmeterol and Formoterol used by patients?

Answer 11

Given twice daily

Question 12

In what kind of patients are Salmeterol and Formoterol used?

Answer 12

They are used as adjunctive therapy in patients with chronic asthma where glucocorticoid therapy inadequate

Question 13

Give examples of Non-selective β-adrenoceptor agonists

Answer 13

Isoprenaline

Adrenaline

Question 14

In what kind of situation would Isoprenaline and Adrenaline be used?

Answer 14

Still used for acute severe asthma (STATUS ASTHMATICUS)