Respiratory pharmacology - drugs affecting bronchiole diameter

Question 1

Give examples of types of respiratory drugs

Answer 1

Drugs affecting bronchiole diameter
Drugs affecting respiratory centre
Anti-tussives
Decongestants
Expectorants 
Mucolytics
Surfactants

Question 2

Which 2 systems, 1 reflex and 1 receptor affect bronchial diameter?

Answer 2

Sympathetic system
Parasympathetic system
Nasopulmonary reflex
Non-adrenergic non-cholinergic receptors

Question 3

Do the symp and parasympathetic NS cause broncho dilation or bronchoconstriction? What effect do they have on mucous?

Answer 3

Sympathetic - broncho dilation, increased mucociliary clearance
Parasympathetic - bronchoconstriction and increased mucous production

Question 4

Which receptors are responsible for causing smooth muscle dilation (broncho dilation) by the sympathetic nervous system?

Answer 4

B2 adrenoreceptors

Question 5

Which receptors are responsible for parasympathetic stimulation (bronchoconstriction and increased mucous secretion)? Stimulation of which nerve is responsible for this?

Answer 5

Muscarinic receptors

Via vagus nerve

Question 6

What are the 3 broad classes of drugs affecting bronchial diameter?

Answer 6

Adrenegic drugs
Cholinergic drugs
Drugs directly acting on smooth muscle

Question 7

Adrenoreceptor agonists are adrenergic drugs. What do they stimulate and cause? What systemic adrenoreceptor agonists (neurotransmitters) are found naturally in the body?

Answer 7

Stimulate sympathetic NS and cause bronchodilation

Noradrenaline
Adrenaline

Question 8

Give an example of an adrenoreceptor agonist drug. What condition can this be given for? What are the side effects?

Answer 8

terbutaline
Acute bronchoconstriction
Peripheral vasoconstriction, tachycardia, sweating, excitement

Question 9

In which patients would you need to consider giving adrenaline to?

Answer 9

Patients with blood pressure abnormalities or tachycardia

Question 10

Using 2 adrenoreceptor agonist drugs together leads to a higher chance of side effects, as adrenoreceptor agonists usually have lots of side effects. Why?

Answer 10

Non-selective agonists

Stimulate sympathetic nervous system systemically

Question 11

Give 4 examples of adrenoreceptor agonists

Answer 11

Noradrenaline
Adrenaline
Ephedrine
Isoproterenol

Question 12

What is a property of B2 selective agonists that make them more preferable than adrenoreceptor agonists?

Answer 12

Selective - have varying range of selectivity

Therefore less side effects

Question 13

Give 3 examples of B2 selective agonists

Answer 13

Clenbuterol
Salbutamol (albuterol)
Terbutaline

Question 14

How can terbutaline and salbutamol be administered? What effect do these administration methods have on terbutaline uptake?

Answer 14

Oral - less uptake as higher pKA

Inhalation - fast and complete uptake

Question 15

How is clenbuterol administered? What is an important feature of this drug?

Answer 15

Orally

Excreted in urine for 12 days

Question 16

What effect do adrenoreceptor antagonists have on the bronchi?

Answer 16

Opposite to agonist - bronchoconstriction

Question 17

Give an example of an adrenoreceptor antagonist

What is this drug primarily used for? When might it be contraindicated?

Answer 17

Beta blockers
Treatment of tachycardia
Asthma or chronic bronchitis as causes bronchoconstriction

Question 18

What type of drugs are anticholinergics and what do they cause?

Answer 18

Parasympathetic antagonists

Bronchodilation, decreased mucous production, reduced response to irritation, pulmonary vasoconstriction

Question 19

What are the side effects of anticholinergics/parasympathetic antagonists?

Answer 19

Tachycardia 
Decreased GI motility
mydriasis
Hypertension 
Mydriasis

Question 20

Anticholinergic drugs/parasympathetic antagonists are rarely used in practice except for which drug and why? How is it administered?

Answer 20

Ipratropium

Topical administration so reduced side effects

Question 21

What effect do cholinergic drugs have?

Answer 21

Bronchoconstriction

Increased mucous secretion

Question 22

Cholinergic drugs have limited effect on respiratory system. Give 2 examples of cholinergic drugs and what are they used for?

Answer 22

Pilocarpine- topically on eye

Bethanechol - systemically for smooth muscle contraction

Question 23

How do indirect cholinergic work?

Answer 23

Inhibit AChE

Increase acetylcholine at synapse

Question 24

What class of drugs act directly on smooth muscle to affect bronchiole diameter?

Answer 24

Methylxanthines

Question 25

Describe 3 properties of methylxanthine drugs (what they do)

Answer 25

PDE inhibitors
Block degradation of cAMP
Adenosine antagonists (further increase cAMP)

Question 26

Methylxanthine drugs cause an increased level of cAMP. What effect does increased cAMP have?

Answer 26

Bronchodilation
Inhibition of inflammatory mediators
Increased mucociliary clearance (cilia beat cranial faster - to pharynx to swallow)

Question 27

Methylxanthine drugs have desirable effects for conditions such as asthma and acute bronchitis. What are the side effects of methylxanthines?

Answer 27

Tachycardia
Excitability
Seizures
Decreased GI motility

Question 28

Give an example of a methylxanthine drug. How is it administered? How is it excreted?

Answer 28

Theophylline
Oral administration
By kidneys (parent drug and metabolites)
(Also penetrates BBB)