L56 – Principles of Respiratory Pharmacology Flashcards by Max Kam

What are the afferent sensory nerves from the airways to the CNS?

 Periphery (airway)&raquo_space; nodose ganglion&raquo_space; CNS (brain stem)

 Periphery (airway)&raquo_space; dorsal root ganglion&raquo_space; CNS (spinal cord)

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What are the 2 efferent nerves from the CNS to the airways?

Parasympathetic nerve > Vagus

Sympathetic nerve

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Give pathway of vagus nerve from preganglionic nuclei to muscarinic receptors? (from brain stem to lungs)

Vagus:
preganglionic nuclei in brain stem&raquo_space; Release Ach to nicotinic receptors in nodose ganglion&raquo_space; post-ganglionic fibers&raquo_space; Release Ach to muscarinic receptors

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What are the 3 types of muscarinic receptors in the lungs?

 M1, M3 on:
Bronchial smooth muscle
Submucosal glands

 M2: autoreceptor

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What does the efferent parasympathetic vagal nerve innervate in the airways?

Bronchial smooth muscle (constrict)

Submocosal glands (secrete)

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What do the sympathetic nerves innervate in the airways?

Blood vessels

submucosal glands

NOT bronchial smooth muscle

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In asthma patients, which muscarinic receptor is dysfunctional?

In the parasympathetic vagal nerve ending:

M2 dysfunctions&raquo_space; all Ach released in vagal nerve to M1, M3

Normally M2 acts as autoreceptor and inhibits Ach release to M1, M3

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Give the INDIRECT pathway of sympathetic nerve from CNS to airway?

Preganglionic fibers&raquo_space; release Ach to nicotinic receptors on Adrenal medulla > secrete Adrenaline through blood circulation > binds to β2 receptors on bronchial smooth muscle > airway relaxation

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Give the DIRECT pathway of sympathetic nerve from CNS to airway?

Preganglionic neurons in sympathetic chain ganglia (T1-L2) of spinal cord > cervical thoracic ganglion > innervate submucosal glands, blood vessels

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What is the role of respiratory stimulants?

Help increase the urge to breathe in the treatment of respiratory failure

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What is the action of Doxapram (resp. stimulant)?

CNS stimulant > acts on both:

a) carotid chemoreceptors +
b) respiratory centre in brain stem

to increase respiration

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How does breathing pattern and blood gas change after taking Doxapram?

Increase respiratory rate and tidal volume

Fall in pCO2, Increase in pO2

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Route of admin for Doxapram?

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3 target patient groups of Doxapram?

Preterm infants with apnea

Old patients with sleep apnea

COPD patient with acute resp. failure

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What is the action of respiratory depressants?

Diffuses into cell membranes of nerve cells 

> > inhibits passive neuronal flux of Na+

> > stop respiration

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Name some respiratory depressants?

A BB HEN

 Antidepressants

 Barbiturates
 Benzodiazepines

 H1-histamine receptor antagonists (promethazine)
 Ethanol
 Narcotic analgesics (opioids: morphine, codeine)

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What is the risk of taking excessive respiratory depressant?

Excessive dosage = decrease sensitivity of respiration to CO2 and abolish hypoxic drive

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What receptors regulate hypoxic drive of respiration?

Peripheral chemoreceptors

@ carotid and aortic bodies

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What drugs provoke asthma?

NSAIDs: Aspirin, ibuprofen

Nonselective beta-adrenergic receptor antagonists (Beta-blockers)

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Explain how NSAIDs can lead to bronchoconstriction?

NSAIDs block cyclooxygenase in the Arachidonic acid pathway > inhibit synthesis of lipid mediators of inflammation

All Arachidonic acid directed to 5-lipoxygenase pathway to make Leukotrienes&raquo_space; potent bronchoconstrictor

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Airway smooth muscle B receptor is the same or different from heat B receptor?

Heart = B1

Airway SM = B2

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How does propanolol act on the heart and the airway?

Propanolol is a NON-selective Beta blocker

> block both B1 on heart and B2 on airway smooth muscle

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Can propanolol be used with inhaler?

Opposite action, contraindicate

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What are the 3 types of drugs used to treat coughs?

AME

Antitussive

Mucolytics

Expectorants

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Name some causes for production of cough? DE CAPU

Drug induced cough Environmental: irritant, dust, smoking... Chronic pulmonary ailments Asthma Pleural disease Upper respiratory tract infection

Name one drug for heart problems that can cause cough?

ACE inhibitor

2 types of cough?

Productive/ Congested cough (remove excess secretions) Non-productive/ Dry cough

Antitussives is only used for which type of cough?

ONLY for Non-productive/ dry cough

What is the function of Antitussives?

Suppress the intensity and frequency of coughing

What is the site of action for antitussives?

Peripheral or Central nervous system

How does antitiussive affect peripheral nervous system to decrease intensity and frequency of coughing?

DECREASE sensitivity of peripheral sensory ‘cough | receptors’ in pharynx and larynx to irritation

How does antitiussive affect Central nervous system to decrease intensity and frewquency of coughing?

DECREASE sensitivity of cough centres in medulla oblongata to peripheral stimulus >> Decrease cough reflex

Different administrations for Antitussives acting on peripheral NS?

Above larynx = Oral = use demulcent, e.g. syrups, lozenges Below larynx = Inhalation = inhale water aerosol, warm environment

What are the 2 classes of antitussives that act on the CNS? Which one is more popular?

Codein (opioid/ opiate agonist) Dextromethorphan (non-opiod) ** more popular **

Why is codein rarely recommended for children?

Addictive

What are the gross effects of codeine? good and bad effects

Produce constipation, nausea, respiratory depression Strong cough suppressant

What is the action of Dextromethorphan?

Selectively depresses the cough center in medulla oblongata

What are some side effects of Dextromethorphan?

Mild and rare:  Dizziness  Drowsiness  Nausea

Compare the adverse effects between Codeine and Dextromethorphan?

Codein = addictive, euphoria, respiratory depression, constipation Dextromethorphan = No addictive, no euphoria, no respiratory depression, no constipation

Which antitussive is over the counter, which is not?

Codein (opioid) is prescription drug Dextromethorphan is OTC

What is the function of expectorants?

Act locally to help remove secretions/ exudates from the trachea, bronchi, lungs

How do expectorants change the mucus and affect the CNS?

Stimulate mucin secreting cells: Produce increased volume of thinner mucin with high water content (low viscosity) Increased mucin > Stimulate cough centre to help clear the bronchial tract

Name one expectorant

Guaifenesin (OTC)

Compare the action between expectorants and mucolytics on mucus? *think volume*

Mucolytics = decrease viscosity of mucus but **Not change volume of mucus** Expectorants = Decrease viscosity of mucus BY CHANGING VOLUME

Explain the action of Mucolytics on mucus?

Break disulphide bonds cross-linking mucus glycoprotein molecules >> thinner mucin > easier to clear

Why is mucolytics especially good for bronchitis patients?

Bronchitis patients produce very thick sputum with many polysaccharide fibres

Name 3 mucolytics? NBC

N-acetylcysteine (oral) Bromhexine Carbocisteine

What is Dornase Alpha?

Recombinant human deoxyribonuclease I

Why is Recombinant human deoxyribonuclease I (dornase alpha) used for patients with cystic fibrosis? (think DNA)

CF > DNA leak out of dead neutrophils makes mucin very thick and tenacious >> Viscous purulent exudate Dornase Alpha has rhDNase I to hydrolyze extracellular DNA in mucus >> decrease viscosity

Name the 2 types of pulmonary surfactants and give an example for each?

Natural surfactant = Curosurf | Synthetic surfactant = Colfosceril

Action of pulmonary surfactant?

Decrease surface tension of alveoli > prevent alveoli collapse

How are pulmonary surfactants administered?

Endotracheal tube directly into pulmonary tree

When are pulmonary surfactants used?

Management of respiratory distress syndrome (esp. premature babies)

What is oxygen therapy used for and what is the threshold in PaO2 for starting it?

Used in the management of acute pulmonary disorders, Chronic obstructive diseases Used when PaO2 falls below 55mmHg/ 7.3kPa

What are the 2 effects of drugs used to treat COPD?

Dilate airway smooth muscle Inhibit airway inflammation

What type of HS is allergic rhinitis?

Type I

Describe the symptoms caused by allergic rhinitis?

nasal congestion, itching, redness, sneezing, runny nose, teary eyes

What is the drug used for allergic rhinitis and what is the action?

H1 Antihistamines (H1 receptor antagonist) Block histamine released by Mast cells from receptor >> stop vasodilation and stop increased capillary permeability

Name 2 first generation H1 antihistamines and name the side effects? CD

 Chlorphenamine  Diphenhydramine Sedative/ drowsiness/ dizziness Hypotention and dry mouth

Why is the second generation of H1- antihistamines non-drowsy?

2nd gen. works peripherally to block action of histamine **NEVER CROSSES BBB

Name the three 2nd generation H1 Antihistamines and name which ones are OTC or not. CLF

 Cetirizine OTC  Loratadine OTC  Fexofenadine : potent, effective,prescription

What are some other effects of 2nd generation H1 Antihistamines apart from treating allergic rhinitis?

Anti- nausea | anti-emetic, local anaethesia (if high dose)

What is the function of decongestants?

Reduce congestion of nasal passages >> open clogged nasal passages, enhances drainages of sinuses

What are the 2 decongestants? PP

Phenylephrine > selective α1-adrenergic agonist Pseudoephedrine > sympathomimetic drug

What is the action of Phenylephrine ?

Constrict dilated arterioles in nasal mucosa and reduces airway resistance

2 forms of phenylephrine? Compare their onset and systemic effects?

 Aerosol: rapid onset of action, few systemic effects  Oral: longer duration, more systemic effects

Name one combo therapy (1 pellet containing 2 classes of respiratory drug)

cetirizine (2nd generation antihistamine) + pseudoephedrine (sympathomimetic decongestant)

What is the function of a glucocorticoid nasal spray?

beclomethasone anti-inflammatory drug, immune suppressor

What is the function of Cromolyn sodium? When is it mostly used?

Intranasal spray > Anti-allergic mast-cell stabilizers Mostly for prophylaxis: stop mast cell degranulation to avoid allergic rhinitis

``` What drug classes do the following drugs belong to: Dextromethorphan Guaifenesin Dornase Alfa Phenylephine Chlorphenamine Doxapram ```

Dextromethorpan = non-opioid Antitussive Guaifenesin = expectorant Dornase alpfa = mucolytics Phenylephine = selective α1-adrenergic agonist decongestant Chlorpheamine = 1st gen H1 antihistamine Doxapram = resp. CNS stimulant

3 routes of administering resp. drugs?

Oral Inhalation Nasal spray (topical )

Which method of resp. drug admin. results in lowest effective dose and least side effects?

Inhalation Greatest and quickest deposition of drug into lungs

What are the 3 types of inhalation devices? Which one is most common

pressurized Metered-dose inhaler (pMDI) Dry powder inhaler (DPI): Turbuhaler and Diskhaler Nebulizer *DPI is most common

What drugs are put into pMDIs? (4) BSBF

Bronchodiators: - Short acting B2 agonist - Salmeterol Steroid: - BDP/ budesonide - Fluticasone

Compare the propellant in pMDI and DPI? Which needs coordinated inhalation?

pMDI = CFC profellant, need coordinated inhalation DPI = no propellant, no need for coordinated inhalation

Which type of drug delivery system is not great for patients with low Peak Expiratory Flow Rate?

Dry powder inhaler | Problem in patients with low PEFR (<60L/min)

What is the site of pulmonary absorption via inhalation?

Pulmonary epithelium, mucosa of respiratory tract

What are some advantages of pulmonary absorption via inhalation? Disadvantages?

 Advantages: fast at site of action, avoid hepatic first pass  Disadvantages: poor to regulate doses, cumbersome, local irritation (e.g. dry cough, dry mouth)

What are some advantages of drug intake via oral route?

 Advantages: easy  Disadvantages: hepatic first pass, possible GI irritation (e.g. diarrhea) .... etc

L56 – Principles of Respiratory Pharmacology Flashcards

(79 cards)