Drugs Acting on the Respiratory System
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Transcript of Drugs Acting on the Respiratory System
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DRUGS ACTING ON THE
RESPIRATORY SYSTEM
Dr. Ragia M.Hegazy
MD CLINICAL TOXICOLOGY
Assistant professor of clinical toxicology
Faculty Of Pharmacy,
Umm Al-Qurra University
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Drugs of resp. syst
Mucoactive agents
1-Expectorant
2-Mucolytics
3-Mucokinetics
4-Mucoregulatory agents
5-Others
Cough suppressants (antitussives)
1-Peripheral antitussives
2-Central antitussives(narcotic or non narcotic)
3-Central & peripheral antitussives
Respiratory Stimulants (analeptics)
1-Specific analeptics
2-Non-specific analeptics
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MUCOACTIVE AGENTS
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Types of cough
1. Use cough: productive treated by mucoactiveagents (expectorants, mucolytics, etc)
2. Useless cough: dry, non-productive not associated with sputum and treated by
antitussive
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Mucoactive agents (dry cough ttt)
Are agents that help in airway clearance
They serve the purpose of either:
increase the ability to expectorate sputum
or
decrease mucus hyper-secretion
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Mucoactive
agents
1-Expectorant
increase volume or hydration of airway
secretion
2-Mucolytics
1-classic mucolytics(NAC- L-cysteine)
2-SCMC
3-Proteolytic enzymes
3-Mucokinetics
stimulating
ciliary activity
1-Bronchodilators
2-Ipratrobium
3-Abhesives
4-Mucoregulatory
agents
1-Anti- inflam
2-Anticholinergic
3-Macrolide antibiotics
5-Others
1-Ambroxol
2-Saline
3-Na HCO3
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Classification according to mechanism
of action
1-Expectorants: increase volume or
hydration of airway secretion
Systemic hydration no clinical effect
Classic expectorants no clinical effect
Modifier of airway water transport (being
investigated)
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2-Mucolytics: degrade polymers in secretion
A. Thiols with free sulphydryl groups (classic mucolytics)
N- Acetyl Cysteine (NAC):
Disrupts disulfide bond making mucus less resistant
NAC can be taken orally, inhalation or instillation
Side effects:
1) GIT irritation (oral)
2) Burning sensation in airways (inhalation)
3) Bronchospasm (inhalation)
4) Sulphorous taste & odor (inhalation)
L-cysteine ethyl ester hydrochloride:
Given orally
Biotransformed in liver to NAC
Used in COPD
Has no GIT side effects
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B. Thiols with blocked sulphydryl group
S- caboxymethyl cysteine (SCMC)
Does not break mucin disulfide bonds
Increases nasal mucociliary clearance in chronic sinusitis (not
in chronic bronchitis
C. Proteolytic enzymes (peptide enzymes)
They increases sputum viscidity
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3-Mucokinetics: increase mucociliary efficiency or cough efficiency
Bronchodilators: they increase cough flow in patients with airway hyperactivity e.g. b2 agonist & theophyllineciliostimulant and bronchodilator
Ipratropium bromide has no anti-mucokinetic
Abhesives: such as surfactants
Pharmacological action Decrease mucus attachment to cilia and epithelium
Increase cough and mucociliary effect
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Mucoregulatory agents: decrease the volume of airway mucus secretion
Effective in hypersecretory states (bronchorrhea and
bronchial asthma)
A. Anti-inflammatory agents: Iidomethacin &
corticosteroids
B. Anticholinergic agents
C. Macrolide antibiotics: erythromycin, clarithromycin,
and azithromycin
Long-term oral administration causes decrease in water and mucus secretion in airway
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5- Other muco-active agents
A. Bromohexine & Ambroxol
Bromohexine increases expectoration of sputum in chronic bronchitis
Ambroxol stimulates mucus secretion and causes normalization of mucus viscosity in viscid secretion
B. Saline solution (isotonic, 0.9%) water causes Bronchospasm
Uses:
For routine nebulisation therapy
Hydration of mucus
C. Sodium bicarbonate (2%): alkaline environment causes decrease in mucus elasticity
If mucus secretion increases, viscidity decreases
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Therapeutic uses of Mucoactive agents :
1. Respiratory mucostasis e.g. chronic bronchitis,
asthma & cystic fibrosis
2. Chronic sinusitis (+ antibiotics)
3. With antibiotics for treatment of airway infections
e.g. bronchiectasis
4. Prophylaxis of post-operative chest complications
5. Sputum production for diagnostic purposes e.g.
T.B.
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COUGH SUPPRESSANTS
(ANTITUSSIVES)
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Types of cough
1. Use cough: productive treated by mucoactiveagents (expectorants, mucolytics, etc)
2. Useless cough: dry, non-productive not associated with sputum and treated by
antitussive
Cough suppressants (antitussives)
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Antitussives are drugs used in the treatment of dry
cough to suppress it (reduce input of stimuli arising
from pharynx, larynx & trachea). They include:
1- Peripheral antitussives
e.g. Liquorice, steam inhalation of tincture benzoincomposite and menthol
They have soothing effect on the irritant mucus membrane
2- Central antitussives
They inhibit the cough center
May be narcotics or non-narcotics
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Narcotic antitussives:
Codeine & morphine: antitussive, analgesic, euphoric,
respiratory center depression & dependence
Pholcodeine and hydrocodone: weak addictive,
analgesic, euphoric & respiratory center depression
Non-narcotic antitussives:
1. Noscapine (natural opium alkaloid)
2. Dextromethorphan
Have no analgesic effect
No dependence
No euphoria
No respiratory center depression
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3-Central & peripheral antitussives
Benzonatate
They inhibit cough center
They inhibit pulmonary stretch receptors
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Antitussives
Peripheral antitussives
1-Liquorice lozenges,
2- steam inhalation of tincture benzoin
3-menthol
Central antitussives
1-Narcotic antitussives:
Codeine, Pholcodeine
2-Non-narcotic antitussives:
Noscapine
Central & peripheral antitussives
Benzonatate
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RESPIRATORY STIMULANTS
(ANALEPTICS)
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Respiratory Stimulants
(analeptics)
1-Specific analeptics
Naloxone with opiate toxicity
Flumazenil with BDZ toxicity
2-Non-specific analeptics
1-Direct brainstem stimulants e.g. xanthines (Theophylline)
2-Reflex brainstem stimulants Nicotine
3- Direct & reflex e.g. Doxapram
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Respiratory Stimulants (analeptics)
They are drugs stimulating the CNS especially the
brainstem. They include:
1- Specific analeptics: used when respiratory
depression is due to certain drug overdose e.g.
Naloxone with opiate toxicity
Flumazenil with Benzodiazepine toxicity
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2-Non-specific analeptics:
A. Direct brainstem stimulants e.g. xanthines
(Theophylline)
B. Reflex brainstem stimulants through stimulation of
chemoreceptors in carotid bodies & aortic arch e.g.
Nicotine
C. Direct & reflex e.g. Doxapram
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Therapeutic uses of analeptics:
1. Treatment of respiratory center inhibition
2. Treatment of cerebral cortex inhibition
Adverse effects of analeptics:
1. Tachycardia
2. Tachpnea
3. Hypertension
4. Toxic dose causes convulsions
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Contraindications of analeptics:
1. Epilepsy
2. Ischemic heart disease
3. Hyperthyroidism
4. Hypertension
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WHAT ARE THE DRUGS ACTING
ON THE RESPIRATORY
SYSTEM????
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What categories of drugs are used as
bronchodilators
Beta agonists
Methylxanthine derivatives
Anticholinergics
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Which nonselective beta agonist is
most effective as a bronchodilator
Isoprenaline (isoproterenol)
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Why are beta 2 agonists the best
drugs for bronchial asthma
Bronchodilator
And decongestant, anti-inflammatory, and
increases mucociliary clearance
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What are the side effects of beta
agonists as bronchodilators
Tachycardia **
Hypotension
Hyperglycemia
Hypokalemia
Muscle tremors
Uterine relaxation
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what is the clinical use of
leukotriene inhibitors
Orally for prophylaxis and chronic tx of
bronchial asthma in humans
Montelukast, & Zafirlukast
Zilleuton used to be used but not anymore
because it increases liver enzymes
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What is the mechanism of action of
antihistamines in BA
Act by competitive antagonism to H1
receptors
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What are uses of antihistamines
Chronic resp disease because of their effects
on the bronchial secretions
Not useful in the control of asthma
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What are antitussives
Decrease the frequency and severity of
nonproductive cough without impairing
mucociliary defenses
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What drugs are narcotic antitussives
Codeine
Hydrocodone
Morphine
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Are the narcotic antitussives
centrally acting or peripherally
acting?
Centrally acting
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What are the non narcotic centrally
acting antitussives
Dextromethorphan
Noscapine
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What are the peripherally acting
antitussives
Bronchodilators
Mucokinetics
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What are mucokinetic drugs
Drugs that facilitate the removal of secretions
from the resp tract
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What is the mechanisms of action of
mucokinetic drugs
Act by stimulating ciliary action
Act by decreasing viscosity of bronchial
secretions
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Which mucokinetic drugs act by
stimulating ciliary activity
Beta agonists
Methylxanthines
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Which mucokinetic drugs act by
decreasing viscosity of bronchial
secretions Hydration
Saline, sterile water
Increasing pH
Bicarb
Breaking the disulfide linkages in the mucus
Acetylcysteine
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What is another use for
acetylcysteine
Antidote for APAP toxicity
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What are expectorants
Drugs which increase the volume and fluidity
of resp secretions
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What are the mechanisms of action
of expectorants
Act reflexly by irritation of gastric mucosa
Cause direct stimulation
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What is the classification
decongestants
Vasoconstrictors Phenylephrine, oxymetazoline, xylometazoline,
naphazoline) ( 1 agonist), ephedrine ( & agonists
), pseudoephedrine, phenylpropanolamine (norephedrine
and oxyamphetamine)
H1 antagonists
Diphenhydramine, hydoxyzine, chlorpheniramine,
promethazine, cyproheptadine
Cromolyn sodium (intal)
Glucocorticoids