Bronchodilators are drugs used to relieve bronchospasms associated with respiratory disorders. The main classes of bronchodilators include adrenoceptor agonists like selective beta2 agonists, antimuscarinic bronchodilators, xanthine derivatives, and leukotriene antagonists. Beta2 agonists work by stimulating beta2 receptors in the lungs to promote bronchodilation. Antimuscarinics block acetylcholine's bronchoconstrictive effects. Xanthines like theophylline inhibit phosphodiesterase to increase cAMP and cause bronchodilation. Leukotriene receptor antagonists suppress the bronchoconstrictive effects of leukotrienes. Corticosteroids

1. BRONCHODILATORS
Dr.ZIKRULLAH

2. Bronchodilators
• Drugs used to relieve bronchospasms associated with
respiratory disorders
• Includes:
– Adrenoceptor agonists
• Selective β2-agonists & other adrenoceptor
agonists
– Antimuscarinic bronchodilators
– Xanthine derivatives
– Leukotriene antagonist
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4. • Adrenoceptor agonists
– (i) Selective beta2 agonists
• Stimulate beta2 receptors in smooth muscle of
the lung, promoting bronchodilation, and
thereby relieving bronchospasms
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6. Drug Formulation Dosage
Adult Child
Salbutamol Oral tablet 8 mg twice daily 4 mg twice daily
Inhaler (MDI), 100mcg/dose 100-200mcg up to three to
four times daily
Same as adult
Syrup, 2mg/5ml 4 mg three to four times
daily
1-2 mg three to four times
daily (≥2 yr)
Terbutaline Oral tablet (S.R) 5-7.5 mg two times daily -
Inhaler 500mg / dose
( Turbuhaler)
500 mcg up to four times
daily
-
Inhaler 250mg / dose (MDI) 250-500mcg up to 3-4 times
daily, .04mg/kg sc
Same as adult
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Short-acting β-2 agonists

7. Drug Formulation Dosage
Adult Child
Formoterol Inhaler 4.5mcg / dose
(Turbuhaer)
4.5-9 mcg once or twice
daily
Same as adult
Inhaler 9mcg / dose
(Turbuhaer)
Salmeterol Inhaler 25mcg / dose
(MDI)
50-100 mcg twice daily Same as adult
50 mcg / dose (Accuhaler) 50 mcg twice Same as adult
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Long-acting β-2 agonists

9. SIDE EFFECTS OF β2 AGONISTS
• Tremor (β2-receptors in skeletal muscles)
• Tachycardia (reflex tachycardia and direct stimulation
of β2-receptors in the heart)
• Transient decrease in arterial oxygenation (relaxation
of compensatory pulmonary vascular
vasoconstriction in areas of decreased ventilation)
• Acute metabolic responses (hyperglycemia,
hypokalemia, hypomagnesemia, not present with
chronic treatment)
• Lactic acidosis

10. Drug-Drug Interactions

12. – (ii) Other adrenoceptor agonists
• Less suitable & less safe for use as bronchodilators
because they are more likely to cause arrhythmias .
• Adrenaline (epinephrine) injection is used in the
emergency treatment of acute allergic and
anaphylactic reactions
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13. • Antimuscarinic bronchodilators
– Blocks the action of acetylcholine in bronchial
smooth muscle, this reduces intracellular GMP, a
bronchoconstrictive substances.
– Used for maintenance therapy of
bronchoconstriction associated with chronic
bronchitis & emphysema
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14. Drug Formulation Dosage
Adult Child
Ipratropium Inhaler 20 mcg / dose
(MDI)
20-80 mcg three to four
times a day
20-40 mcg three to four
times a day (≥6yrs)
Tiotropium Inhaler 18 mcg /dose 18 mcg daily Not recommended in
children and adolescents
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15. • Adverse effects:
– Dry mouth
– Nausea
– Constipation
– Headache
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16. Combination Therapy
• Ipratropium+albuterol (DuoNeb®, generic)
[0.5 mg+3 mg# per 3 ml] 3 ml 6 times per day

17. • Xanthine Derivatives
– Main xanthine used clinically is theophylline
– Theophylline is a bronchodilator which relaxes smooth
muscle of the bronchi, it is used for reversible airway
obstruction
– One proposed mechanism of action is that it acts by
inhibiting phosphodiesterase, thereby increasing cAMP,
leading to bronchodialtion
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18. Drug Formulation Dosage
Adult Child
Theophylline Tablet 200 / 300 mg
(S.R.)
200 – 300 mg twice daily 10 mg / kg ((≥2yrs) twice
daily
Capsule 50 / 100 mg
(Slow release)
7-12 mg/ kg / day in two divided
doses
10-16 mg / kg / day in two
divided doses (9–16yrs)
13-20 mg / kg / day in two
divided doses (30 months – 8
yrs)
Syrup 80 mg / 15 ml 25 ml q6h 1 ml / kg (Max 25 ml) q6h
(≥2yrs)
Aminophylline Injection 25 mg / ml
10 ml
500 mcg / kg / hr IV infusion,
adjust when necessary
1 mg / kg /hr (6 months – 9
years)
800 mcg / kg /hr (10 – 16 yrs)
IV infusion, adjust when
necessary
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20. –Adverse effects:
• Toxicity is related to theophyline levels (usually 5-15
µg/ml)
• 20-25 µg/ml : Nausea, vomiting, diarrhea, insomnia,
restlessness
• >30 µg/ml : Serious adverse effects including
dysrhythmias, convulsions, cardiovascular collapse
which may result in death
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21. • Bronchodilators are sympathomimetics and commonly
interact with volatile anesthetics to cause cardiac
arrhythmias.
• Aminophyllin commionly interact with halothane.
• It is advisable to wait 13 hrs(approx 3 half lives)after
the last dose of aminophyllin before using halothane
for an asthmatic patient.
• Use of another anaesthetic (enflurane, isoflurane,
sevoflurane) decreases this problem
• The combination of Theophyllin and ketamine may
predispose the patient to seizures.
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22. Corticosteroids
1.Used for prophylaxis of chronic asthma
2.Suppressing inflammation
 Decrease synthesis & release of inflammatory mediators
 Decrease infiltration & activity of inflammatory cells
 Decrease edema of the airway mucosa
3.Decrease airway mucus production
4.Increase the number of bronchial beta2 receptors & their
responsiveness to beta2 agonists
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23. Drug Formulation Dosage
Adult Child
Beclomethasone Inhaler 50 mcg / dose
(MDI)
200 mcg twice daily /
100mcg three to fours
times daily
Up to 800 mcg daily
50 – 100 mcg two to four
times daily
Inhaler 250 mcg / dose
(MDI)
500 mcg twice daily / 250
mcg four times daily
Not recommended
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24. Drug (Cont’d) Formulation Dosage
Adult Child
Budesonide Inhaler 50 mcg / dose
(MDI)
200 mcg twice daily
Up to 1.6 mg daily
50 – 400 mcg twice
daily
Up to 800 mcg daily
Inhaler 200mcg / dose
(MDI)
Inhaler 100 mcg / dose
(Turbuhaler)
200-800 mcg once daily
in evening
Up to 1.6 mg daily in
two divided doses
200-800 mcg daily in
two divided doses /
200-400 mcg once
daily in evening
(<12 yrs)
Inhaler 200 mcg / dose
(Turbuhaler)
Inhaler 400 mcg / dose
(Turbuhaler)
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25. Drug (Cont’d) Formulation Dosage
Adult Child
Fluticasone Inhaler 25mcg / dose (MDI) 100 – 1000 mcg
twice daily
50-100 mcg twice daily
(4-16 yrs)
Inhaler 50 mcg / dose (MDI)
Inhaler 125 mcg / dose (MDI)
Inhaler 250 mcg / dose (MDI)
Inhaler 50 mcg / dose (Accuhaler)
Inhaler 100 mcg / dose (Accuhaler)
Inhaler 250 mcg / dose (Accuhaler)
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26. • Adverse effects
– Inhaled corticosteroids:
• Candidiasis of the mouth or throat
• Hoarseness
• Can slow growth in children
• Adrenal suppression may occur in long-term, high
dose therapy
• Increases the risk of cataracts
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27. • Perioperative systemic steriods should be administered
to the patients of bronchial asthma if symptoms persist
and PEFR and FEV1 is less than 80% of predicted.
• HPE suppression should be assumed to be present in
the patients who have received systemic steroid for
more than 3 weeks in the past six months.
• These should receive stress dose coverage( inj Hydrocot
100 mg iv 8 hrly with rapid tapering after 24 hrs.
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28. Anaesthetics bronchodilator
• Halothane
• Sevoflurane
• Isoflurane
• Desflurane
• Enflurane
• Propofol

29. Cromoglycates
• Stabilise mast cells & prevent the release of
bronchoconstrictive & inflammatory substances when
mast cells are confronted with allergens & other stimuli
• Only for prophylaxis of acute asthma attacks
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30. Drug Formulation Dosage
Adult Child
Cromoglycate Na Inhaler (1 mg
& 5mg/dose)
10 mg four times daily, may be
increased to six to eight times
daily
Same as adult
Nebuliser
solution 10 mg
/ ml 2 ml
20 mg four times daily, may be
increased six times daily
Same as adult
Nedocromil
Sodium
Inhaler 2 mg /
dose (MDI)
4 mg two to four times daily Sames as adult (>6
yrs)
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31. Adverse effects
Transient Bronchospasm A selective β2 agonist such as
salbutamol or terbutaline may
be inhaled a few minutes
beforehand
Others: coughing, throat irritation
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32. Leukotriene receptor antagonists
• Act by suppressing the effects of leukotrienes,
compounds that promote bronchoconstriction as well
as eosinophil infiltration, mucus productions, & airway
edema
• Help to prevent acute asthma attacks induced by
allergens & other stimuli
• Indicated for long-term treatment of asthma
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33. • Dosage:
– Montelukast (5 & 10 mg tablets)
• Adult: 10 mg daily at bedtime
• Child:
– (2-5yrs) 4 mg daily at bedtime
– (6-14yrs) 5 mg daily at bedtime
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34. • Adverse effects:
– GI disturbances
– Hypersensitivity reactions
– Restlessness & headache
– Upper respiratory tract infection
– Manufacturer advises to avoid these drugs in
pregnancy & breast-feeding unless essential
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35. Thank you
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