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
2
3.
4. • Adrenoceptor agonists
– (i) Selective beta2 agonists
• Stimulate beta2 receptors in smooth muscle of
the lung, promoting bronchodilation, and
thereby relieving bronchospasms
4
5.
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
6
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
7
Long-acting β-2 agonists
8.
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
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
12
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
13
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
14
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
17
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
18
19.
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
20
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.
21
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
22
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
23
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)
24
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)
25
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
26
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.
27
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
29
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)
30
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
31
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
32
