BRONCHODILATORS

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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• 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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 Short-acting β-2 agonists

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 Same as adult

four times daily
Syrup, 2mg/5ml 4 mg three to four times 1-2 mg three to four times
daily daily (≥2 yr)
Terbutaline Oral tablet (S.R) 5-7.5 mg two times daily -
Inhaler 500mg / dose 500 mcg up to four times -
( Turbuhaler) daily

Inhaler 250mg / dose (MDI) 250-500mcg up to 3-4 times Same as adult

daily, .04mg/kg sc

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 Long-acting β-2 agonists
Drug Formulation Dosage

Adult Child

Formoterol Inhaler 4.5mcg / dose 4.5-9 mcg once or twice Same as adult
(Turbuhaer) daily

Inhaler 9mcg / dose

(Turbuhaer)

Salmeterol Inhaler 25mcg / dose 50-100 mcg twice daily Same as adult
(MDI)

50 mcg / dose (Accuhaler) 50 mcg twice Same as adult

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 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
Drug-Drug Interactions
– (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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• 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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Drug Formulation Dosage

Adult Child

Ipratropium Inhaler 20 mcg / dose 20-80 mcg three to four 20-40 mcg three to four
(MDI) times a day times a day (≥6yrs)

Tiotropium Inhaler 18 mcg /dose 18 mcg daily Not recommended in

children and adolescents

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• Adverse effects:
– Dry mouth
– Nausea
– Constipation
– Headache

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Combination Therapy
• Ipratropium+albuterol (DuoNeb®, generic)
[0.5 mg+3 mg# per 3 ml] 3 ml 6 times per day
• 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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Drug Formulation Dosage

Adult Child

Theophylline Tablet 200 / 300 mg 200 – 300 mg twice daily 10 mg / kg ((≥2yrs) twice
(S.R.) daily
Capsule 50 / 100 mg 7-12 mg/ kg / day in two divided 10-16 mg / kg / day in two
(Slow release) doses 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 500 mcg / kg / hr IV infusion, 1 mg / kg /hr (6 months – 9

10 ml adjust when necessary years)
800 mcg / kg /hr (10 – 16 yrs)
IV infusion, adjust when
necessary

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– 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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• 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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 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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Drug Formulation Dosage

Adult Child
Beclomethasone Inhaler 50 mcg / dose 200 mcg twice daily / 50 – 100 mcg two to four
(MDI) 100mcg three to fours times daily
times daily
Up to 800 mcg daily
Inhaler 250 mcg / dose 500 mcg twice daily / 250 Not recommended
(MDI) mcg four times daily

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Drug (Cont’d) Formulation Dosage
Adult Child
Budesonide Inhaler 50 mcg / dose 200 mcg twice daily 50 – 400 mcg twice
(MDI) Up to 1.6 mg daily daily
Up to 800 mcg daily
Inhaler 200mcg / dose
(MDI)

Inhaler 100 mcg / dose 200-800 mcg once daily 200-800 mcg daily in
(Turbuhaler) in evening two divided doses /
Up to 1.6 mg daily in 200-400 mcg once
two divided doses daily in evening
Inhaler 200 mcg / dose
(<12 yrs)
(Turbuhaler)

Inhaler 400 mcg / dose

(Turbuhaler)

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Drug (Cont’d) Formulation Dosage

Adult Child

Fluticasone Inhaler 25mcg / dose (MDI) 100 – 1000 mcg 50-100 mcg twice daily
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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• 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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• 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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 Anaesthetics bronchodilator

• Halothane
• Sevoflurane
• Isoflurane
• Desflurane
• Enflurane
• Propofol
 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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Drug Formulation Dosage

Adult Child

Cromoglycate Na Inhaler (1 mg 10 mg four times daily, may be Same as adult

& 5mg/dose) increased to six to eight times
daily

Nebuliser 20 mg four times daily, may be Same as adult

solution 10 mg increased six times daily
/ ml 2 ml

Nedocromil Inhaler 2 mg / 4 mg two to four times daily Sames as adult (>6

Sodium dose (MDI) yrs)

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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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 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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• 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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• 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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Thank you

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