Oral
Acute bronchospasm
Elderly:
Inhalation
Acute severe asthma
Parenteral
Intravenous
Inhalation
Severe bronchospasm
Intravenous
Severe bronchospasm
Inhalation
Prophylaxis of exercise-induced bronchospasm
Dosage/Direction for Use
Oral Acute bronchospasm Elderly: Inhalation Acute severe asthma Parenteral Intravenous Inhalation Severe bronchospasm Intravenous Severe bronchospasm Inhalation Prophylaxis of exercise-induced bronchospasm |
Contraindications
IV (in the treatment of premature labour): Pre-existing or risk factors for ischaemic heart disease, gestational age <22 wk, conditions in which prolongation of pregnancy is hazardous (e.g. severe toxaemia, intrauterine infection, vag bleeding resulting from placenta praevia, eclampsia or severe preeclampsia, placental abruption, cord compression; use in threatened abortion.
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Special Precautions
Hyperthyroidism, myocardial insufficiency, arrhythmias, susceptibility to QT-interval prolongation, HTN, DM, glaucoma, hypokalaemia, seizure disorder. Renal impairment. Elderly. Pregnancy and lactation. Monitoring Parameters Monitor BP, heart rate, electrolyte and fluid balance; glucose, lactate and K levels.
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Adverse Reactions
Tremor, nervousness, nausea and vomiting, tachycardia, palpitations, chest pain, shakiness, dizziness, headache, insomnia, inhalation site sensation, hyperactivity, HTN, hypotension, increased sweating, allergic reactions, DM, muscle cramps, flu-like syndrome, conjunctivitis, UTI, hypokalaemia,. Rarely, erythema multiforme, Stevens-Johnson syndrome.
Potentially Fatal: Paradoxical bronchospasm. |
Overdosage
Symptoms: Tachycardia, CNS stimulation, tremor, hypokalaemia, hyperglycaemia, lactic acidosis, nausea, vomiting. Management: Symptomatic and supportive treatment. May administer activated charcoal. β-blocking agents (e.g. metoprolol) may be given but w/ extreme caution in asthmatic patients.
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Drug Interactions
Increased risk of hypokalaemia w/ K depleting agents (e.g. corticosteroid, diuretics, xanthines, digoxin). Increased uterine inertia w/ halogenated anaesth (IV). Increased risk of pulmonary oedema w/ corticosteroids. May antagonise the effect of anti-diabetics. Effects may be altered by guanethidine, reserpine, methyldopa, TCAs and MAOIs. Increased risk of CV effects w/ other sympathomimetic agents. Antagonistic effect w/ β-blockers.
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Action
Salbutamol activates adenyl cyclase, the enzyme that stimulates the production of cyclic adenosine-3', 5'-monophosphate (cAMP). Increased cAMP leads to activation of protein kinase A, which inhibits phosphorylation of myosin and lowers intracellular ionic Ca concentrations, resulting in smooth muscle relaxation.
Onset: W/in 5 min (inhalation); w/in 30 min (oral). Duration: Approx 3-6 hr (inhalation); up to 6 hr (oral). Absorption: Readily absorbed from the GI tract. Metabolism: Undergoes metabolism in the liver and in the gut wall. Excretion: Via urine (as metabolites and unchanged drug); faeces (small amounts). |
Storage
Inhalation: Store between 15-30°C. Protect from light. Intravenous: Store between 15-30°C. Protect from light. Oral: Store between 15-30°C. Protect from light. Parenteral: Store between 15-30°C. Protect from light.
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ATC Classification
R03AC02 - salbutamol ; Belongs to the class of adrenergic inhalants, selective beta-2-adrenoreceptor agonists. Used in the treatment of obstructive airway diseases.
R03CC02 - salbutamol ; Belongs to the class of adrenergics for systemic use, selective beta-2-adrenoreceptor agonists. Used in the treatment of obstructive airway diseases. |