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100mcg salbutamol/dose dry powder for inhalation: A mixture of microfine salbutamol (as sulphate) and larger particle lactose in a multiple dose powder inhaler (MDPI). One dose of Buventol Easyhaler® contains 100mcg of salbutamol (as sulphate) for oral inhalation. Easyhaler multidose powder inhaler contains 200 doses. Each MDPI is wrapped in aluminium foil and packed into individual cartons.
200mcg salbutamol/dose dry powder for inhalation: A mixture of microfine salbutamol (as sulphate) and larger particle lactose in a multiple dose powder inhaler (MDPI). One dose of Buventol Easyhaler® contains 200mcg of salbutamol (as sulphate) for oral inhalation. Easyhaler multidose powder inhaler contains 200 doses. Each MDPI is wrapped in aluminium foil and packed into individual cartons.
Salbutamol is a selective β2 adrenoceptor agonist. At therapeutic doses, it acts on the β2 adrenoceptors of bronchial muscle with little effect on β1 adrenoreceptors of cardiac muscle. With its fast onset of action, it is particularly suitable for the management and prevention of attack in mild asthma and for the treatment of acute exacerbations in moderate and severe asthma.
Salbutamol is readily absorbed from the gastrointestinal tract, maximum plasma concentrations occurring within 2.5 hours. It is subject to first pass metabolism in the liver. The plasma half-life ranges from 2.7-7.0 hours. Elimination occurs by both metabolism and urinary excretion. 76% of an oral dose is excreted over 3 days with the majority of the dose excreted within the first 24 hours.
Salbutamol is metabolised to a sulphate conjugate accounting for 50% of an oral dose. About half is excreted in the urine as an inactive sulphate conjugate, following oral administration (the rest being unchanged salbutamol), whereas rather less is excreted as the conjugate following intravenous administration. Unlike isoprenaline, salbutamol is not inactivated by catechol-o-methyl-transferase (COMT) or sulphatase enzymes.
After inhalation therapy, systemic absorption is low, maximum serum concentrations occurring within 2-4 hours. Salbutamol does not appear to be metabolised in the lung, therefore its behaviour following inhalation depends upon the delivery method used, which determines the proportion of inhaled salbutamol relative to proportion inadvertently swallowed.
Urinary studies indicate an elimination half-life of approximately four hours. Of that which is absorbed, 72% is excreted with 24 hours in the urine, 28% as unchanged salbutamol and 44% as the sulphate conjugate.
Salbutamol does not pass the blood-brain barrier.
Salbutamol is indicated for the treatment of mild to severe bronchospasm and reversible airways obstruction.
The preparation is intended for oral inhalation only. Salbutamol has duration of action of 4 to 6 hours in most patients. This preparation is particularly useful for patients unable to use metered dose inhaler properly and for patients to whom the use of inhalation aerosol causes irritation of airways. The lowest effective doses of inhaled salbutamol are recommended to be used in the treatment of asthma. In the long term treatment it is recommended, instead of regular use, to use inhaled salbutamol when needed.
Adults: For the relief of acute asthma or before exercise 100-400mcg. The recommended dose for maintenance treatment or prophylactic therapy is 100-400mcg three to four times a day. Maximum dose is 1.6mg/day.
Children: In the treatment of episodic asthma or before exercise 100-200mcg. The recommended dose for maintenance treatment or prophylactic treatment is 100-200mcg three to four times a day. Maximum dose is 0.8mg/day.
Salbutamol is contraindicated in-patients with a history of hypersensitivity to any of its components.
Although salbutamol and occasionally salbutamol tablets are used in the management of premature labour uncomplicated by conditions such as placenta praevia, ante-partum haemorrhage or toxaemia of pregnancy, inhaled salbutamol preparations are not appropriate for managing premature labour. Salbutamol presentations should not be used for threatened abortion.
If a previously effective or recommended dose fails to give relief, the patient should be advised to seek medical advice in order that any further necessary steps may be taken.
Salbutamol should not be given together with other sympathomimetic agents. β-adrenoceptor blocking agents inhibit the bronchodilator activity of salbutamol. Consequently β-blockers should not be used in asthmatic patients as they may increase airways resistance.
Buventol Easyhaler should be administered cautiously to patients suffering from hyperthyroidism, cardiovascular disease and diabetes.
Potentially serious hypokaliemia may result from β2 agonist therapy mainly from parenteral and nebulised administration. Particular caution is advised in acute severe asthma as this effect may be potentiated by concomitant treatment with xanthine derivatives, steroids, diuretics and hypoxia. It is recommended the serum potassium levels are monitored in such situations.
Pregnancy: Administration of medicines during pregnancy should only be considered if the expected benefit to the mother is greater than any possible risk to the foetus.
During worldwide marketing experience, rare cases of various congenital anomalies, including cleft palate and limb defects have been reported in offspring of patients treated with salbutamol. Some of the mothers were taking multiple medications during their pregnancy. Because no consistent pattern of defects can be discerned, and baseline rate of congenital anomalies is 2-3%, a relationship with salbutamol use cannot be established.
Lactation: It is not known whether salbutamol has a harmful effect on the neonate. As salbutamol is probably excreted in breast milk, its use in nursing mothers is not recommended unless the expected benefits outweigh any potential risk.
Salbutamol may cause fine tremor of skeletal muscle (particularly of the hands), palpitations and muscle cramps. Slight tachycardia, tenseness, headaches and peripheral vasodilation have been reported after large doses.
Hypersensitivity reactions including angioedema, urticaria, bronchospasm, hypotension and collapse have been reported rarely.
Paradoxical bronchospasm may also occur requiring immediate discontinuation of therapy and institution of appropriate treatment.
Salbutamol will enhance the activity of other β2 sympathomimetics. β receptor blocking agents such as propranolol inhibit the activity of salbutamol. The effects of salbutamol may be enhanced by concomitant administration of aminophylline or other xanthines.
Peripheral vasodilation and increased irritability of skeletal muscle are signs of overdose due to β receptor sympathomimetics. Sinus tachycardia develops and is partly attributable to a decrease in peripheral resistance associated with a reflex increase in cardiac output. If overdose occurs salbutamol should be withdrawn and if necessary a cardio-selective β blocker such as metoprolol in a single dose of up to 5mg may be given by injection.
Room temperature. Use of the protective cover for storage of the Easyhaler is recommended once the aluminium foil has been opened.
Prescription Medicine.
100mcg/dose and 200mcg/dose dry powder for inhalation: 200 doses.
Salbutamol is 2-tert-Butylamino-1-(4- hydroxy-3-hydroxy-methylphenyl) ethanol. Its molecular formula is C13H21NO3 and it has a molecular weight of 239.3.
Douglas Pharmaceuticals Ltd
PO Box 45-027
AUCKLAND 8
New Zealand
Ph: (09) 835-0660
Fax: (09) 835-0665
14 April 1999