Indications

Salbutamol Respirator Solution is indicated for the treatment of severe acute asthma (status asthmaticus) and also forms of bronchospasm.

Therapeutic Class

Short-acting selective & β2-adrenoceptor stimulants

Pharmacology

Salbutamol is a selective beta2-adrenoceptor agonist. At therapeutic doses, it acts on the beta2-adrenoceptors of bronchial smooth muscle, with little or no action on the ß1-adrenoceptors of cardiac muscle. Salbutamol provides short acting (4-6 hours) bronchodilatation with a fast onset (within 5 minutes) in reversible airways obstruction. It also has an anti-inflammatory effect on mast cells causing inhibition of release of bronchoconstrictor mediators including histamine, neutrophil chemotactive factor (NCF) and prostaglandin D2.

Dosage & Administration

By Intermittent Administration:

Adult: salbutamol Respirator Solution 0.5-4.0 ml should be diluted to final volume of 2.0-4.0 ml with normal saline for injection. The resulting solution is inhaled from a suitably driven nebuliser until aerosol generation ceases. Using a correctly matched nebuliser and driving source this should take about 10 minutes.

Salbutamol Respirator Solution may be used undiluted for intermittent administration. For this 2.0 ml of the solution is placed in the nebuliser and the patient allowed to inhale until bronchodilatation is achieved. This usually takes 3-5 minutes. Some adult patients may require higher doses of salbutamol upto 10 mg in which case nebulisation may continue until aerosol generation ceases.

Children under 12 years age: 0.5 ml of the solution diluted to 2-4 ml with normal saline. Some children may however require higher doses of upto 1 ml of the solution. Intermittent treatment may be repeated four times a day.

By Continuous Administration:

Salbutamol Respirator Solution is diluted with normal saline for injection, 1-2 ml solution made upto 100 ml with diluent. The diluted solution is administered as an aerosol by a suitably driven nebuliser. The usual rate of administration is 1 to 2 mg/hour. Delivery of the aerosol may be by face mask or via an endotracheal tube. Intermittent positive pressure may be used but is rarely necessary. When there is risk of anoxia through hypoventilation, oxygen should be added to the inspired air.

Interaction

Salbutamol and non-selective beta-blocking drugs such as propranolol should generally not be prescribed together. Potentially serious hypokalaemia may result from beta2-agonist therapy. Particular caution is advised in acute severe asthma as this effect may be potentiated by concomitant treatment with xanthine derivatives, steroids, diuretics, and by hypoxia. It is recommended that serum potassium levels are monitored in such situations.

Contraindications

History of hypersensitivity to any of its components. Salbutamol presentation should not be used for threatened abortion during the first or second trimester of pregnancy. It should be used with care in patients known to have received large doses of other sympathomimetic drugs.

Side Effects

A small increase in heart rate may occur in patients who inhale large doses of Salbutamol. This is not usually accompanied by any changes in ECG. Other side effects which occur with high doses are peripheral vasodilation and fine tremor of skeletal muscle.

Pregnancy & Lactation

Unnecessary administration of drugs during the first trimester of pregnancy is undesirable.

Precautions & Warnings

It should be used with care in patients suffering from thyrotoxicosis. Salbutamol Respirator Solution should be used with a respirator or nebuliser, only under the direction of a physician. Not to be injected, or taken orally. Patients receiving treatment at home with Salbutamol Respirator Solution should be warned that if either usual relief is diminished or the usual duration of action reduced, they should not increase the dose or its frequency of administration but seek medical advice.

Overdose Effects

During continuous administration any signs of overdosage may be counteracted by withdrawal of the drug. The preferred antidote for overdosage is a cardioselective betablocker, but betablockers should be used with caution in patients with a history of bronchospasm.

Storage Conditions

Store at a cool & dry place, protected from light. Once a bottle has been opened the contents should be discarded after one month.