The management of asthma should normally follow a stepwise programme, and the patient response should be monitored clinically and by lung function tests.
Increasing use of short-acting bronchodilators, in particular beta-2 agonists to relieve symptoms indicates deterioration of asthma control. Under these conditions, the patient's therapy plan should be re-assessed.
Sudden and progressive deterioration in asthma control is potentially life-threatening and consideration should be given to starting or increasing corticosteroid therapy. In patients considered at risk, daily peak flow monitoring may be instituted.
VENTOLIN should be administered cautiously to patients with thyrotoxicosis.
Potentially serious hypokalaemia may result from beta-2 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 by hypoxia. It is recommended that serum potassium levels should be monitored in such situations.
As with other inhalation therapy, paradoxical bronchospasms may occur, resulting in an immediate increase in wheezing after dosing. This should be treated immediately with an alternative presentation or a different fast-acting inhaled bronchodilator, if immediately available. VENTOLIN should be discontinued immediately, and if necessary a different fast-acting bronchodilator instituted for ongoing use.
Nebules: VENTOLIN Nebules must only be used by inhalation, to be breathed in through the mouth, and must not be injected or swallowed.
Patients receiving treatment at home with VENTOLIN Nebules must be warned that if either the usual relief is diminished or the usual duration of action reduced, they should not increase the dose or its frequency of administration, but should seek medical advice.
VENTOLIN Nebules should be used with caution in patients known to have received large doses of other sympathomimetic drugs.
A small number of cases of acute angle closure glaucoma have been reported in patients treated with a combination of nebulised salbutamol and ipratropium bromide. A combination of nebulised salbutamol with nebulised anticholinergics should therefore be used cautiously. Patients should receive adequate instruction in correct administration and be warned not to let the solution or mist enter the eye.
Nebules/Solution for Intravenous Infusion: In common with other beta-adrenoceptor agonists, VENTOLIN can induce reversible metabolic changes such as reversible hypokalaemia and increased blood glucose levels.
The diabetic patient may be unable to compensate for this and the development of ketoacidosis has been reported. Concurrent administration of corticosteroids can exaggerate this effect.
Diabetic patients and those concurrently receiving corticosteroids should be monitored frequently during intravenous infusion of VENTOLIN so that remedial steps (e.g. an increase in insulin dosage) can be taken to counter any metabolic change occurring. For these patients, VENTOLIN Solution for Intravenous Infusion should be diluted with Sodium Chloride Injection BP, rather than Sodium Chloride and Dextrose Injection BP.
Lactic acidosis has been reported very rarely in association with high therapeutic doses of intravenous and nebulised short-acting beta-agonist therapy, mainly in patients being treated for an asthma exacerbation (see Adverse Reactions). Increase in lactate levels may lead to dyspnoea and compensatory hyperventilation, which could be misinterpreted as sign of asthma treatment failure and lead to inappropriate intensification of short-acting beta-agonist treatment. It is therefore recommended that patients are monitored for the development of elevated serum lactate and consequent metabolic acidosis in this setting.
Accuhaler/Inhaler: The dosage or frequency of administration should only be increased on medical advice. In the event of a previously effective dose of inhaled VENTOLIN failing to give relief for at least three hours, the patient should be advised to seek medical advice in order that any necessary additional steps may be taken.
Solution for Intravenous Infusion: The use of salbutamol parenteral preparations in the treatment of severe bronchospasm or status asthmaticus does not obviate the requirement for glucocorticoid steroid therapy as appropriate.
When practicable, administration of oxygen concurrently with parenteral salbutamol is recommended, particularly when it is given by intravenous infusion to hypoxic patients.
Tocolysis: Any decision to initiate therapy with VENTOLIN Solution for Intravenous Infusion should be undertaken after careful consideration of the risks and benefits of treatment.
Treatment should only be carried out in facilities adequately equipped to perform continuous monitoring of maternal and foetal health status. Tocolysis with beta-agonists is not recommended when membranes have ruptured or the cervix dilation is beyond 4 cm.
VENTOLIN Solution for Intravenous Infusion should be used with caution in tocolysis and supervision of cardiorespiratory function and ECG monitoring, should be performed throughout treatment. The following monitoring measures must be constantly applied to the mother and, when feasible / appropriate, to the foetus: Blood pressure and heart rate; ECG; Electrolyte and fluid balance - to monitor for pulmonary oedema; Glucose and lactate levels - with particular regard to diabetic patients; Potassium levels - beta-agonists are associated with a disease in serum potassium which increases the risk of arrhythmias (see Interactions).
Treatment should be discontinued if signs of myocardial ischaemia (such as chest pain or ECG changes) develop.
VENTOLIN Solution for Intravenous Infusion should not be used as a tocolytic agent in patients with significant risk factors for, or a suspicion of any kind of pre-existing heart disease (e.g. tachyarrhythmias, heart failure or valvular heart disease; see Contraindications). In premature labour in a patient with known or suspected cardiac disease, a physician experienced in cardiology should assess the suitability of treatment before intravenous infusion with VENTOLIN Solution for Intravenous Infusion.
Pulmonary Oedema: As maternal pulmonary oedema and myocardial ischaemia have been reported during or following treatment of premature labour with beta-agonists, careful attention should be given to fluid balance and cardio-respiratory function. Patients with predisposing factors including multiple pregnancies, fluid overload, maternal infection and pre-eclampsia may have an increased risk of developing pulmonary oedema. Administration with a syringe pump as opposed to i.v. infusion will limit risk of fluid overload. If signs of pulmonary oedema or myocardial ischaemia develop, discontinuation of treatment should be considered (see Dosage & Administration and Adverse Reactions).
Blood pressure and heart rate: Increases in maternal heart rate of the order of 20-50 beats per minute usually accompany the infusion of beta-agonists. The maternal pulse rate should be monitored and the need to control such increases by dose reduction or drug withdrawal should be evaluated on a case by case basis.
Generally maternal pulse rate should not be allowed to exceed a steady rate of 120 beats per minute.
Maternal blood pressure may fall slightly during the infusion, the effect of being greater on diastolic than on systolic pressure. Falls in diastolic pressure are usually within the range of 10-20 mmHg.
The effect of infusion on foetal heart rate is less marked, but increases of up to 20 beats per minute may occur.
In order to minimize the risk of hypotension associated with tocolytic therapy, special care should be taken to avoid caval compression by keep the patient in the left or right lateral positions throughout the infusion.
Diabetes: Administration of beta agonists is associated with a rise of blood glucose. Therefore blood glucose and lactate levels should be monitored in mothers with diabetes and diabetic treatment adjusted accordingly to meet the needs of the diabetic mother during tocolysis (see Interactions).
Hyperthyroidism: VENTOLIN Solution for Intravenous Infusion should only be administered cautiously to patients suffering from thyrotoxicosis after careful evaluation of the benefits and risks of treatment.
Effects on the Ability to Drive and Operate Machinery: Nebules: None reported.