As for all beta2-agonists caution should be observed in patients with thyrotoxicosis.
Cardiovascular effects may be seen with sympathomimetic drugs, including Bricanyl. There is some evidence from post-marketing data and published literature of myocardial ischaemia associated with beta agonists.
Due to the positive inotropic effect of the beta2-agonists, these drugs should not be used in patients with hypertrophic cardiomyopathy.
Bronchospasm
Patients with underlying severe heart disease (e.g. ischaemic heart disease, arrhythmia or severe heart failure) who are receiving Bricanyl should be warned to seek medical advice if they experience chest pain or other symptoms of worsening heart disease.
Attention should be paid to assessment of symptoms such as dyspnoea and chest pain, as they may be of either respiratory or cardiac origin.
Due to the hyperglycaemic effects of beta2-agonists, additional blood glucose controls are recommended initially in diabetic patients.
Potentially serious hypokalaemia may result from beta2-agonist therapy. Particular caution is recommended in acute severe asthma as the associated risk may be augmented by hypoxia. The hypokalaemic effect may be potentiated by concomitant treatments (see section 4.5). It is recommended that serum potassium levels are monitored in such situations.
If a previously effective dosage regimen no longer gives the same symptomatic relief, the patient should urgently seek further medical advice. Consideration should be given to the requirements for additional therapy (including increased dosages of anti-inflammatory medication). Severe exacerbations of asthma should be treated as an emergency in the usual manner.
Lactic acidosis has been reported in association with high therapeutic doses of parenteral and nebulised short-acting beta-agonist therapy, mainly in patients being treated for an acute asthma exacerbation (see section 4.8). In patients not adequately responding to acute Bricanyl therapy, consideration should be given to the presence of lactic acidosis as a possible contributing factor to ongoing respiratory symptoms.
Tocolysis
Any decision to initiate therapy with Bricanyl 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.
Bricanyl 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- during treatment of preterm labour, when high doses of Bricanyl are used, diabetic mothers may develop hyperglycaemia and lactacidosis. In these patients glucose and acid-base balance should be carefully monitored.
• Potassium levels– beta-agonists are associated with a decrease in serum potassium which increases the risk of arrhythmias (see section 4.5).
Treatment should be discontinued if signs of myocardial ischaemia (such as chest pain or ECG changes) develop.
Bricanyl 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 section 4.3). 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 Bricanyl.
An increased tendency to bleeding has been described in connection with cesarean section (give propranolol 1-2 mg i.v.) in patients treated with Bricanyl solution for injection for preterm labour.
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 section 4.2 and 4.8).
Blood pressure and heart rate
Increases in maternal heart rate of the order of 20 to 50 beats per minute usually accompany 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 being greater on diastolic than on systolic pressure. Falls in diastolic pressure are usually within the range of 10 to 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 minimise the risk of hypotension associated with tocolytic therapy, special care should be taken to avoid caval compression by keeping 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 section 4.5).
Hyperthyroidism
Bricanyl should only be administered cautiously to patients suffering from thyrotoxicosis after careful evaluation of the benefits and risks of treatment.
Sodium content
This medicinal product contains less than 1 mmol sodium (23 mg) per ampoule, that is to say essentially 'sodium-free'.