As terbutaline is excreted mainly via the kidneys, the dose of Bambec should be halved in patients with an impaired renal function (GFR ≤ 50 mL/min). In patients with liver cirrhosis, and probably in patients with other causes of severely impaired liver function, the daily dose must be individualised, taking into account the possibility that the individual patient could have an impaired ability to metabolise bambuterol to terbutaline.
Therefore, from a practical point of view, the direct use of the active metabolite, terbutaline (Bricanyl™), is preferable in these patients. As for all β2-agonists, caution should be observed in patients with thyrotoxicosis. Cardiovascular effects may be seen with sympathomimetic drugs, including Bambec.
There is some evidence from post-marketing data and published literature of rare occurrences of myocardial ischaemia associated with beta agonists. g. ischaemic heart disease, arrhythmia or severe heart failure) who are receiving Bambec 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. Although Bambec is not indicated for the treatment of premature labour it should be noted that bambuterol is metabolised to terbutaline and that terbutaline should not be used as a tocolytic agent in patients with pre- existing ischaemic heart disease or those patients with significant risk factors for ischaemic heart disease.
Due to the hyperglycaemic effects of β2-agonists, additional blood glucose controls are recommended initially in diabetic patients. Due to the positive inotropic effects of β2-agonists these drugs should not be used in patients with hypertrophic cardiomyopathy.
β2-agonists may be arrhythmogenic and this must be considered in the treatment of the individual patient. Unpredictable inter-individual variation in the metabolism of bambuterol to terbutaline has been shown in subjects with liver cirrhosis.
The use of an alternative β2-agonist is recommended in patients with cirrhosis and other forms of severely impaired liver function. Potentially serious hypokalaemia may result from β2-agonist therapy. Particular caution is recommended in acute severe asthma as the associated risk may be augmented by hypoxia.
5). It is recommended that serum potassium levels are monitored in such situations. Asthma patients who require treatment with Bambec must have optimum anti- inflammatory treatment with corticosteroids. The patients must be instructed to continue taking their anti-inflammatory medication after the start of treatment with Bambec, even if the asthma symptoms diminish.
If a previously effective dosage regimen no longer gives the same symptomatic relief this suggests that the underlying disease has worsened. The patient should urgently seek further medical advice and a re-evaluation of the asthma treatment must be carried out.