Formoterol in clinical practice - safety issues

While short-acting beta (2)-agonists are seen as the cornerstone of treatme nt as relief medication for asthma, current guidelines recommend long-actin g beta (2)-agonists as maintenance therapy in combination with inhaled cort icosteroids in patients with moderate to severe asthma, poorly controlled o n present treatment. Although evidence has shown that formoterol, with its fast- and long-acting profile, is effective when used both as regular and a s-needed therapy in all types of asthma, there has been some concern about the potential of beta (2)-agonists with long-acting profiles to produce sid e effects with a longer duration than seen with short-acting beta (2)-agoni sts. Also, where formoterol is used as needed, a higher total daily dose wo uld be anticipated than when taken twice daily for regular maintenance ther apy and this again has led to some concern. In a number of studies, formote rol has been shown to be well tolerated, and although systemic effects expe cted with this class of drugs did occur, formoterol had significantly less effect on serum potassium, pulse, blood pressure, cardiac frequency and QT interval compared with terbutaline. In addition. the duration of effects wa s equivalent to that observed with terbutaline and salbutamol and the relat ive therapeutic index of formoterol compared with salbutamol was found to b e 2.5. Furthermore, studies looking at long-term use of formoterol have sho wn there is no reduction in bronchodilatory effect. and thus, no developmen t of tolerance. In conclusion, formoterol is well tolerated in high doses, producing side effects typical of its class, but with a duration no longer than occurs with short-acting beta2-agonists. These observations, and the l ack of tolerance development, suggest that formoterol may be appropriate tr eatment for patients with asthma of all types and severities on an as-neede d basis or as regular treatment, (C) 2001 Harcourt Publishers Ltd.