BRONCHOSPASM ON ~-BlOCKERS USED IN ASTHMATICS

Responses to a recent report concerning nadolol Considering in retrospect the report ofa near-fatal case of bronchospasm from the ~-blocker nadolol [see Inpharma 277: 6 (7 Mar 1981 JJ, perhaps a more aggressive approach with salbutamol (albuteroJ) might have been attempted. A ~-agonist should be able to override ~-blockade, but in normal patients a 60-fold increase in salbutamol dose is needed to achieve bronchodilation after 80mg propranolol. This means a dose of I Dmg salbutamol every 10 min by inhalation - heart rate, ECG and BP permitting. Other alternatives worth trying may be ipratropium or atropine, perhaps aminophylline, or even dinoprostone (prostaglandin E1) which should bypass the effects of ~-blockade, though it has not been tried in practice [Tatlersjield. A .E.: British Medical lournal282: 901 (J 4 Mar 1981 JJ. The dangers of ~-blockade in asthma are still not fully appreciated by many. The suggestion that a j3-blocker, in an :lsthmatic, should be started under medical supervision, monitoring peak flow, is wise but may not be enough, since several non-responses do not guarantee that bronchospasm may not occur later under other conditions such as with cold or exercise. Any asthmatic given a ~-blocker should be well versed in aerosol technique and should always carry a ~-agonist bronchodilator inhaler. Even then, bronchoconstriction does not always respond to ~-agonists, perhaps because the bronchospasm is a consequence of some action other than j3-blockade, from which it follows that the cardioselective ~-blockers may be no safer than the non-selective ones. Skinner suggests that a possible alternative to a ~-blocker may be the combined a- and ~-blocker labetalol [Skinner. C:: British Medical lournal282: 901 (14 Mar 1981))./

And the manufacturer (Squibb) comments The report is a timely reminder of the care needed in giving any j3-blocker (cardioselective or otherwise) to any patient with a history of wheezing from any cause. Cardioselectivity is not absolute but relative and dose-dependent, and selectivity can be lost in some, even at normal therapeutic plasma levels. Several studies attest to this. Despite the selectivity of atenolol , for example, the inCidence of frequent or sporadic bronchospasm with this drug varies between 5-10 % whiie, with the non-selective nadolol, an incidence of 2 % (in 10,000 cases) has been reported. In patients with airway obstruction all ~-blockers should be avoided [Jackson. D.: British Medicallou rna I 282: 902 (J 4 Mar 198 I)]. The reaction to nadolol was also referred to in The Pharmaceutical Journal 226: 197 (21 Feb 1981), bringing a similar reply from the manufacturer [Woods. P.: Pharmaceutical lournal226: 290 (21 Mar 1981]..J

2 INPHARMA 28 Mar 1981 0156-2703 / 81 / 0328-0002 $00.50 / 0 © ADIS Press