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Studies on the bronchodilator, tremorogenic, cardiovascular and hypokalaemic effects of fenoterol dry powder in asthma
Author(s) -
BAUER K. G.,
KAIK B.,
SERTL K.,
KAIK G. A.
Publication year - 1993
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.1993.tb00366.x
Subject(s) - fenoterol , bronchodilator , crossover study , medicine , dry powder inhaler , metered dose inhaler , pharmacokinetics , bronchodilatation , asthma , cumulative dose , anesthesia , chemistry , pharmacology , inhaler , alternative medicine , pathology , placebo
1 The airway and tremor response and cardiovascular and hypokalaemic effects of single and cumulative doses of fenoterol given by dry powder capsules (DPC) and by metered dose inhaler (MDI) were studied in asthmatics in two randomized, crossover trials. 2 Single doses of fenoterol DPC and MDI (0.2 mg, 0.4 mg), investigated in 24 subjects, produced similar, dose‐dependent increases in FEV 1 . Fenoterol DPC caused less tremor response and less hypokalaemic effects than fenoterol MDI. 3 Cumulative doses of fenoterol DPC and MDI (0.2, 0.6, 1.4, 3.0, 6.2 mg), investigated in 12 subjects, produced a comparable bronchodilatation (mean maximum increase in FEV 1 was 0.53 ± 0.06/0.52 ± 0.08 1 for DPC/MDI) and a similar, dose‐dependent rise in heart rate (35 ± 3.81/41 ± 2.25 beats min −1 ). The rise in tremor and the fall in plasma potassium were smaller after DPC than after MDI. The mean maximum changes were 51.58 ± 6.41/95.83 ± 6.75 cm s −2 for tremor and −0.68 ± 0.09/−0.96 ± 0.10 mmol 1 −1 for potassium. 4 Our findings may result from a difference in the pharmacokinetics of the dry powder and the aerosol formulation, particularly differences in distribution and absorption. 5 In conclusion, fenoterol DPC used in low therapeutic doses (0.2, 0.4 mg), is preferable to the MDI. Fenoterol DPC used as rescue medication in high cumulative doses, do not suggest a greater safety margin than the MDI and the same restrictions should be considered for the fenoterol dry powder formulation as suggested for the MDI.