INFLUENCE OF TREATMENT WITH BECLOMETHASONE, CROMOGLYCATE AND THEOPHYLLINE ON PERCEPTION OF BRONCHOCONSTRICTION IN PATIENTS WITH BRONCHIAL-ASTHMA

1. Perception of asthma by patients can be assessed from the relations hip between symptom scores and peak expiratory flows, This study was d esigned to investigate the possibility that medication can affect perc eption of the sensation of asthma independently of changes in lung fun ction. 2. Twelve subjects whose asthma was inadequately controlled by inhaled bronchodilator alone were studied during four different drug t reatments over 3 months, Subjective self-assessment of asthma was scor ed on a 10 cm visual analogue scale and followed by three consecutive measurements of peak expiratory flow, using a coded electronic peak fl ow meter, This was recorded not less than three times daily on diary c ards, Observations were recorded during the second week of each of fou r treatments: (i) a run-in period using only inhaled salbutamol as req uired, (ii) inhaled beclomethasone, (iii) inhaled cromoglycate and (iv ) oral theophylline at a dose adjusted to achieve blood levels of 10-2 0 mg/l, Inhaled salbutamol was permitted during the other treatments a s required, Changes in the slope and position of the regression lines of asthma scores on PEF were used to measure changes in perception of asthma on each treatment, Dynamic lung volumes were measured in the cl inic before the study and after each treatment period. 3. In the group as a whole, theophylline improved lung function (mean peak flow and d ynamic lung volumes) without affecting mean visual analogue scores, be clomethasone improved mean visual analogue scores with much less effec t on lung function, while cromoglycate had a small though consistent e ffect on both. 4. Perception of asthma, measured by the relationship b etween peak flow rate and visual analogue scores, was unaffected by cr omoglycate, On theophylline, perception of asthma was heightened in fi ve subjects despite a definite improvement in their peak flow, On becl omethasone, perception of asthma was reduced in most subjects, often w ith no discernible improvement in mean peak flow or dynamic spirometry . 5. Perception of bronchoconstriction in asthma can be affected by dr ugs independently of control of the condition, Theophylline may produc e a paradoxical increase in awareness of asthma in some individuals, W ith beclomethasone therapy a reduction in symptoms of asthma may occur without any improvement in tests of air flow.