Nedocromil sodium inhibits the early and late asthmatic response to exercise.

A double-blind, crossover study was carried out to investigate the effect of nedocromil sodium on the dual asthmatic response to exercise challenge. Nineteen patients with a late response to bicycle exercise were randomly treated on two study days with 4 mg nedocromil sodium or a matched placebo aerosol, 30 min before commencing exercise. Peak flow was measured before exercise, at intervals up to 60 min after exercise, then hourly for up to 13 h. In 12 of the 19 patients an early reaction to exercise occurred. In 8 of these 12 patients the early reaction could be inhibited by nedocromil sodium (p less than 0.01) although in half of these patients placebo was also shown to be protective. In the case of the late reaction after exercise challenge, 4-13 h after exercise challenge, nine patients were clearly protected by pretreatment with nedocromil sodium (p less than 0.01) when the fall in peak expiratory flow rate was related to the pre-exercise baseline, four patients showed an equal protective effect of placebo and nedocromil sodium, whilst the others were not protected. When the late asthmatic response (fall in peak expiratory flow rate) after exercise challenge was related to control diurnal peak flow values, the number of responses was reduced; the protective effect of nedocromil sodium remained.

Real and pseudo late asthmatic reactions after submaximal exercise challenge in patients with bronchial asthma. A new definition for late asthmatic responses after exercise challenge.

The late asthmatic reaction after exercise challenge remains a controversial issue. In this study, 21 patients recorded peak expiratory flow rate (PEFR) on two control days without performing exercise. There was no difference between both control days when PEFR at 1 h was compared with baseline PEFR and when PEFR at 4 to 13 hours was compared with baseline PEFR. After analyzing variation coefficients of baseline PEFR on a control day and exercise day, PEFR was not allowed to differ more than 15.3 percent in the same patient when comparing exercise day and control day for the late fall in PEFR in the study. In 17 of 81 patients, a late asthmatic reaction after exercise challenge was present when PEFR fall was greater than or equal to 20 percent compared with baseline PEFR value. In eight of the 17 patients, a real late asthmatic reaction to exercise challenge was present with a PEFR fall greater than or equal to 20 percent on at least three successive time points and who had a PEFR fall greater than or equal to 20 percent compared with corresponding clocktime on a control day. The late asthmatic reaction to exercise challenge is characterized not as a nonspecific epiphenomenon, but as a fall in PEFR of greater than or equal to 20 percent compared with baseline PEFR value and with corresponding clocktime on a control day on at least three successive time points. Graphic illustration of airway responses following exercises may facilitate the detection of a late asthmatic response.

Immediate and late asthmatic responses induced by exercise in patients with reversible airflow limitation.

The existence and prevalence of late asthmatic responses to exercise in patients is uncertain. We investigated whether the late falls of peak expiratory flow rate (PEFR) after exercise challenge were still significant after comparison with the corresponding clocktime PEFR on a control day. We examined 86 patients with reversible airflow limitation, 79 with asthma and 7 with chronic obstructive pulmonary disease (COPD), all under regular treatment with bronchodilators and/or anti-inflammatory agents. Patients were randomized for a control day and an exercise day and PEFR was recorded hourly. On the exercise day, each patient underwent an 8 minute bicycle ride at 90% of predicted heart-rate. An early and a late asthmatic response to exercise were considered to occur when PEFR decreased by 10% or more on the exercise day compared to the corresponding clocktime PEFR on the control day. Thirty-three patients (38%) had a 10% or greater fall of PEFR at 4 to 13 hours after exercise when PEFR was compared with the corresponding clocktime on a control day. Seven (8%) had an isolated late asthmatic response, and 26 (30%) had a dual asthmatic response. We conclude that true late asthmatic responses develop after exercise in a significant number of patients with well controlled reversible airflow limitation.