Conjunctivitis of allergic origin: immunologic mechanisms and current approaches to therapy.

A double-blind cross-over sequential trial of a new antiallergic compound, disodium cromoglycate (' FPL670 ', ' Intal ') was carried out over a period of 6 weeks in ten patients severely disabled with allergic bronchial asthma. There was a significant clinical improvement during administration of FPL670 plus isoprenaline in all patients compared with two periods in which isoprenaline alone was given. Spirometric improvement occurred in only four patients. Subsequent experience over periods up to 26 months with these and other patients has confirmed the therapeutic value and safety of FPL670 in the management of allergic bronchial asthma.

A double-blind trial of disodium cromoglycate in the treatment of allergic bronchial asthma

Evidence questioning cromolyn’s effectiveness and selectivity as a ‘mast cell stabilizer’ in mice

Cromolyn is a white crystalline powder which is poorly absorbed from the gastrointestinal tract. Its therapeutic value lies in its functions as an inhaled or topically applied agent. Cromolyn has been approved in the United States for asthma therapy since 1973. It was marketed at that time as a drug to reduce the corticosteroid requirements of severe asthmatics. It clearly did not live up to that claim. Initial enthusiasm for cromolyn was replaced by disillusionment. In the last few years, investigators have taken another look at cromolyn and have a renewed interest in it. Cromolyn's mechanisms of action remain only partially understood. It appears to block allergic mediator release from certain mast cells. It may also decrease bronchial hyperreactivity. The frequency of drug toxicity at customary dosages is extremely low. Adverse effects tend to be mild, short-lived and without sequelae. Currently, cromolyn is a first line therapy for mild to moderate asthma requiring chronic treatment. It is also of proven efficacy in the treatment of allergic rhinitis, allergic conjunctivitis and vernal keratoconjunctivitis.

Cromolyn sodium: a review.

In order to evaluate drug effects on exercise-induced asthma, and to study associated metabolic and pulmonary effects, a method for inducing a consistent response is needed. A method is presented, consisting of 5 min of treadmill exercise sufficiently strenuous to increase a subject's heart rate to 90% of the predicted maximum for age; the airway response is measured frequently for 20 min after exercise. Using this method, 48 asthmatics and 13 nonasthmatics were evaluated. Although none developed severe asthma, a significant airway response occurred in 71% of asthmatics. The severity of exercise-induced asthma depended on intensity and duration of exercise but not on time of day. The method described allows a consistent stress to be applied to a wide age range, and response to this stress was consistent at various ages. Variation of a subject's response following repeated testing was less than that reported with other methods, and could be further reduced by selecting only those subjects with greater than 20% change in one-second forced expiratory volume (FEV1) and by completing studies in less than a month.

https://www.jacionline.org/article/0091-6749(76)90122-6/pdf

A standardized method of evaluating exercise-induced asthma.

Because of several controversial reports concerning the efficacy of cromolyn sodium in the treatment of asthma, the Drug Committee of the American Academy of Allergy instituted a collaborative study in November, 1969. The protocol was designed to select patients according to age, cooperativeness, severity of asthma, and type of asthma—extrinsic, intrinsic, or mixed. The basic design of the study involved a baseline period of one week in which inert filler (lactose) was administered in the Spinhaler apparatus and during which the patient could be familiarized with the complex record keeping. The basal period was followed by two 4 week crossover periods during which cromolyn sodium was alternated with placebo. Symptom scores, drug intake, physician evaluation, patient preference, and simple pulmonary function tests were subjected to statistical analysis. Results gleaned from 252 completed patients indicated a favorable response for the drug as compared to placebo in patient symptom scoring, ephedrine-like drug scores, physician evaluation, and patient preference. A drug carry-over effect extending over a period of 4 weeks created difficulty in assessing results of the placebo period in patients who received active drug during the first 4 week period. Although a favorable drug effect was usually observed when cromolyn sodium was the first drug in the trial sequence, efficacy was more clear-cut during active drug administration in patients who received placebo during the first 4 weeks of the study. The mechanism of this carry-over effect was not apparent. The amelioration index tended to be higher in the pediatric group and in those patients whose asthma was classified as mixed. No change in the objective indices of one-second forced expiratory volume or peak expiratory flow measured once every 2 weeks was obtained. No serious side effects were noted by the participating investigators. These results indicate that cromolyn sodium will be a useful adjunct to the pharmacological treatment of asthma.

https://www.jacionline.org/article/0091-6749(72)90017-6/pdf

R R Evans

Papers

A controlled study of cromolyn sodium sponsored by the Drug Committee of the American Academy of Allergy