The effect of inhaled RS 7540, a xanthone, on exercise-induced asthma.

The effect of 71 oxo-7-thiomethoxyxanthone-2-carboxylic acid sodium salt (RS 7540) in inhibiting exercise-induced asthma was compared with that of placebo in a double-blind crossover study. Single doses of 40 mg were given by inhalation to 12 patients. Ten of these subsequently received a dose of 20 mg. RS 7540 at both dose levels had a statistically significant effect in giving total or partial protection from exercise-induced bronchospasm; however, no dose relationship was apparent.

Changes in arterial oxygen saturation in patients with hyperreactive airways during a histamine inhalation test.

The arterial oxygen saturation (SaO2) of 55 adult patients with hyperreactive airways was monitored with an eight-wavelength ear oximeter during a histamine inhalation test. The post-challenge fall (mean +/- s.d.) in peak expiratory flow was 38 +/- 15% of the baseline value; it was accompanied by a fall in SaO2 of 1.1 +/- 1.8 per cent, from 96.6 +/- 1.8 to 95.5 +/- 2.3%. It is concluded that, in the histamine inhalation test used in this study, even the development of marked bronchoconstriction usually causes only slight changes in SaO2.

Nitrofurantoin-induced acute, subacute and chronic pulmonary reactions.

The clinical histories of 81 patients with hypersensitivity reactions to nitrofurantoin, 66 of whom had pulmonary reactions, were studied. Of all patients, 94% were women and of these, 43% were between 40 and 59 years of age. The nitrofurantoin preparation that contained vitamin c caused significantly fewer hypersensitivity reactions than the others. Acute pulmonary reactions appeared a mean of 8.7 days after the start of nitrofurantoin treatment. Typical for these were high fever, dyspnoea, cough, blood eosinophilia, bilateral pneumonic or pleuro-pneumonic infiltrations, a reduced transfer factor of the lung and, as revealed in pulmonary biopsy specimens, vasculitis, interstitial inflammation and alveolar exudation. Symptoms of subacute and chronic pulmonary reactions developed after at least 1 and 6 months of treatment, respectively. Findings of interest were anti-nuclear antibodies in serum, capillary sclerosis, interstitial fibrosis and inflammation in pulmonary tissue. Most patients with an acute pulmonary reaction recovered within 15 days, but in more than half of those with chronic reactions slight signs of pulmonary fibrosis persisted on follow-up. The findings suggest that the interstitial pulmonary changes caused by nitrofurantoin are largely the result of an Arthus-type immune complex-mediated reaction.

Exercise-induced asthma and doxantrazole.

In a double-blind cross-over trial in 13 patients with exercise-induced asthma, doxantrazole 200 mg taken orally 1 hour before a standardized exercise test involving stair climbing failed to block post-exercise bronchoconstriction. In an open assessment study with the same patients, increasing the doxantrazole dose to 400 mg did not affect post-exercise bronchoconstriction.

Hypersensitivity to acetylsalicylic acid (ASA) and tartrazine in patients with asthma.

One-hundred and forty asthmatics were tested perorally with acetylsalicylic acid (ASA), and/or with the azo-colour tartrazine; a fall in PEF of more than 20% was accepted as a positive result. About one quarter of the patients displayed a positive reaction to one of the two tested agents. No significant correlation was found between the reactions of these, and the presence of atopy, nasal polyposis, sinusitis, rhinitis, sensitivity to cold air, the age at onset, duration of asthma, or history of sensitivity to alcoholic drinks. The history suggested sensitivity to ingested, possibly coloured, food and drink, in only about one third of the tartrazine-positive cases. The ASA provocation tests were mainly applied to patients with doubtful or negative histories of sensitivity to ASA-containing drugs. The frequency of cross-reactivity between the two tested agents was statistically significant; patients reacting to tartrazine were for the most part, also sensitive to ASA. Tests for sensitivity to analgesics and food additives should be conducted as a routine measure in asthmatics, and sensitive patients should be given information on suitable medication and dietary control.

Double-blind cross-over comparison of clenbuterol and salbutamol tablets in asthmatic out-patients.

A double-blind cross-over comparison of a new beta2-sympathomimetic bronchodilator, clenbuterol, with salbutamol and placebo has been made during a 24 day period of out-patient treatment of 19 adults with moderately severe asthma. Oral clenbuterol (10 mug 3 times a day) and salbutamol (4 mg 3 times a day) were equally and significantly (p less than 0.001) more effective than placebo, when daily records of peak expiratory flow or use of isoprenaline inhalations were the criteria of activity. Daily records of symptoms according to a questionnaire also suggested relief of the subjective effects of asthma during treatment with both active drugs (p less than 0.01).