Single-dose slow-release aminophylline at night prevents nocturnal asthma

ACTH 1-17 effects in intrinsic bronchial asthma

We have studied the effect of Synchrodyn 1-17 (100 micrograms/day/15 days, intramuscularly) on 12 patients with intrinsic asthma, presenting a circadian pattern in several functional parameters related to the bronchial patency (and/or with bouts of nocturnal asthma). Treatment with ACTH 1-17 had two main effects: the pathological rhythms of the bronchial tone disappeared and there was a clear general improvement in the indices of bronchial patency. The drug was well tolerated. Euphoria and water retention were the side effects: they were noticed in a variable number of subjects and disappeared after discontinuation of treatment.

Twice daily slow-release theophylline vs placebo for 'morning-dipping' in asthma

We report the results of a double-blind control crossover trial of slow release theophylline Nuelin S.A. in improving symptoms of 'morning-dipping' in twelve asthmatic patients. Sleep disturbance was lessened and 'morning-dipping', though not abolished, was improved by 24% (P less than 0.01). Mean peak expiratory flow-rate (PEFR) on waking was significantly higher on active drug (262 l/min vs 226 l/min, P less than 0.001) as were the evening PEFRs (316 l/min vs 285 l/min, P less than 0.05). Seven of the 12 patients achieved 26% improvement in mean PEFR (P less than 0.05) with plasma theophylline levels in the range 28-44 mumol/l. The other five patients improved by 9% (P less than 0.02) with levels in the range 55-66 mumol/l. Mean plasma cyclic AMP 4-6 h after theophylline was significantly higher than with placebo (27.0 nmol/l vs 17.6 nmol/l, P less than 0.05) but significant correlations between cyclic AMP and theophylline levels, and cyclic AMP and PEFR were not demonstrated. A total of nine patients, 33% of those originally recruited for this study, withdrew prior to the double-blind phase because of unacceptable side-effects of theophylline, namely nausea and headache.

Ketotifen and nocturnal asthma

Patients with asthma often wheeze at night and they also become hypoxic during sleep. To determine whether ketotifen, a drug with sedative properties, is safe for use at night in patients with asthma, we performed a double blind crossover study comparing the effects of a single 1 mg dose of ketotifen and of placebo on arterial oxygen saturation (SaO2), breathing patterns, electroencephalographic (EEG) sleep stage, and overnight change in FEV1 in 10 patients with stable asthma. After taking ketotifen, the patients slept longer and their sleep was less disturbed than after taking placebo, true sleep occupying 387 (SEM 8) minutes after ketotifen and 336 (19) minutes after placebo (p less than 0.02). On ketotifen nights the patients had less wakefulness and drowsiness (EEG sleep stages 0 and 1) and more non-rapid eye movement (non-REM) sleep than on placebo nights, but the duration of REM sleep was similar on the two occasions. Nocturnal changes in SaO2, the duration of irregular breathing, and overnight change in FEV1 were unaffected by ketotifen.

Investigation of diurnal changes in the disposition of theophylline

The mechanism of observed temporal variations in plasma theophylline concentrations has been investigated. Eight healthy volunteers were given both oral and intravenous doses of theophylline (5 mg/kg) at 09.00 h and 21.00 h under controlled conditions. Regular plasma concentration measurements were made following each dose in order to determine the diurnal and nocturnal disposition of the drug. Plasma theophylline concentrations at 0.5 h following each oral dose were 6.9 +/- 0.8 micrograms/ml, a.m., and 3.9 +/- 0.6 microgram/ml, p.m. (P less than 0.05). Time to peak concentration was 1.69 +/- 0.28 h, a.m.; 2.13 +/- 0.23 h, p.m. (P less than 0.05). Values for ka were not significantly different, however. Overall bioavailability, volume of distribution and systemic clearances, calculated for the 12 h period after each dose, did not differ significantly between day and night. Diurnal variations in theophylline disposition do not appear to be the result of changes in metabolism or excretion, but may reflect minor differences in absorption.

Theophylline prescribing, serum concentrations, and toxicity

Slow-release theophylline preparations have been prescribed increasingly at the Brompton Hospital, and a serum theophylline assay is requested about once for every ten prescriptions. In a period of eighteen months 1913 such assays were performed, and their influence on management was assessed by retrospective analysis in two groups--113 outpatients on stable dosage with no recent exacerbations of disease; and 28 inpatients and outpatients with concentrations exceeding 25 mg/l. In those with stable treatment, there was only a loose relation between dose and serum theophylline level. High serum levels were associated with abnormal liver function, diuretic use, and duplicate prescribing. When serum theophylline levels were reported high, dosage was always reduced, whereas a low serum theophylline prompted dosage increase in only one-third of patients. Of the patients with very high serum theophylline concentrations (over 25 mg/l), 18 had been receiving oral theophylline and 10 aminophylline by infusion. 3 had seizures, of whom 2 died, and 1 patient was resuscitated after cardiac arrest. Unsuspected theophylline toxicity may be responsible for considerable hidden morbidity.