PT  - JOURNAL ARTICLE
AU  - J C Henderson
AU  - F O'Connell
AU  - R W Fuller
TI  - Decrease of histamine induced bronchoconstriction by caffeine in mild asthma.
AID  - 10.1136/thx.48.8.824
DP  - 1993 Aug 01
TA  - Thorax
PG  - 824--826
VI  - 48
IP  - 8
4099  - http://thorax.bmj.com/content/48/8/824.short
4100  - http://thorax.bmj.com/content/48/8/824.full
SO  - Thorax1993 Aug 01; 48
AB  - BACKGROUND--While high doses of caffeine may affect pulmonary function and bronchial challenge tests in patients with mild asthma, the effects of lower doses (< or = 5 mg/kg) are less well documented. Specific recommendations exist for withholding theophylline, but not caffeine, before bronchoprovocation and pulmonary function testing. METHODS--To assess the effect of a single oral dose of caffeine (5 mg/kg) on FEV1 and bronchial responsiveness to histamine a double blind, placebo controlled study was performed in eight patients with mild stable asthma. RESULTS--While caffeine had no effect on FEV1, mean (95% confidence interval) log PC20 histamine was significantly higher 150 minutes [caffeine = 0.99 (0.2) mg/ml, placebo = 0.53 (0.29)] and 240 minutes [caffeine = 0.89 (0.24), placebo = 0.44 (0.26)] after administration of caffeine than after placebo. CONCLUSIONS--Caffeine should be excluded from the diet for a period of more than four hours before bronchial provocation testing. The exact length of time for which it must be excluded requires further study.