Caffeine as a modulator of bronchial hyper-reactivity in adult asthmatics

ABSTRACT

The effect of caffeine [adenosine antagonist] on methacholine bronchial reactivity, pulmonary ventilation, heart rate, and blood pressure was stupied in adult asthmatics to 1- evaluate the role of adenosine in the pathogenesis of bronchial hyper-reactivity, 2- have idea about the site of action of caffeine as a ventilatory stimulant. 24 asthmatic patients, classified into three comparable groups were studied. Methacholine bronchial reactivity [PD-20-FEV[1]], tidal volume [VT], respiratory rate [R.R],minute ventilation [VE], heart rate [H.R] and mean blood pressure [P] were measured before and two hours after caffeine ingestion [2 mg/kg in the first group, 5 mg/kg in the second, 7 mg/kg in the third]. caffeine in the three doses, has significantly increased the PD-20-FEV[1] in a fashion related to the baseline PD-20-FEV[1] but not related to the induced dronchodilatation. The three doses of caffeine have resulted in significant ventilatiry stimulation, however, the low dose [2 mg/kg] did not has significant effect on RR, HR and P.