Caffeine abstinence augments the systolic blood pressure response to adenosine in humans.

Blood pressure and heart rate responses to adenosine infusion (35, 70, and 140 microg/kg/min, intravenously) were studied in 7 healthy men after 6, 30, 78, 150, and 318 hours of abstinence from regular caffeine use. The finding that caffeine abstinence augmented the systolic pressor response (from -1 +/- 2 mm Hg at 6 hours to +9 +/- 2 mm Hg at 318 hours; p = 0.01) but not the tachycardic response to adenosine has implications for current clinical and research applications of this purine.