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Effects of caffeine on baroreflex activity in humans
Author(s) -
MosquedaGarcia Rogelio,
Tseng ChingJung,
Biaggioni Italo,
Robertson Rose M,
Robertson David
Publication year - 1990
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1990.193
Subject(s) - caffeine , baroreflex , heart rate , phenylephrine , placebo , hemodynamics , blood pressure , anesthesia , medicine , alternative medicine , pathology
The effects of caffeine or placebo on blood pressure, heart rate, and baroreflex activation (elicited by phenylephrine) were studied on young normotensive volunteers after a 7‐day caffeine‐free period. Subjects received oral doses of either 250 mg caffeine ( n = 6) or placebo ( n = 4), and hemodynamic changes were studied at 0, 30, 60, 120, and 180 minutes after drug administration. Thirty minutes after the caffeine dose, blood pressure had risen from 127 ± 8/57 ± 4 mm Hg to 136 ± 3/68 ± 5 mm Hg, heart rate was unchanged, and the baroreflex slope had decreased from 31 ± 7 msec/mm Hg to 11.6 ± 2 msec/mm Hg. Baroreflex sensitivity remained inhibited for the rest of the single‐dose experimental period. In contrast, no significant changes were observed after either long‐term caffeine ingestion in the same group or in the placebo group during the single‐ or multiple‐dose study. These findings indicate that single but not multiple caffeine administration inhibits baroreflex activation in normotensive volunteers and this could contribute to the acute hemodynamic effects of caffeine. Clinical Pharmacology and Therapeutics (1990) 48, 568–574; doi: 10.1038/clpt.1990.193