Low-dose transdermal scopolamine decreases blood pressure in mild essential hypertension

J Hypertens. 1998 Mar;16(3):321-9. doi: 10.1097/00004872-199816030-00009.

Abstract

Background: Increasing cardiovascular parasympathetic nervous activity could have antihypertensive effects. Low-dose transdermal scopolamine increases vagal-cardiac modulation of sinus node and baroreflex sensitivity in healthy subjects and in cardiac patients.

Objective: To study the short-term effects of transdermal scopolamine on blood pressure and cardiovascular autonomic control in patients with mild essential hypertension.

Design: A randomized, double-blind, placebo-controlled crossover trial with 12 untreated middle-aged [aged 39+/-5 years (mean+/-SD)] patients with mild essential hypertension.

Methods: We recorded the electrocardiogram, auscultatory sphygmomanometric and continuous photoplethysmographic finger arterial pressure, and spirometry signals with patients supine and 70 degrees tilted during controlled (0.25 Hz) breathing. Cardiovascular autonomic regulation was analyzed with power spectrum analysis of R-R interval and arterial pressure variability and a spontaneous sequence method for baroreflex sensitivity. In addition, a deep-breathing test was performed to assess maximal breathing-related sinus arrhythmia.

Results: Transdermal scopolamine treatment significantly decreased blood pressure both when patients lay supine and when they were in the 70 degrees tilted position. Scopolamine also slowed heart rate and increased baroreflex sensitivity and R-R interval high-frequency variability for both body positionings. In addition, scopolamine accentuated respiratory sinus arrhythmia during deep breathing and blunted the tilt-induced increase in heart rate. Scopolamine did not affect blood pressure variability.

Conclusions: Transdermal scopolamine decreases arterial pressure, increases baroreflex sensitivity and accentuates vagal-cardiac modulation of sinus node in patients with mild hypertension. Our study supports the hypothesis that increasing cardiovascular parasympathetic activity could have antihypertensive effects in essential hypertension.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Cutaneous
  • Adult
  • Baroreflex / drug effects
  • Baroreflex / physiology
  • Blood Pressure / drug effects*
  • Blood Pressure / physiology
  • Cross-Over Studies
  • Double-Blind Method
  • Female
  • Heart Rate / drug effects
  • Heart Rate / physiology
  • Humans
  • Hypertension / drug therapy*
  • Hypertension / physiopathology*
  • Male
  • Middle Aged
  • Parasympathetic Nervous System / drug effects
  • Parasympathetic Nervous System / physiopathology
  • Parasympatholytics / administration & dosage*
  • Parasympatholytics / adverse effects
  • Parasympatholytics / blood
  • Scopolamine / administration & dosage*
  • Scopolamine / adverse effects
  • Scopolamine / blood
  • Sinoatrial Node / drug effects
  • Sinoatrial Node / physiopathology
  • Tidal Volume / drug effects
  • Vagus Nerve / drug effects
  • Vagus Nerve / physiopathology

Substances

  • Parasympatholytics
  • Scopolamine