[Effect of barnidipine hydrochloride on the autonomic nervous system: difference between short- and long-acting components of calcium antagonist].
Short-acting calcium antagonists have a deleterious effect on the prognosis for patients with myocardial ischemia, possibly caused by overactivation of sympathetic nerves due to vasodilatation, negative inotropism, or coronary steal. However, there is considerable debate about whether long-acting calcium antagonists as well as the short-acting calcium antagonists have the same effect. Barnidipine-HCl is a newly-developed calcium antagonist with 1:2 short- and long-acting particles. This study evaluated the changes of autonomic tone due to barnidipine. Both the short- and long-acting effect of the calcium antagonist was evaluated. Eleven patients with primary hypertension underwent 24-hour ambulatory electrocardiogram and blood pressure monitoring before and after the treatment with barnidipine. Heart rate and blood pressure were compared before and after the medication. Heart rate variability was analyzed with a Marquette 8000/T. High frequency power (HF), as a parameter of vagal tone, and the ratio to low frequency power (LF), as a parameter of sympathetic tone, were obtained. Twenty-four-hour average blood pressure decreased significantly during the day, but nocturnal hypotension was not observed. Heart rate did not increase. HF decreased at the peak of the short- and long-acting components. LF/HF increased at the peak of the short-acting component. Short-acting particles of barnidipine had a deleterious effect on the autonomic tone, that is overactivation of sympathetic tone and suppression of vagal tone. Long-acting particles of barnidipine suppressed the vagal tone. These findings suggest that short-acting calcium antagonists may cause arrhythmia or deterioration of coronary ischemia.
Soejima
K
K
Department of Medicine, Keio University School of Medicine, Tokyo.
Akaishi
M
M
Oyamada
K
K
Mitamura
H
H
Ogawa
S
S
D001341:Autonomic Nervous System / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000009:adverse effects / Q000494:pharmacology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology
D002121:Calcium Channel Blockers; C050699:mepirodipine; D009543:Nifedipine