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Interaction Between Propranolol and Propafenone in Healthy Volunteers
Author(s) -
Kowey Peter Russell,
Kirsten Edward B.,
Fu ChauHwei J.,
Mason William D.
Publication year - 1989
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1989.tb03373.x
Subject(s) - propafenone , propranolol , medicine , blood pressure , heart rate , concomitant , pharmacokinetics , anesthesia , cardiology , atrial fibrillation
The effects of propafenone on the pharmacokinetics and pharmacodynamics of propranolol were evaluated in 12 healthy male subjects. Both propafenone and propranolol were each administered alone for one week followed by concomitant administration for an additional week. Blood samples, obtained at steady‐state, were analyzed for propafenone and its two metabolites as well as for propranolol and 4‐hydroxypropranolol. Left ventricular function, exercise performance and electrocardiographic intervals were assessed. Coadministration of propranolol did not produce any significant change in propafenone kinetics including peak plasma concentration (C max ), time to peak plasma concentration (T max ), elimination rate constant (t 1/2 ), mean steady‐state plasma concentration (C ss ), or area under the concentration vs time curves. However, concomitant propafenone administration significantly increased C max (83%), T max (55%), t 1/2 (30%), and C ss (213%) which were accompanied by significant decreases in plasma levels of 4‐hydroxy‐propranolol. Propafenone and propranolol significantly reduced supine systolic and diastolic blood pressure by 2.5 to 15.4%. The combination did not reduce diastolic blood pressure further (64.0 ± 2.8 to 59.7 ± 1.7 mmHg) nor did it produce a supplemental reduction in heart rate (12% reduction with propranolol, 10% reduction with concomitant administration). Propranolol, but not propafenone, significantly decreased end‐diastolic volume index (13%), stroke volume index (15%), and velocity of circumferential fiber shortening (19%). The combination did not cause any further changes in echocardiography measurements. Electrocardiographic intervals were not altered by either drug used alone or in combination. We conclude that the concomitant administration of propafenone and propranolol can produce marked increases in propranolol plasma levels with only modest enhancement of beta‐adrenergic blocking effects when administered to patients with preserved left ventricular function, and a normal conduction system.