Lack of desensitization of alpha- and beta-adrenoceptor function during chronic treatment of healthy volunteers with ibopamine, an orally active dopamine receptor agonist.
In 18 healthy volunteers, in a double-blind placebo-controlled study, we investigated of whether 14 days treatment with a therapeutic dose of ibopamine (3 x 100 mg/day p.o.), respectively its active metabolite epinine, would desensitize lymphocyte beta 2- or platelet alpha 2-adrenoceptors, or alpha 1- and beta-adrenoceptor mediated (phenylephrine- and isoprenaline infusions, respectively), changes in systolic and diastolic blood pressure and heart rate. Ibopamine-treatment, which resulted in peak plasma epinine concentrations of 4-5 nmol.l-1, neither affected resting heart rate or blood pressure, nor any of the alpha- or beta-adrenoceptor parameters measured. Since in man in general long-term administration of alpha- and beta-adrenoceptor agonists desensitizes alpha- and beta-adrenoceptors, the lack of any alpha- and beta-adrenoceptor desensitizing effect of ibopamine suggests that, in the dose employed (3 x 100 mg per day), ibopamine does not exert alpha- or beta-adrenoceptor agonistic effect in humans.
Brodde
O E
OE
Department of Internal Medicine, University of Essen, Germany.
Klusmann
I
I
Wojcik
M
M
Man in't Veld
A J
AJ
Boomsma
F
F
Michel
M C
MC
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D003846:Deoxyepinephrine / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology*
D015259:Dopamine Agents; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D010656:Phenylephrine; C023487:ibopamine; D007545:Isoproterenol; D003846:Deoxyepinephrine