Mutual inhibition and synergistic effects of ergotamine and the calcium antagonist darodipine.
The interaction between ergotamine 3 and 30 micrograms/kg i.v. and darodipine (PY108-068) 30 micrograms/kg i.v. was studied in anaesthetized cats. Ergotamine decreased heart rate, cardiac output and total peripheral conductance dose-dependently. Ergotamine caused regional vasoconstriction (measured with tracer microspheres) in the heart, kidneys, adrenals, liver, spleen, skin and arterio-venous shunts but dilatation in the pancreas and skeletal muscle, possibly attributable to serotoninergic stimulation. Darodipine reversed most ergotamine effects except those on the spleen, skin and arterio-venous shunts. Since constriction of arterio-venous shunts was not inhibited, ergotamine is unlikely to lose its effectiveness in migraine patients under concomitant dihydropyridine treatment, while unwanted vasoconstrictor effects are likely to be diminished.
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002415:Cats; D004357:Drug Synergism; D004878:Ergotamine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects*; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009928:Organ Specificity; D012039:Regional Blood Flow / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects
D002121:Calcium Channel Blockers; D009543:Nifedipine; C034600:darodipine; D004878:Ergotamine