ERYTHROCYTE AND PLATELET CATIONIC CONCENTRATIONS AND TRANSPORT-SYSTEMS IN NORMAL VOLUNTEERS TREATED WITH CARMOXIROLE

The effect of carmoxirole, a presynaptic dopamine (DA2) receptor agoni st, on blood pressure, plasma catecholamines, renin-aldosterone and at rial natriuretic peptide and the intracellular concentration and trans membrane fluxes of Na+ and K+, in erythrocytes and platelets was studi ed in 24 normal men, using a double-blind, parallel study design. Afte r a run-in period of 1 week, the subjects were treated with either pla cebo (n = 8) or 0.5 mg carmoxirole (n = 16) once daily for 1 week. Blo od pressure and heart rate were not changed during carmoxirole adminis tration in these normal men. Surprisingly, no significant effect of ca rmoxirole was found on the circulating plasma concentration of noradre naline, adrenaline or dopamine. Other hormones such as renin, aldoster one and atrial natriuretic peptide were also not changed during carmox irole administration. No significant effect of carmoxirole could be de monstrated on the intracellular concentration of Na+, K+, Mg2+ and Ca2 + and on the transmembrane fluxes of Na+ and K+ in erythrocytes and pl atelets. In the carmoxirole-treated subjects (n = 16), 6 subjects repo rted spontaneously adverse events such as syncope, dizziness and vomit ing tendencies and/or fatigue.