Possible Interaction: Dextroamphetamine and Phenoxybenzamine

“Inspection of effects on individual doses of dexamphetamine showed that both phenoxybenzamine and phentolamine could potentiate the effectiveness of low doses of dexamphetamine.”

“ Phenoxybenzamine , phentolamine and prazosin, which all block alpha-adrenergic receptors potentiated the inhibitory effect of D-amphetamine on lordosis behavior.”

“This suggestion is further supported by the demonstration that while D-amphetamine induced H-S is blocked by phenoxybenzamine , other stereotyped motor patterns continue unimpaired.”

“The stimulation produced in dexamphetamine-(but not in vehicle-) treated mice by dexamphetamine was partially blocked by phentolamine, phenoxybenzamine , and propranolol.”

“In other experiments, administration of either the dopamine antagonist pimozide or the α-adrenergic antagonist phenoxybenzamine exacerbated FEAD and also prevented the suppression of FEAD by d-amphetamine.”

“Pimozide and phenoxybenzamine each virtually abolished locomotor stimulation after dexamphetamine , while FLA63 caused significant reduction.”

“The difference in stimulation produced by dexamphetamine in the two groups was completely blocked by phenoxybenzamine (2.5 mg/kg), phentolamine (10 mg/kg), which drugs did not, however, block the locomotor stimulation produced by dexamphetamine in vehicle-treated animals.”

“Adrenergic α1 antagonists prazosin and WB4101 and the nonselective α antagonist phenoxybenzamine completely blocked increase in bursting induced by d-amphetamine and partially blocked the increase in firing rate.”

“Other postsynaptic alpha 1-antagonists, such as haloperidol, phenoxybenzamine and clozapine, were also effective in blocking this response to d-amphetamine.”

“Either phenoxybenzamine , oxprenolol or halo-peridol, nullify those metabolic effects of d-amphetamine and dopamine, by means of unspecific mechanisms rather than by a specific interaction at drug receptor sites.”