Possible Interaction: Oxymetazoline and Yohimbine

“A concentration (CONCopt) of oxymetazoline and prazosin was calculated from these curves that would optimally antagonize binding of [3H]yohimbine to high-affinity sites, minimally inhibiting low-affinity binding.”

“The percentages of [3H]yohimbine binding that were inhibited by the CONCopt of oxymetazoline and prazosin were determined in numerous brain regions.”

“Moreover, the positive effects of oxymetazoline were attenuated by yohimbine and BRL44408, which are selective alpha2- and alpha2A-adrenoceptor antagonists, respectively.”

“A presynaptically supramaximal concentration of the α-adrenergic agonist oxymetazoline prevented the facilitatory action of yohimbine , but not that of angiotensin II.”

“Both detomidine and oxymetazoline inhibited vagal acid hypersecretion, their effects being fully prevented by idazoxan, 7,8-(methylenedioxy)-14-alpha-hydroxyalloberbane (CH 38083), or 2-(2-methoxy-1,4-benzodioxan-2-yl)-2-imidazoline (RX 821002), and partly antagonized by yohimbine or rauwolscine.”

“The emesis induced by oxymetazoline , tramazoline, xylazine, naphazoline and epinephrine was also antagonized by a selective alpha-2 adrenoceptor antagonist, yohimbine , but not by a selective alpha-1 adrenoceptor antagonist, prazosin.”

“Activation of the enzyme by oxymetazoline was prevented by either the alpha 1-adrenergic antagonist prazosin or the alpha 2-adrenergic antagonist yohimbine and was mimicked by the calcium ionophore A23187.”

“3 The α1‐adrenoceptor agonist, oxymetazoline and the antagonist prazosin inhibited the binding of [3H]‐yohimbine to rat cortex in a complex manner consistent with an interaction at more than one site.”

“4 Yohimbine (0.03–1.0 μM) and phentolamine (0.1–5.0 μM) shifted to the right the concentration‐response curve of oxymetazoline for the inhibition of [3H]‐noradrenaline overflow in response to nerve stimulation without depressing the maxima.”

“5 Yohimbine (0.1 μM) also antagonized the decrease induced by oxymetazoline in the postsynaptic responses to nerve stimulation.”

“The antisecretory effects of oxymetazoline and clonidine given intracerebroventricularly were antagonized with yohimbine administered by the same route.”

“ Yohimbine readily blocked the inhibitory effects of clonidine, oxymetazoline and noradrenaline in both tissues but was less effective against dopamine and apomorphine.”