School of Pharmacy and Health Professions, Creighton University Medical Center, Omaha, Nebraska.
Department of Pharmaceutical & Biomedical Sciences, Kitsto Consulting LLC, Frisco, Texas.
Phytother Res. 2020 Aug;34(8):1838-1846. doi: 10.1002/ptr.6649. Epub 2020 Feb 26.
Confusion and misunderstanding exist regarding the lack of cardiovascular and other adverse health effects of p-synephrine and p-octopamine relative to ephedrine and m-synephrine (phenylephrine) which are known for their effects on the cardiovascular system. These four molecules have some structural similarities. However, the structural and stereochemical differences of p-synephrine and p-octopamine as related to ephedrine and m-synephrine result in markedly different adrenergic receptor binding characteristics as well as other mechanistic differences which are reviewed. p-Synephrine and p-octopamine exhibit little binding to α-1, α-2, β-1 and β-2 adrenergic receptors, nor are they known to exhibit indirect actions leading to an increase in available levels of endogenous norepinephrine and epinephrine at commonly used doses. The relative absence of these mechanistic actions provides an explanation for their lack of production of cardiovascular effects at commonly used oral doses as compared to ephedrine and m-synephrine. As a consequence, the effects of ephedrine and m-synephrine cannot be directly extrapolated to p-synephrine and p-octopamine which exhibit significantly different pharmacokinetic, and physiological/pharmacological properties. These conclusions are supported by human, animal and in vitro studies that are discussed.
关于 p-麻黄碱和 p-章鱼胺与已知对心血管系统有影响的麻黄碱和 m-麻黄碱（苯丙醇胺）相比缺乏心血管和其他不良健康影响，存在混淆和误解。这四个分子有一些结构上的相似之处。然而，p-麻黄碱和 p-章鱼胺与麻黄碱和 m-麻黄碱的结构和立体化学差异导致了明显不同的肾上腺素能受体结合特性以及其他机制差异，这些差异已得到综述。p-麻黄碱和 p-章鱼胺与 α-1、α-2、β-1 和 β-2 肾上腺素能受体的结合很少，也不知道它们具有间接作用，导致在常用剂量下内源性去甲肾上腺素和肾上腺素的可用水平增加。这些机制作用的相对缺失解释了它们与麻黄碱和 m-麻黄碱相比，在常用口服剂量下缺乏产生心血管作用的原因。因此，麻黄碱和 m-麻黄碱的作用不能直接推断为 p-麻黄碱和 p-章鱼胺，因为它们表现出明显不同的药代动力学和生理/药理学特性。这些结论得到了讨论的人体、动物和体外研究的支持。
