Pleiotropy (drugs)

In pharmacology, pleiotropy includes all of a drug's actions other than those for which the agent was specifically developed.^[1] It may include adverse effects which are detrimental ones,^[1] but is often used to denote additional beneficial effects.^[2]

For example,

systemic ones, for the same reason that endogenous steroid hormones do: cells throughout the body have receptors that can respond to them, because the endogenous ones are endocrine

messengers.

Another example is melatonin, which has a wide range of effects on biological systems on multiple scales, from modulating the circadian rhythm and inducing sleep via the activation of melatoninergic receptors, to recepto-independent antioxydative and anti-inflammatory effects over all organs down to cells.[3]^[4]