emetines

Emetine is a naturally occurring isoquinoline alkaloid derived from the root of ipecacuanha (ipecac), traditionally along with cephaeline. It has historically been used both as an emetic to induce vomiting after ingestion of poisons and as an antiamoebic agent for amoebiasis. The emetic effect is attributed to stimulation of the stomach lining and to activation of the central vomiting center; the precise mechanism is not fully understood and may involve multiple pathways.

In addition to its emetic action, emetine exhibits antiparasitic activity, particularly against Entamoeba species. Its antiamoebic effect is thought to involve inhibition of protein synthesis in the parasite by binding to ribosomes, though selectivity for the parasite over human cells is limited. Because of this narrow therapeutic window and potential toxicity, the drug is now used only under strict medical supervision in some settings, and related compounds have largely supplanted its routine use.

Safety concerns are dominated by cardiotoxicity; even therapeutic doses can cause serious cardiac effects such as arrhythmias or cardiomyopathy, and interactions with other medications affecting cardiac conduction can occur. As a result, emetine is not recommended for routine emesis or self-treatment, and many ipecac-based products have been withdrawn or discouraged in clinical practice. In modern amoebiasis management, alternative therapies are preferred, with emetine-containing regimens occurring only in carefully controlled contexts.