Emetogens

Emetogens are substances that induce vomiting. They work by stimulating the chemoreceptor trigger zone (CTZ) in the brainstem, which is a region that controls the vomiting reflex. The CTZ is located outside the blood-brain barrier, meaning it can be easily accessed by various chemicals in the bloodstream. Emetogens can be ingested, inhaled, or injected.

There are two main types of emetogens: central and peripheral. Central emetogens act directly on the CTZ, while peripheral emetogens stimulate the gastrointestinal tract, which then sends signals to the CTZ. Examples of central emetogens include certain medications like opioids, chemotherapy drugs, and digitalis. Ipecac syrup, which was historically used to induce vomiting in cases of poisoning, is a peripheral emetogen.

The use of emetogens has declined significantly in medical practice. Inducing vomiting is generally not recommended for poisoning unless specifically advised by a poison control center or medical professional, as it can sometimes cause more harm than good. In certain medical situations, such as preparing for surgery or endoscopy, medications that induce vomiting may be used to clear the stomach. However, the primary role of emetogens in medicine has largely been replaced by other treatments.