Are you sure the drugs you are taking may not cause nausea or vomiting?
I believe you never thought about that. But, believe me or not, nausea or vomiting is the most common side effect of almost every drug!
Overdose of any drug can cause a vomiting tendency; improper administration of any medication can exert serious adverse reactions and may even cause death.
Every pharmaceutical preparation -- whether it is a vaccine or supplement -- has a maximum and minimum therapeutic concentration. Researchers working in the manufacturing company and regulatory agency evaluate the optimum effective dose of a drug based on both in vivo and in vitro laboratory test results. They also assess the lethal dose via rat or animal model studies, though that concentration is not shared publicly because of patient's safety.
In brief, I want to say that every drug is a poison, no matter it's a herbal or pharmaceutical preparation. If you take your medications properly -- as prescribed by your physician, they can provide you with healthy benefits. But if you misuse or abuse what is prescribed, then all I can say you're in risk of some potential side effects.
However, there are certain drugs that can trigger vomiting tendency. Studies suggest that drugs inducing nausea or vomiting potentially work on two regions in the nervous system: the chemoreceptor trigger zone (CTZ) and the vomiting center (VC).
1. Drugs acting on chemoreceptor trigger zone (CTZ)
- Emetine (when given parenterally and only at large doses)
- Estrogens (morning sickness of pregnancy)
- Ergot alkaloids
- Cardiac glycosides
- Cancer chemotherapeutic agents
- Cardiac glycosides
2. Drugs acting locally on the G-I tractThey activate specific cells, enterochromaffin cells, in the mucosa of the digestive tract or gastro intestinal tract (GIT or GI tract), causing the cells to secrete a hormone, serotonin, which acts on the receptors at the nerve endings of the vagal sensory fibers. The afferent fibers transmit excitation to the N. tractus solitarius, which in turn activates the vomiting center in the brain. These drugs are traditionally called "local irritants".
- Ipecac (the most useful household emetic is syrup of ipecac; emetine is one of its active ingredients)
- Zinc salts
- Copper sulfate
- Antimony salts ("tartar emetic" is antimony potassium tartrate)
Image source: Jade Jackson, CC-BY-2.0, via Flickr