Drugs that cause Nausea or Vomiting
Nausea and vomiting are common side effects of many drugs. But there are some drugs that make people more likely to vomit.
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).
Some medications may affect the VC by locally acting on the gastrointestinal (GI) tract.
1. Drugs acting on chemoreceptor trigger zone (CTZ)
Certain drugs can make you feel like throwing up and vomiting by acting on a part of the brain called the CTZ. This area is sensitive to various substances such as drugs, toxins, and metabolic waste products. When these substances activate the CTZ, it triggers the sensation of nausea and vomiting.
The following are some examples of drugs that can stimulate the CTZ and induce nausea and vomiting:
- Apomorphine
- Emetine (when given parenterally and only at large doses)
- L-DOPA
- Estrogens (morning sickness of pregnancy)
- Ergot alkaloids
- Cardiac glycosides
- Opiates
- Cancer chemotherapeutic agents
Morphine can either induce or block emesis, as it can bind with both emetic and antiemetic opioid receptors. When it comes to feeling nauseous, it's because morphine activates a specific area in the brain called the chemoreceptor trigger zone. And it prevents nausea by suppressing the vomiting center in the brain.
Emetic effect is mediated by delta (δ) or kappa (κ) receptors, whereas antiemetic effect by mu (µ) receptors.
However, we can block both these actions of morphine using naloxone, an antagonist drug used to counteract the effects of opioids (↗️). It mainly targets the receptors responsible for pain relief and the slowed breathing that opioids can cause.
Learn more about narcotic and non-narcotic analgesics (↗️).
2. Drugs acting locally on the GI tract
They activate specific cells, enterochromaffin cells, in the mucosa of the digestive (↗️) or GI tract, causing the cells to secrete a hormone called serotonin. This hormone 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." The following drugs are known to act locally on the GIT:
- 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)
Facts to know:
You need to know that every pharmaceutical preparation, whether it is a pain medication, flu vaccine or a dietary supplement, has a maximum and minimum therapeutic dose.
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 test results. They also assess the lethal dose via rat or animal model studies, though that result is not shared publicly because of patient's safety.
Overdose of any drug can cause a vomiting tendency, but this does not mean you can simply take any medication in higher doses to induce nausea or vomiting. It is essential to take medication as prescribed by your physician to avoid any detrimental side effects.
In summary, I want to say that every drug is a poison, whether it is a herbal or pharmaceutical preparation. If you take your medication as directed by your doctor, it will help treat the condition you're suffering. But if you experiment by overdosing yourself with the prescribed medication, I can only warn you that you run the risk of having some very bad side effects.
Recommended Reading Is herbal remedies really safe? (↗️)
Image source: Jade Jackson, CC-BY-2.0, via Flickr
The information provided in this article is only meant to give you an overview of drugs that can cause nausea or vomiting. You must consult a physician or pharmacist for more specific information regarding any medication you may be taking.
