Anti-emetic drugs are widely used to prevent vomiting and nausea in patients undergoing chemotherapy, radiation therapy, and surgery.

These drugs work by blocking dopamine and serotonin receptors in the brain that are responsible for triggering the vomiting reflex. While anti-emetics are generally considered safe, there is growing evidence that some of these drugs may increase the risk of stroke, particularly in patients who are already at risk of cardiovascular disease.

What Are Anti-Emetic Drugs?

Anti-emetics fall into four general categories: dopamine antagonists, serotonin antagonists, neurokinin-1 receptor antagonists, and corticosteroids.

Dopamine antagonists, such as metoclopramide and domperidone, are the oldest and most widely used anti-emetics. These drugs block dopamine receptors in the brain, which reduces nausea and vomiting in patients undergoing chemotherapy or surgery.

Serotonin antagonists, such as ondansetron, granisetron, and palonosetron, are newer anti-emetics that are more selective than dopamine antagonists. These drugs block serotonin receptors in the brainstem, which regulates nausea and vomiting.

The neurokinin-1 receptor antagonist, aprepitant, is used in combination with other anti-emetics to prevent delayed nausea and vomiting in patients receiving chemotherapy. Corticosteroids, such as dexamethasone, are potent anti-inflammatory drugs that also have anti-emetic properties.

How Do Anti-Emetics Increase Stroke Risk?

The exact mechanism by which anti-emetic drugs increase stroke risk is not fully understood. However, some studies suggest that certain anti-emetics may promote blood clotting and increase blood pressure, both of which are risk factors for stroke.

Dopamine antagonists, in particular, have been shown to increase blood pressure, heart rate, and platelet aggregation in healthy volunteers and animal models. These effects may be more pronounced in patients with pre-existing cardiovascular disease or risk factors, such as hypertension, diabetes, or smoking.

Which Anti-Emetics Are Associated with Stroke Risk?

Several studies have identified a possible link between anti-emetic use and strokes, particularly in patients undergoing chemotherapy for cancer.

A meta-analysis of 17 studies involving over 154,000 patients found that the use of dopamine antagonists increased the risk of stroke by 28% compared to placebo. Ondansetron, a commonly used serotonin antagonist, has also been implicated in stroke cases, although the evidence is less clear. Other anti-emetics, such as aprepitant and corticosteroids, have not been associated with increased stroke risk.

How Can Stroke Risk Be Reduced in Patients Who Need Anti-Emetics?

While it is important to be aware of the potential risks associated with anti-emetic use, it is also important to recognize that these drugs can provide significant relief to patients who are at risk of vomiting and nausea.

Therefore, the decision to use anti-emetics must be made on a case-by-case basis, taking into account the patient’s individual risk factors and medical history.

In general, patients who have a history of stroke, heart disease, or other cardiovascular risk factors should be monitored closely when receiving anti-emetics, and alternative treatments may be considered if the risk of stroke outweighs the benefits of anti-emetic therapy. Patients who are already taking anti-platelet or anticoagulant drugs, such as aspirin or warfarin, may also be at increased risk of bleeding if they receive anti-emetics that promote blood clotting.

Conclusion

In summary, anti-emetic drugs are widely used to prevent vomiting and nausea in patients undergoing chemotherapy, radiation therapy, and surgery.

While these drugs are generally safe, certain anti-emetics, such as dopamine antagonists and ondansetron, may increase the risk of stroke, particularly in patients who are already at risk of cardiovascular disease. Therefore, physicians must carefully weigh the risks and benefits of anti-emetic therapy in each individual patient, and monitor patients who receive anti-emetics for signs of stroke or other adverse events.