Heads Up! Major Drug Interaction!

For those on Cabometryx. Heads up!!!!

I started getting nauseous in the mornings again. Doc prescribed Ondansetron (generic Zopharn). That knocked me for a loop so she put me on Prochlorperazine.

I looked up to see if there are any contraindications with taking with Cabometryx (the daily chemo pill). Grok (X’s AI) said that there is a huge contraindication with generic Zophran and a slight risk with Prochlorperazine!!!

“No, it is generally not recommended to take ondansetron (Zofran) and Cabometyx (cabozantinib) at the same time without close medical supervision.

There is a major drug interaction between these two medications. Both can prolong the QT interval on an electrocardiogram (ECG), which measures the time it takes for your heart to recharge between beats. When taken together, they may increase the risk of developing an irregular heart rhythm (such as torsades de pointes), which can be serious or even life-threatening, though this side effect is relatively rare.

This interaction is well-documented in reliable sources like Drugs.com, and clinical reviews for managing side effects of cabozantinib (e.g., nausea) specifically caution about using ondansetron due to this QT prolongation risk.”

“Prochlorperazine, a phenothiazine, is also associated with some risk of QT prolongation and ECG changes, though it is generally considered lower risk compared to some other antiemetics or antipsychotics.

Combining drugs that both prolong QT can additively increase this risk, potentially leading to arrhythmias, especially in patients with other risk factors (e.g., low potassium/calcium, heart disease, older age, or other QT-prolonging meds).”

“Safer alternatives for nausea/vomiting with cabozantinib:

Oncology guidelines and reviews often recommend these options to avoid QT risks:

• Metoclopramide (Reglan) – commonly suggested as a first-line alternative.

• Prochlorperazine (Compazine) or other phenothiazines.

• Lorazepam (Ativan) or other benzodiazepines for anxiety-related nausea.

• Dexamethasone (in some cases, but check for other interactions).

• Lifestyle measures: Small frequent meals, avoiding triggers, hydration.

This is not personalized medical advice. Please discuss with your oncologist or pharmacist immediately—they can review your ECG history, electrolytes, and overall risks to decide if ondansetron can be used safely (perhaps at lower doses) or switch to a better option. They may also monitor you more closely if combination is unavoidable.”

So now you know. You are your best advocate. Question everything and do research from very reliable sources like Grok or Pubmed.