Can You Take Zofran (Ondansetron) With Your Antibiotic?

Answer

Zofran (ondansetron) can be taken safely with most antibiotics and co-administration is often recommended in certain situations. Having said that, caution is strongly urged with certain antibiotics that can potentially cause QT prolongation, a type of arrhythmia.

What Is Zofran?

Zofran (ondansetron) is an effective antiemetic medication that is used for a variety of indications including:

• Nausea related to chemotherapy
• Nausea related to radiation therapy
• General symptoms of nausea and vomiting

Zofran (ondansetron) works by antagonizing the 5HT3 receptors (serotonin type 3 receptor). Serotonin is a neurotransmitter that plays an important role in the perception of nausea and emetogenic (i.e. inducing vomiting) pathways. Serotonin type 3 receptors are located all over the body, particularly in the GI tract. Antagonizing these receptors is very effective in reducing or eliminating nausea and vomiting symptoms.

Zofran (ondansetron) is generally well tolerated but is rarely associated with QT prolongation and other arrhythmias. Monitoring is recommended in patients that are at higher risk of arrhythmias or are taking other medications that can cause QT prolongation. If it is possible, avoid the use of Zofran and other drugs that can cause QT prolongation.

Below, we list the most common classes of antibiotics and whether or not they are safe to use with Zofran (ondansetron):

Antibiotics That Are Safe To Use With Zofran

• Penicillin class antibiotics

• Amoxicillin
• Penicillin

• Cephalosporin class antibiotics

• Cephalexin
• Cefdinir
• Cefprozil

• Clindamycin

• Tetracycline

• Nitrofurantoin 

There are no known interactions between Zofran and any of the above antibiotics.

Antibiotics That Should be used Cautiously With Zofran

• Bactrim (Sulfamethoxazole)

• Levaquin (levofloxacin)

• Cipro (ciprofloxacin)

• Azithromycin

• Erythromycin

The antibiotics above (aside from Bactrim) can cause a type of arrhythmia known as QTc prolongation. Combining multiple drugs with the potential for QTc prolongation may lead to an additive prolongation of the interval and is a significant risk factor for the development of torsades de pointes (TdP), a potentially fatal ventricular arrhythmia.

Bactrim can interfere with Zofran, increasing its concentrations in the body, which could increase the risk of side effects.

Now, the above antibiotics can sometimes be used with Zofran if they represent the best treatment option for you, but be sure not to combine them unless directed by your doctor.

Final Words

The lists above aren't intended to be a complete list of all antibiotics, but it gives you a good idea of what is considered OK to use with Zofran and which should be used with caution.

So, to summarize, the answer to the question of whether or not antibiotics are safe with Zofran is dependent on the antibiotic used. Be sure to check into your prescribed antibiotic and see if it is associated with QT prolongation or other arrhythmias.

If you have a question about a specific antibiotic I don't have listed above, please feel free to reach out to us!