Prescription Medication Facts Zofran


Zofran, or ondansetron, is an anti-nausea medication known as an antiemetic. It can be prescribed under the brand names Zofran, Zofran ODT and Zuplenz. It works by blocking the chemicals that trigger nausea and vomiting and is most often used after surgeries, along with cancer treatments and to treat vomiting associated with pregnancy. It is extremely effective, but also extremely expensive.

The drug functions by indirectly reducing the activity of the vagus nerve in the brain. That particular nerve located in the medulla oblongata is the “vomiting center.” Zofran also blocks seratonin uptake in the chemoreceptor trigger zone, which communicates with the vomiting center. The drug does not work to curb the effects of motion sickness-related nausea because that form of nausea is caused by dopamine and the muscarinic receptors instead.

Zofran is most often administered intravenously about half an hour before chemotherapy or radiation in cancer patients. For post-operative nausea and vomiting it can be taken orally. It also sometimes helps with acute cases of gastritis and is occasionally used off-label to treat cyclic vomiting syndrome. The most common off-label use is to treat vomiting in pregnant women and also hyperemesis gravidarum. Its safety for use by pregnant women is questionable. Some studies have indicated increased risk of clef palate in babies, but other studies have indicated no risks.

The medication may be a potential treatment for schizophrenia as well. When it is coupled with the common schizophrenia drug, haloperidol, there is a significant improvement in negative symptoms. The drugs in combination also lessen the common negative side effects of haloperidol. It also may potentially be a treatment for the psychosis associated with Parkinson’s disease, but scientists are unsure how this works because zofran does not interact with dopamine and dopamine is associated largely with psychosis. It may also help with obsessive compulsive disorders (OCD), but extensive research has not been conducted. Sometimes it is used to treat irritable bowel syndrome (IBS), which is also controlled by the enteric nervous system. The same mechanisms controlling vomiting are also associated with colon contractions. Postanesthetic shivering also appears to be lessened by zofran.

Most people tolerate this drug easily. It has very few side effects of zofran, but the most common ones are constipation, light headedness and headaches. More severe, but rare side effects are fainting, blurred vision, shortness of breath, anxiety and excessively urination. It also sometimes causes an allergic reaction in people allergic to other seratonin blockers, and it is also possible to be allergic to some of the inactive ingredients. It does not interact negatively with any other drugs, but it might be dangerous for people with a specific type of heart arrhythmia known as Long QT syndrome, but only in high doses. The highest dose of zofran has been pulled from the market by the FDA for this reason.

Zofran was developed in London in 1984. It was approved by the FDA in 1991. It is currently marketed by GlaxoSmithKline simply as Zofran. Pfizer Injectables markets it as Ondanzetron. Several other pharmaceutical companies market their own versions of zofran under a number of different names around the world.