What Are the Most Common Ondansetron Side Effects?

Ondansetron side effects can range from mild to severe, but the most common effects need only be reported to a physician if they become serious or do not gradually disappear. These include diarrhea, constipation and headache. Some patients also report feeling weak, dizzy, or uncharacteristically tired.

There are other, more severe ondansetron side effects that should be reported to a medical professional immediately. These symptoms are typically the result of a rare allergic reaction to the medication. They can include itching, hives, and the sudden development of a rash. Other more serious effects such as noisy, short, or otherwise troubled breathing have also been reported. Some patients also experience swelling in areas such as the extremities, throat, and tongue.

Other ondansetron side effects can arise as a result of certain conditions the patient may have. The drug may be too high-risk for individuals with liver problems. Those who are following a special diet due to phenylketonuria (PKU) are typically advised not to take the disintegrating tablet form of the drug. Women who are nursing, pregnant, or planning to become pregnant are also usually not able to take the drug.

As a preventative measure against ondansetron side effects, all medication allergies should be discussed with the prescribing doctor before taking the drug. There may be ingredients in ondansetron that are the same as in those drugs that cause an adverse reaction. Patients who are allergic to palonosetron, alosetron, and dolasetron in particular may not be able to take ondansetron. Mixing ondansetron with tramadol may also be problematic, though a doctor may choose to simply adjust the amount of medication instead of completely avoiding the drug.

Ondansetron is usually prescribed to help control the vomiting and nausea associated with certain medical procedures. The drug blocks the effects of a chemical in the body that causes these problems. It is most commonly used along with surgery, chemotherapy for cancer treatment, and radiation therapy.

The proper dosage of ondansetron can also help to prevent adverse effects. It is typically prescribed to be taken from about 30 minutes to two hours before a procedure. Dosage timing depends upon the specific treatment, and it may also be taken during and for a few days after the treatment.

Ondansetron comes in a liquid solution and as fast-dissolving tablets. The tablets are fragile and must be handled with care, particularly when being removed from the packaging. There are no special instructions for the liquid solution, though it is important to ensure that the exact prescribed dosage is taken.