What Is Ondansetron (Zofran)?

Ondansetron (Zofran) is a prescription medicine used to treat nausea and vomiting. It is primarily used to treat nausea and vomiting that occur due to surgery, chemotherapy, and radiation. The medication is available in several forms, including as a liquid, orally disintegrating tablet, regular tablet, and intravenous solution. Tablets of ondansetron typically come in strengths of either four or eight milligrams. Patients on ondansetron should inform their doctor as soon as they can if they experience any unusual or worrying symptoms after taking it.

The major uses, side effects, precautions, details on dosages, and potential medication interactions associated with ondansetron are outlined below.

How It Works

Ondansetron was first developed in 1992, and it is classified as a serotonin 5-HT3 receptor antagonist. Other drugs in this category include apomorphine, palonosetron, dolasetron, alosetron, and granisetron. These medications work by blocking the action of serotonin, a neurotransmitter that can trigger nausea and vomiting. Ondansetron is selective, and it only blocks a small portion of the normal activity of serotonin. When serotonin activity is reduced, patients are less likely to experience nausea and vomiting. Ondansetron only works if it is taken before surgery, chemotherapy, or radiation.

Uncover the major uses of this medication next.

Ondansetron (Zofran) Uses And Benefits

Ondansetron is taken before surgery or cancer treatment to prevent nausea and vomiting. In addition to this approved use, some doctors have prescribed ondansetron to pediatric patients for the treatment of stomach problems. It is frequently prescribed 'off-label' to ease morning sickness during pregnancy. However, recent studies have suggested the medication may be associated with birth defects in unborn children, and this possibility is currently being investigated. Ondansetron is sometimes considered in the treatment of alcohol misuse. It can help prevent the nausea and vomiting that typically occur during withdrawal from alcohol. Doctors might also prescribe it to treat nausea and vomiting that has already started.

Get familiar with the potential side effects of ondansetron next.

Potential Side Effects

Potential side effects of ondansetron include confusion, dizziness, fever, and shortness of breath. Patients could experience an increased heart rate, and weakness may develop. Other common side effects include constipation, diarrhea, blurry vision, skin rashes, and muscle spasms. Although less common, decreases in urinary frequency and volume have occurred. Breathing difficulties, swallowing issues, dry mouth, and loss of appetite are examples of possible rare side effects. Patients should report any stomach pain, muscle spasms, or vision changes to their healthcare professional immediately, and they should seek emergency medical care if they develop chest pain, an irregular heartbeat, severe dizziness, or muscle twitches. Emergency care is also necessary if the patient develops hallucinations or unusual agitation.

Discover some precautions to keep in mind when taking ondansetron next.

Precautions To Remember

Before taking this medication, patients should inform their doctor about any history of liver disease, long QT syndrome, low potassium, congestive heart failure, or intestinal blockages. The doctor will also need to know if the patient has phenylketonuria. Patients who are allergic to dolasetron, granisetron, or palonosetron should not use ondansetron. This drug can be taken with or without food, and the regular tablet should be taken with a full glass of water. The liquid form of ondansetron should be dosed with the provided dosing syringe, and it must be stored in an upright position. Patients using the disintegrating tablet should peel back the foil on the blister pack when it is time for their dose. Using dry hands, they should remove the tablet from the package. The tablet should be allowed to dissolve in the mouth, and patients should not chew it. After the tablet dissolves, the patient should swallow several times.

All forms of this medicine need to be stored away from light, heat, and moisture. Since ondansetron could impair the patient's reaction time, experts suggest individuals who use it refrain from driving or operating heavy machinery until they have had time to determine how the medication affects them. Ondansetron should be used with caution during pregnancy, and some experts believe pregnant individuals should only take it as a last resort. Doctors do not know if ondansetron passes into breastmilk, and patients who are breastfeeding should discuss the risks and benefits of ondansetron with their doctor.

Learn about the potential medication interactions next.

Potential Medication Interactions

Ondansetron is associated with nearly three hundred potential medication interactions. Patients should not use this medication during treatment with apomorphine, and it is known to interact with other serotonin 5-HT3 antagonists as well. Ondansetron can interact with a pain medication called tramadol, and it affects certain types of anticonvulsants, including phenytoin. It can interfere with antidepressants, beta-blockers, antipsychotic medicines, and drugs that reduce heart rate. Patients who take these drugs should ask their doctor whether it is safe for them to use ondansetron or whether they will need to take a different medicine. Since there are so many potential medication interactions that could occur with ondansetron, patients should ask their doctor to review their complete medication list for possible interactions before ondansetron is prescribed. They should also ask their pharmacist to double-check this list for potential issues before dispensing the drug.

Read about when doses of ondansetron need to be taken next.

When To Take Doses

Patients undergoing chemotherapy typically take one dose approximately thirty minutes before each chemotherapy session. Individuals who use ondansetron during radiation treatment are often advised to take a dose one to two hours before their appointment. When used before surgery, patients usually take it one hour before their operation. An adult dose can range from sixteen to twenty-four milligrams. Patients should read the medication label carefully before taking ondansetron. At times, patients might be asked to take their very first dose of this medicine at a clinic so they can be monitored by medical staff. The intravenous solution of ondansetron must be administered at a hospital or in a clinical setting, and patients usually receive the first dose as an infusion over a fifteen-minute period. The dose is based on the patient's weight, and doctors usually start with a dose of 0.15 milligrams per kilogram of body weight. The maximum dose for the intravenous solution is sixteen milligrams.