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What Condition Does Ondansetron Treat?

Ondansetron is a serotonin 5-HT3 receptor antagonist. It is an antiemetic medicine used in hospitals to prevent nausea and vomiting due to specific medical treatments. It was approved for medical use in 1990. It’s one of the most commonly prescribed drugs in the US and is listed on the World Health Organization’s list of essential medicines needed in the health system. This medicine is fast-acting. Its onset of action is seen within 30 minutes. Unlike other anti-nausea medications, the side effects of this drug are relatively mild.

What condition does Ondansetron treat?

Ondansetron is a prescription drug that comes in different forms. It’s prescribed for the treatment and prevention of vomiting and nausea caused by medical treatments such as:

How does Ondansetron work?

As a serotonin 5-HT3 receptor antagonist, Ondansetron works by blocking the 5-HT3  receptors in the gut and the central nervous system. During surgery, chemotherapy, and radiation, serotonin (5HT) is released in the body. The 5HT stimulates the serotonin receptors in the brain and gut and causes them to send messages to the brain’s vomiting center. The release of the chemical serotonin in the central nervous system and stomach makes you feel sick and vomit. The Ondansetron stops the 5HT from stimulating the 5HT3 receptors. As a result, no message can reach the vomiting center of the brain. You won’t feel sick, retch, and vomit.

What is the dosage of Ondansetron?

The dose and duration of treatment of Ondansetron are based on the amount and the strength of the medicine.

Prevention of severe nausea and vomiting after chemotherapy:

  • Adult and children 12 years old: Take 24 mg tablet 30 minutes before cancer therapy

Prevention of moderate nausea and vomiting after chemotherapy:

  • Adult and children 12 years old: Take 8 mg tablet 30 minutes before cancer treatment. Take another 8 mg 8 hours after the first dose. Take the next dose every 12 hours for 1 to 2 days.
  • Children 4 to 11 years old: Take 4 mg 30 minutes before cancer treatment. Take another 4 mg every 4 to 8 hours after the first dose, then every 8 hours for another 1 to 2 days.

Prevention of nausea and vomiting after surgery:

  • Adult and children 12 years old: Take 16 mg tablet one hour before anesthesia is given
  • Children: The doctor determines the dose for children.

Prevention of nausea and vomiting after radiation treatment:

  • Adult: Take 8mg tablet one or two hours before radiation therapy. Take another 8 mg every 8 hours.
  • Children: The doctor determines the dose for children.

How to use Ondansetron?

  • Take Ondansetron by mouth exactly as directed by your doctor.
  • The dose is fragile, so you need to remove it carefully from their packaging.
  • If you vomit within one hour of taking the dose, take another one as it may not have been absorbed. If you vomit more than an hour after taking medicine, do not take another dose.
  • Do not chew the tablet.
  • Do not take more or less than what is prescribed.
  • If you forgot to take your dose, take it as soon as you remember unless it’s almost time for you to take your next dose.

What are the precautions in using Ondansetron?

  • Ondansetron can help prevent nausea and vomiting due to cancer therapy, surgery, or radiation. However, it is not effective for treating vomiting caused by motion sickness.
  • This medicine can make you dizzy. Do not drive or do anything that requires mental alertness.
  • Take it exactly as prescribed as high doses can cause heart problems if you are at risk. A high dose of Ondansetron can cause serotonin syndrome, which could be life-threatening. Serotonin syndrome happens when there is too much build-up of serotonin in your body. Symptom may include:
    • Sweating
    • Tremor
    • Agitation
    • Diarrhea
    • Nausea and vomiting
    • Feeling hot
    • Rapid heartbeat
    • Hallucination
    • Muscle rigidity
  • Patients who are taking antidepressants are at higher risk of developing serotonin syndrome. Talk with your doctor if you have been taking antidepressants before you take this medicine.
  • Do not take this if you have:
    • Abnormal heart rhythm called congenital long QT syndrome
    • You are allergic to any of its ingredients
  • Lower dose and extra monitoring are needed if you have:
    • Liver problems
    • Having surgery on the tonsil or adenoids
    • Blockage in the gut or intestinal obstruction
    • Allergic to other 5HT3 medicines
    • Disturbances in the normal level of electrolytes in the blood (magnesium or potassium)
    • Slow heartbeat, heart block, sick sinus syndrome, or irregular heartbeat
  • Pregnant or breastfeeding women should inform their doctor if their pregnant or breastfeeding before taking this medication. Doctors may prescribe this to pregnant women only if other antiemetic drugs have not worked.
  • Ondansetron may interact with other drugs and may cause changes in the way it works. To avoid unwanted interaction, inform your doctor what other medicines you are taking, including those bought without any prescriptions like vitamins, dietary, and herbal supplements.
  • If severe nausea and vomiting continue after leaving the hospital, check with your doctor.
  • In case of severe side effects like an allergic reaction, with signs like a rash, itching, trouble breathing, and difficulty swallowing, seek medical attention right away.
  • If you have started to have swelling and pain in your stomach area, check with your doctor as these may be signs of bowel problems or severe stomach problems.

Price of Generic Ondansetron vs. Zofran

The generic Ondansetron is an effective drug against nausea and vomiting caused by surgery, radiation, and cancer therapy. It’s cheaper than the brand name Zofran. Ondansetron 4mg only costs $1 per tablet or $10.00 per 10 tabs here at Rx2go. The brand name Zofran 4 grams cost $233.80 per 10 tablets or $23.38.

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