What is Ondansetron Used For?

Introduction

Ondansetron helps in blocking the actions of the various chemicals (one of which being serotonin) in the body, which mostly lead to triggering of vomiting and nausea. Hence, we can say that Ondansetron is used for preventing the instances of nausea and vomiting which could have been caused due to radiation therapy, surgery or chemotherapy treatment. However, Ondansetron can also be used for other purposes which are not listed above.

Ondansetron is part of the class of medications which are called as serotonin 5-HT3 receptor antagonists.

Precautionary Measures

• Ondansetron should not be used if the individual is already on apomorphine (Apokyn) or if one is allergic to Ondansetron or to any of its ingredients. Also, if one is allergic to similar medicines such as granisetron, dolasetron or palonosetron.
• Before starting off with the treatment, let the doctor know if you are suffering from liver disorder or there is any family history or personal medical history of Long QT syndrome.
• The oral disintegrating tablet form of Ondansetron may possibly contain phenylalanine, hence it is important to let the doctor know if you are suffering from phenylketonuria or PKU.
• There can be cases of serious side effects of using Ondansetron which would include blurry vision or a temporary loss of vision which would last for few minutes and it can go up to several hours. The heart rate can also slow down, individual may have trouble while breathing, shivering, there would be a feeling as if the individual would pass out any moment, anxiety attacks, there would be dip in the amount of urine. In such cases, it is better to reach out to the doctor immediately.
• Ondansetron can also impair the thinking as well as reactions, hence one should be careful while driving or carrying out any activity which would need mental alertness.

Before Usage

It is very important to understand when one should consume the medication and all the precautions should be taken while starting any treatment. Below are few details an individual should keep in mind before starting any course of treatment of Ondansetron.

• An individual should not consume Ondansetron if they are also taking in apomorphine or they are allergic to Ondansetron or any of its similar medicines.
• Inform the doctor before starting the treatment if one is suffering from liver issues, heartbeats going slow, a family history of long QT syndrome, an electrolyte imbalance which can include dip in the potassium levels or magnesium levels in the blood and a blockage in the digestive tract such as stomach or intestines.
• Ondansetron mostly would not harm the unborn baby, but if you are pregnant or planning of conceiving, then do inform you doctor.
• Let the doctor know if you are nursing a baby since it is yet not known what effect Ondansetron can do if it passes on into the breast milk.
• Ondansetron is not to be given to anyone who is younger than four years old.

Usage

An individual should take Ondansetron by following the exact directions provided by the doctor, else you can refer to the instructions on the prescription label. Avoid taking Ondansetron in more than the required dosage or lesser dose amounts. Ondansetron can be taken either with or without food. The first dose of Ondansetron is mostly taken prior to the start of the surgery, cancer related chemotherapy or radiation treatments. It is important to follow the dosing instructions mentioned by the doctor. Ondansetron should be taken on a regular basis along with a glass of full water.

Follow the below procedure to take the oral disintegrating tablet form of Ondansetron Zofran ODT:

• Until you are ready for consuming this tablet, it should be kept in the blister pack itself.
• Once you are ready, then open the package and peel the foil, however ensure that you do not push the tablet through the foil else it can lead to damaging the tablet.
• While removing the tablet, ensure that your hands are dry and then place it in the mouth.
• Do not instantly swallow the tablet as a whole. First, let it dissolve in the mouth without chewing it.
• As the tablet gradually starts dissolving in the mouth, then swallow the tablet.

Follow the below procedure to take the oral soluble film of Ondansetron in the brand name called as Zuplenz:

• Until you are ready for using this medicine, you can keep the strip of this medicine in the foil pouch itself.
• Ensure that your hands are dry before removing the strip. Now, slowly remove the strip of the medicine from the foil and place it on the tongue.
• The moment you place it; it will start to dissolve.
• Avoid swallowing the medicine strip entirely, it should first get properly dissolved in the mouth without chewing it.
• Once the medicine strip dissolves, you can swallow it. If needed, you can also drink some liquid so as to make it easier for the medicine to get swallowed.
• After using Zuplenz, ensure to wash your hands properly.

While using the liquid solution of the medicine, it is important to measure the liquid with the help of the dosing syringe which has been provided. Medicines should be stored at room temperature and away from light, heat and moisture. In case of the liquid solution of the medicine, it should be stored in an upright position.

If you miss a dose, you can take it as soon as you remember, but if it is almost time for the next dose, then it is preferable to skip the missed one. Avoid taking extra doses of the medicine else it can lead to overdose. Few of the symptoms related with Ondansetron overdose are sudden loss of vision, fainting, severe instance of constipation and feeling lightheaded.

For preventing nausea which is caused due to chemotherapy session, it is advisable to take the medication orally mostly within a period of 30 minutes before starting the chemo treatment. For preventing the nausea issue caused due to radiation therapy, take this medicine orally one or two hours prior to starting the therapy sessions. For preventing the feeling of nausea post the surgery, one can take Ondansetron orally at least an hour before starting the surgery. This medicine can be taken with or without food, but the doctor would advise to not eat before chemotherapy, surgery or radiation.

Ondansetron can be taken at the most three times a day for a period of one to two days after the chemotherapy session or completion of radiation therapy. If one is taking this medicine on a prescribed schedule, then ensure to take it on a regular basis so as to gain maximum benefit from it. Also, it would help to remember the timing of the medicine at the same time each day. The dosage of the medicine is completely based on individual’s age, the medical condition, severity of the medical condition and the body’s response to the treatment. In case of children, the doctor would decide the dosage based on the age and the weight of the child. The usual form of maximum dosage in patients suffering from liver disorder would be 8 mg in a span of 24 hours.             

Dosing

Below are the details for adult dosing given for nausea and vomiting (with chemotherapy induced and without as well):

• Highly Emetogenic Cancer Chemotherapy or HEC: the recommended dose is 24 mg to be taken 30 minutes before the start of the single day HEC.
• Moderately Emetogenic Cancer Chemotherapy or MEC: the recommended dose is 8 mg to be taken twice on a daily basis wherein the first dose should be administered at least 30 minutes prior to starting the chemotherapy session and the subsequent dose can be given after eight hours, after which 8 mg of dose should be given orally two times in a day. Gap between each dose should be 12 hours and it should be continued for one or two days post the completion of the chemotherapy.
• Parenteral: the recommended dose is 0.15 mg IV with the first dose. It should be infused over 15 minutes. It should be given 30 minutes before starting the emetogenic chemotherapy session and the subsequent dose should be given four and then eight hours post the first dose. The maximum dose can be 16 mg per dose.

Storage

Ondansetron should be kept out of reach of children. It is advisable to store the tablets as well as the rapidly disintegrating tablets away from light and at normal room temperature. Those medicines which are not needed should be disposed of in a special way so that no one else should consume it. Do not flush the medicine down the toilet. Instead, the best way of disposing the medicine is through a medicine take back program wherein you can talk to your doctor and contact their local garbage or disposal department for taking back the unused medicine.

Side Effects

Medicines do come with their own pros and cons, hence the individual should discuss well with the doctor about any kind of potential side effects so as to avoid any untoward incidences.

For those individuals who come across allergic reactions by using Ondansetron such as chills, hives, finding it difficult to breathe, rashes on the skin and swelling of the throat, lips, face and tongue, then they should reach out to the doctor immediately.

Below are few of the common side effects which individuals taking Ondansetron may experience,

• Headache
• Constipation
• Feeling of tiredness or weakness
• Diarrhea
• Drowsiness

Below are certain serious types of side effects which few individuals may experience:

• Pounding of the heartbeats
• Irregular heartbeats
• Pain in the stomach
• Loss of vision for temporary period which can be either for few minutes or for several hours
• Severe form of constipation
• Fainting
• Loss of coordination
• Bloating
• Severe case of dizziness
• Blurry vision
• Yellowing of the skin or eyes similar to jaundice.

There can also be cases of increase in the levels of serotonin in the body and it would lead to symptoms such as fever, hallucinations, nausea, fainting, agitation, or overactive reflex.

Drug Interactions

The doctor would most likely be aware of the possible drug interactions and hence they would accordingly monitor your health for the same. One should not start, stop or change the dosing of any of the medicines before first consulting the doctor. Apomorphine should not be used along with Ondansetron, else it can lead to serious case of drug interactions. In case one is already using this medicine, then they should inform the doctor before starting with Ondansetron. Before the doctor starts the medicine Ondansetron, it is always better to inform the doctor about any medications being taken whether prescribed or over-the-counter, if there are vitamins, dietary supplements or herbal supplements being taken.

Ondansetron is known to also cause serious case of heart related problems, especially if certain medicines are used along with it which would also include antidepressants, medicines for treating cancer, antibiotics, HIV or AIDS medicines, heart rhythm medicines, antipsychotic medicines and medicines for treating malaria.

Also, taking Ondansetron along with certain other medications can lead to a rise in the levels of serotonin. This would lead to build up of serotonin in the body and lead to a condition called as serotonin syndrome, which if ignored can turn out to be fatal. Hence it is important that if you are using any of the below mentioned medicines, then let the doctor know of the same at the earliest.

• Opioid medicine or narcotic medicine
• Medicine for treatment of anxiety and depression
• Other medicines for treating nausea and vomiting
• Medicines for treating a psychiatric disorder

Medicines such as procainamide, sotalol, dofetilide, procainamide, pimozide and amiodarone are known to cause an impact to the heart rhythm, if taken along with Ondansetron. It is better to maintain a list of all the medicines which are being taken and share the same with the doctor so that you do not miss out on any medicine while talking to the doctor.