Ondansetron is basically a medication that prevents vomiting and nausea in patients post surgery or after chemotherapy and radiation for cancer treatment. Chemical actions that trigger nausea and vomiting are blocked by taking ondansetron.
Before the doctor starts you on ondansetron he should be informed if you are allergic to ondansetron and related medicines like, alosetron (Latronex), dolasetron (Anzemet), granisetron (Kytril), palonosetron (Aloxi) or to any of the other components that could be part of the tablet or liquid form of ondansetron. The pharmacist could provide you with a list on request.
Inform the doctor also if you are taking any vitamins, nutritional supplements or herbal products and also any other prescribed and non-prescribed medications you might be taking so the doctor can change the dosage of your medicines and also monitor you for possible side effects.
Inform the doctor in case of pregnancy or likelihood of pregnancy or if you are breast feeding. If you become pregnant while on ondansetron tell the doctor immediately.
If you suffer from phenylketonuria commonly known as PKU, which is a condition where a special diet is required to prevent mental retardation and is an inherited disease.
Ondansetron is used to prevent any nausea or vomiting after chemotherapy or radiation therapy for the treatment of cancer. It is also given after surgery to prevent vomiting so there is no strain to the surgical stitches on vomiting. Ondansetron blocks serotonin which is a natural substance found in the body and it induces vomiting.
Ondansetron is available in the form of a oral solution and a tablet that dissolves rapidly in the mouth when taken. A person being treated for chemotherapy is given the first dose 30 minutes prior to the start of chemotherapy. It is given 1 to 2 hours before radiation or surgery.
For chemotherapy and radiation patients sometimes an additional dose of ondansetron is required to be given one to three times a day and also 1 to 2 days after the treatment ends. The doctor's direction should be followed to the dot. Neither should the medication be taken too often nor should the dosage be changed. Get the pharmacist to explain any prescription label details that are not understood.
If you are taking the dissolving tablet then remove the tablet from the package just when you are ready to use it. Do not push the tablet through the foil backing but peel back the foil backing with completely dry hands and immediately place the tablet on the tongue. The tablet will begin to dissolve immediately and will automatically get swallowed with saliva.
The vomiting centre in the brain controls vomiting as it is responsible for causing feelings of nausea and reflexive vomiting. The vomiting centre gets activated on receiving messages from the nerves in the area known as chemoreceptor trigger zone (CTZ) and also nerve messages from the gut.
When ondansetron is administered the medication does not allow the CTZ site and the nerve pathways that carry the messages to work properly to stimulate vomiting. These receptors in the CTZ in the brain are also known as 5HT3. When chemotherapy, radiotherapy and surgery take place a substance known as serotonin, 5HT gets released in the gut. The 5HT acts on receptors (5HT3) in the gut and this causes nerves to send messages to the vomiting centre. When 5HT activates 5HT3 receptors in the CTZ in the brain further messages are sent to the vomiting centre.
Ondansetron blocks the 5HT3 receptors in the brain and the gut and so the nausea messages are not sent from the brain and gut to the vomiting centre. Ondansetron thus works in preventing nausea, retching and any sickening feeling to occur as a result of surgery, chemotherapy or radiotherapy used in cancer treatment.
Ondansetron is available as a tablet, syrup and injection and has ondansetron hydrochloride dehydrate as an active ingredient. Ondansetron is available without a brand name as a generic medicine also. In tablet and syrup form it is given orally and is also injected into the muscle or vein. It is also used in a drip infusion (intravenous) and also by suppository.
Some herbal medicines like St. John wort may cause serotonin to increase and so combining it with ondansetron would not be advisable. Ginseng might also work as a MAO inhibitor and should also be avoided. Potential urge to vomit on consuming excessive alcohol and possible sedation are two reasons to avoid alcohol. Besides, any potential liver damage due to abuse of alcohol could limit the total dose of ondansetron to be taken. Smoking marijuana results in side effects like sedation, additive antiemetic effects may occur.
Ondansetron is discontinued on completion of the three day prescribed course after therapy.
The tablets are to be stored either in the refrigerator or at room temperature between 36-86�Fahrenheit whereas the liquid must be stored only at room temperature. Ondansetron must not be exposed to any humidity and kept away from light. Do not store the medicine in the bathroom but keep it out of reach of children and pets. The medication must not be flushed down the toilet or poured in to the drain unless instructed to do so by the local waste disposal company or the pharmacist who should be consulted on the safe disposal of the medicine once it has reached expiry period or when not needed any more.