DESCRIPTION
A competitive serotonin type 3 receptor antagonist. It is effective in the treatment of nausea and vomiting caused by cytotoxic chemotherapy drugs, including cisplatin, and has reported anxiolytic and neuroleptic properties.
CATEGORIES
Antipsychotic Agents
CHEMICAL FORMULA
C18H19N3O
COMPOSITION
Ondansetran 4mg
INDICATION
For the prevention of nausea and vomiting associated with emetogenic cancer chemotherapy, postoperation, and radiation. Also used for the treatment of postoperative nausea and vomiting.
PHARMACODYNAMICS
Ondansetron is a highly specific and selective serotonin 5-HT3 receptor antagonist, not shown to have activity at other known serotonin receptors and with low affinity for dopamine receptors. The serontonin 5-HT3 receptors are located on the nerve terminals of the vagus in the periphery, and centrally in the chemoreceptor trigger zone of the area postrema. The temporal relationship between the emetogenic action of emetogenic drugs and the release of serotonin, as well as the efficacy of antiemetic agents suggest that chemotherapeutic agents release serotonin from the enterochromaffin cells of the small intestine by causing degenerative changes in the GI tract. The serotonin then stimulates the vagal and splanchnic nerve receptors that project to the medullary vomiting center, as well as the 5-HT3 receptors in the area postrema, thus initiating the vomiting reflex, causing nausea and vomiting.
No Information
ABSORPTION
Ondansetron is well absorbed after oral administration and undergoes limited first-pass metabolism.
METABOLISM
Hepatic.
HALF LIFE
5.7 hours
TOXICITY
Low blood pressure and fainting, sudden blindness, severe constipation
FOOD INTERACTIONS
Take without regard to meals.
SIDE EFFECTS
Headache. Feeling tired or weak. Hard stools (constipation). Drinking more liquids, working out, or adding fiber to your diet may help. Talk with your doctor about a stool softener or laxative. Feeling dizzy. Rise slowly over a few minutes when sitting or lying down. Be careful climbing. Feeling lightheaded, sleepy, having blurred eyesight, or a change in thinking clearly. Avoid driving and doing other tasks or actions that call for you to be alert or have clear eyesight until you see how this drug affects you. A faster, harmful heartbeat may rarely happen.