Category: Antiemetic
Introduction:
Ondansetron is an antiemetic (to prevent vomiting or nausea) medication. It functions by preventing the action of brain chemical messenger serotonin, which result in nausea and vomiting during chemotherapy or following surgery for cancer.
Uses:
How To Consume:
Ondansetron should be taken as per prescribed by a doctor. There are several forms of Ondansetron available for oral administration, including tablets, films, and quickly disintegrating (dissolving) tablets. This medicine is applied to the tongue and dissolved. Unlike other tablet forms, it is not meant to be chewed or consumed.
Ondansetron can be taken with or without food.
Regular Tablet - Take with a full glass of water.
Disintegrating Tablet : Take the tablet out of its packaging, just before taking your dosage. To open the package, do not try to push the tablet through the foil backing of the blister. Instead, use dry hands to peel back the foil backing. Take out the tablet gently and set it on top of your tongue right away. The tablet will dissolve in a few seconds and can be swallowed with saliva.
Duration Between Two Dose:
Ondansetron is taken 4mg every 6 hours when required. Maximum 20mg in 24 hours. 4mg every 6 hours when required.
Note: Patients over 75 years of age or those with significant hepatic impairment should lower their maximum dosage to 8 mg.
Side Effects:
Some common side effects can be seen after taking ondansetron:
Headache
lightheadedness
dizziness
Drowsiness
Tiredness
constipation
Injection site reactions (pain, swelling, redness)
Drug Mechanism:
Pharmacokinetics:
Ondansetron undergoes rapid absorption from the GI tract, and the peak plasma concentration (Tmax) is approximately 1.5 hours after an 8 mg single oral dose. The absolute bioavailability of ondansetron after oral administration is approximately 60%(50%-70%). Tissues contain large amounts of ondansetron and its metabolites. The principal(main) location of metabolism is the liver. Hepatic metabolism accounts for nearly 95% of ondansetron clearance, and less than 5% is excreted unchanged in the urine.
Pharmacodynamics:
Ondansetron is a selective antagonist of the 5-HT3 subtype of serotonin receptors. Ondansetron prevents and treats nausea and vomiting by acting both centrally and peripherally. Central effects are mediated by the antagonism of 5HT-3 serotonin receptors in the area postrema which contain "chemoreceptor trigger zone.". his zone senses neurotransmitters like serotonin, toxins, and other signals and plays a role in mediating the sensation of nausea and subsequent vomiting. Because ondansetron acts on the vagus nerve, it also has peripheral effects. It acts on the 5-HT3 receptors present in the terminals of the vagus nerve. The vagus nerve is sensitive to GI tract stimulants that cause nausea and vomiting. It creates connections in the brainstem's nucleus tractus solitarius, another area crucial for vomiting. Ondansetron's antiemetic effects are mostly assumed to be mediated through its peripheral activities.
Safety Measures :
When to See Doctor:
drowsiness and sedation,
fast or pounding heartbeats
severe constipation, stomach pain, or bloating
jaundice (eye or skin yellowing)
blurred vision or temporary vision loss
hallucinations (hearing voices or seeing things that are not there)excessive sweating
If conditions from this occur you should see the doctor or it can be hazardous for your health if not cured as soon as possible.
Allergic Reaction:
This drug can cause severe allergic reactions. Symptoms include:
rash
hives
itching
Inflammation of the hands, feet, ankles, neck, lips, eyes, or lower limbs
loss of coordination
stiff or twitching muscles
seizures
Immediately go to the doctor if these symptoms occur.
Available Dosage Form:
Form:
Tablet
Strengths: 4mg, 8mg
Injections
Strengths: 0.15 mg/kg IV (max- 16 mg per dose)
Child Dosage
Age- 4 to 11 years age
4 mg is given every 12 hours for a period of one to two days.
Age- 12 years age
8 mg is given every 12 hours for a period of one to two days.
Age- younger than 4 years of age
Use and dose must be determined by your doctor
Adult Dosage-
8 mg is given every 12 hours for a period of one to two days.
Important Note:
Follow the doctor's prescription for the entire course of therapy; do not miss a dosage.Take the missed dose of this medication as soon as you remember if you feel nauseated or throw up after missing one.
Till the time comes to use it, keep the medication in the foil packet.
Try to consume little, healthful snacks throughout the day instead of large, filling meals. In order to assist prevent dehydration, sip water frequently.
Before using this drug, disclose to your chemist or doctor any medical history you may have, particularly with regard to liver illness, irregular heartbeat, and stomach/intestinal issues (such as ileus, edoema, or recent abdominal surgery).
Various Brands:
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