Ondansetron

Ondansetron 60 tabs x 8 mg
Substance

Indications:

Prevention and elimination of sickness and vomiting induced by cytotoxic chemotherapy (primary and repeated courses, including the use of high doses of cisplatin) and radiotherapy (total body surface irradiation, single high-dose irradiation or partial daily abdominal area) in cancer prophylaxis and removal of nausea and postoperative vomiting in surgery, ophthalmology.

Contraindications:

Hypersensitivity to any component of the medication, pregnancy and lactation; children: chemotherapy and radiation - up to 4 years; anesthesia - up to 12 years; hepatic insufficiency.

Administration:

Cytostatic therapy dosing regimen is adjusted individually depending on the severity of vomiting.

Adults and children over 12 years intake initially 8 mg with 1-2 hours to antitumor therapy with subsequent administration of 8 mg over 8-12 hours yet. For prophylaxis of nausea and prolonged vomiting after first 24 hours the administration of the preparation will be extended by 8 mg every 12 hours. The partial irradiation with high-dose on the abdominal region the administration will be by 8 mg every 8 hours. The drug is administered during chemotherapy and radiotherapy cure, also 1-2 days (on requirement - 3-5 days) after finishing them.

Adults and children over 12 years administer 24 mg ondansetron (along with dexamethasone phosphate) 1-2 hours before chemotherapy. For prophylaxis of delayed emesis in the coming days - by 8 mg 2 times a day during the entire course of chemotherapy, also 5 days after finishing it.

Chemotherapy in children aged 4-12 years is administered internally initially by 4 mg 3 times daily (30 min before initiation of treatment, and over 4-8 hours). For the prevention of delayed emesis are given by 4 mg every 8 hours for 1-2 days and then every 4 mg 2 times a day during the whole course also 5 days after the end of it.

Adults and children over 12 years will administer 16 mg with 1 hour before anesthesia. Children under 12 years should not use this drug.

The maximum nictemeral dose is 32 mg of ondansetron, for patients with moderate and severe impairment of liver function the optimal dose is 8 mg.

Medical action:

The mechanism of action is due to selective blockade of central and peripheral 5HT3 receptors, serotonin. Suppresses the gag reflex, eliminating and preventing vomiting from chemotherapy, radiotherapy and postoperative period. On multiple dosing it slows the peristalsis and the transit through the gut contents.

It is well absorbed from the gastrointestinal tract, bioavailability is about 60% determined by the first-pass metabolism. Peak plasma concentrations of ondansetron is carried over 1.5-1.7 hours. Consumption of food prolongs the half-life by 17%, without affecting the maximum concentration. Plasma protein binding is 70-76%.

The amount removed by the base station (85-90%) is hydrolyzed in the liver with the participation of cytochrome P-450 to derivatives of indole ring and then conjugate with glucuronic acid and sulfuric acid. It is excreted in the urine, about 5% of the preparation is excreted unchanged. Ondansetron pharmacokinetic parameters do not change upon multiple dosing.

In children and also people with liver disease reduces total clearance, in elderly persons the half-life is prolonged and the total clearance increases. In patients with moderate renal impairment (creatinine clearance 15-60 ml / min) systemic clearance is reduced and the ondansetron volume of distribution as well is reduced, resulting in an insignificant increase in half-life of the product.

Precautions:

Ondansetron is not a drug that stimulates gastric or intestinal peristalsis. It should not be used instead of nasogastric suction. The use of ondansetron in patients following abdominal surgery or in patients with chemotherapy-induced nausea and vomiting may mask a progressive ileus and/or gastric distension.

Tablets contain phenylalanine (a component of aspartame). Each 4-mg and 8-mg orally disintegrating tablet contains <0.03 mg phenylalanine.Patients should be instructed not to remove tablets from the blister until just prior to dosing. The tablet should not be pushed through the foil. With dry hands, the blister backing should be peeled completely off the blister. The tablet should be gently removed and immediately placed on the tongue to dissolve and be swallowed with the saliva.

Ondansetron has an increased transit time through the intestine, and therefore patients with signs of subacute intestinal obstruction requiring strict medical supervision after administration of the preparation.

This medicinal product contains lactose, so it can not be taken by patients with rare hereditary intolerance, lactase deficiency or glucose-galactose malabsorption.

The safety of the preparation in pregnant women has not been determined, so its use is not recommended during pregnancy.

In the need during lactation will cease breastfeeding.

Side effects:

In the central nervous system: headache, dizziness, spontaneous movement disorders, seizures convulsions, central nervous system suppression, tingling, weakness, extrapyramidal symptoms, faintness.

Cardiovascular system: hot flushes, arrhythmias, bradycardia or tachycardia, hypotension or hypertension.

From the digestive system: constipation, diarrhea, hiccups, dry mouth, transient increases in aminotransferase activity, hepatic insufficiency.

Allergic reactions: urticaria, bronchospasm occasionally - anaphylactic reactions.

Other: cough, chest pain.

Over dosage:

Symptoms: visual disturbances, constipation, hypotension, vagal episode with transient second degree atrioventricular block.