R-Ondansetron (R-Ondansetronum)

Pharmacodynamics Pharmacokinetics Indications Carefully Contraindications Dosing and Administration Side effects
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Clinical and pharmacological group: & nbsp

Antiemetic drugs

Included in the formulation
АТХ:

A.04.A.A.01   Ondansetron

Pharmacodynamics:

Selective blockade of serotonin 5-HT3receptors of neurons on the periphery (end of the vagus nerve in the intestine) and in the central nervous system (the bottom of the IV ventricle), regulating the implementation of emetic reflexes.

Pharmacokinetics:

Relationship with plasma proteins 70-76%. Vd after intravenous administration of 8 mg ondansetron 2.28 l / kg. Biotransformation in the liver with the participation of cytochrome P450 isoenzymes 1A2, 2D6, 3A4. Half-life is 5.7 hours, in children 2.5-3 hours, in adults with moderate hepatic insufficiency - 11.6 hours, with severe violations of the liver - 20.6 hours. Systemic clearance after intravenous administration is 0.15 mg / kg, for persons 9-40 years - 0.381 l / h × kg, for persons 61-74 years - 0.319 l / h × kg, for persons older than 75 years - 0.262 l / h × kg. Elimination mainly with feces, kidneys - less than 5% unchanged.

Indications:

- nausea and vomiting caused by cytostatic radiation therapy or chemotherapy;

- nausea and vomiting in the postoperative period;

- symptomatic treatment of alcohol withdrawal syndrome of mild and moderate severity.

ICD-10

XVIII.R10-R19.R11   Nausea and vomiting

Contraindications:

- individual intolerance;

- pregnancy.

Carefully:

Children's age (experience in children under 1 year is not enough).

Inhibition of GI motility, signs of intestinal obstruction (patients should be under special supervision).

Pregnancy and lactation:

FDA exposure category F. Ondansetron is contraindicated in pregnancy. If necessary, use during lactation should stop breastfeeding.

Dosing and Administration:

Nausea and vomiting caused by cytostatic radiation therapy or chemotherapy: 8-32 mg per day. With a moderate expression of the emetogenic effect of chemo- or radiotherapy, 8 mg is administered intravenously slowly or intramuscularly intramuscularly just before the start of treatment. If the emetogenic effect of chemotherapy is significant, 8 mg is injected intravenously slowly before the start of chemotherapy, then either repeated at the same dose every 2-4 hours, or injected continuously intravenously at a rate of 1 mg / h for 24 hours, or administered intravenously drip for at least 15 minutes before starting chemotherapy at a dose of 16-32 mg, diluting in 50-100 ml of the appropriate infusion solution.

Nausea and vomiting in the postoperative period: during the initial general anesthesia 4 mg. When nausea and vomiting occur, the drug is administered intravenously or intramuscularly at the same dose.

Side effects:

Local reactions: hyperemia, pain, burning at the injection site.

Pain in the chest, in some cases with depression of the segment ST, arrhythmia, bradycardia, lowering blood pressure.

Nervous system: headache (9-27%), dizziness (4-7%), drowsiness, paresthesia, fatigue, fatigue and weakness, spontaneous movement disorders and convulsions.

Hiccups, dry mouth, abdominal pain, constipation (6-9%) or diarrhea (3-7%), increased activity of hepatic transaminases in the blood serum (1-2%).

Blood flushes to the skin of the face, a feeling of heat (2-8%), temporary disturbance of visual acuity, hypokalemia, hypercreatininaemia.

Rarely: urticaria, bronchospasm, anaphylaxis, angioedema.

Overdose:

In case of an overdose, there is a decrease in blood pressure, weakness, constipation, amaurosis, transient AV blockade of degree II. Treatment is symptomatic.

Interaction:

Allopurinol, antidepressants (MAO inhibitors), valproic acid and its salts, verapamil, diltiazem, disulfiram, isoniazid, ketoconazole, lovastatin, macrolides, metronidazole, omeprazole, propranolol, fluconazole, fluoroquinolones, quinidine, quinine, chloramphenicol, cimetidine, estrogen-containing oral contraceptives (inhibitors of cytochrome P450 isoenzyme 2D6, 3A inhibitors) - increased toxicity of ondansetron.

Barbiturates, glutethimide, griseofulvin, dinitrogen oxide, carbamazepine, carisoprodol, papaverine, rifampicin, tolbutamide, phenylbutazone, phenytoin and, possibly, other hydantoins (inducers of cytochrome P450 2D6, 3A isoenzymes) - a decrease in ondansetron efficiency.

Dexamethasone with a single intravenous dose of 20 mg before the start of chemotherapy - increasing the effectiveness of ondansetron.

Special instructions:

When used in patients with moderate and severe impairment, liver function is not recommended to exceed the dose of 8 mg per day.

Instructions
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