Ondansetron , marketed under the brand name Zofran , is a drug used to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy, or surgery. It is also useful in gastroenteritis. It has little effect on vomiting caused by motion sickness. Can be given by mouth, or by injection to the muscle or to the blood vessels.
Common side effects include diarrhea, constipation, headache, drowsiness, and itching. Serious side effects include prolonged QT and severe allergic reactions. It seems safe during pregnancy but has not been well studied in this group. This is a 5-HT serotonin receptor antagonist 3 . It has no effect on dopamine receptors or muscarinic receptors.
Ondansetron was first used medically in 1990. It is a List of Essential Medicines of the World Health Organization, the most effective and safe medicines needed in the health system. It is available as a generic drug. The cost of injecting syringes in developing countries is about US $ 0.10 to US $ 0.76 per dose. In the United States it costs about US $ 1.37 per tablet.
Video Ondansetron
Medical use
Despite an effective antiemetic agent, the high cost of ondansetron brand names initially limited its use to control postoperative nausea and vomiting and chemo-induced nausea and vomiting.
Cancer treatment
The 5-HT receptor antagonist 3 is the main drug used to treat and prevent chemotherapy-induced nausea and vomiting and radiotherapy-induced nausea and vomiting.
Postoperation
A number of drugs including ondansetron appear to be effective in controlling postoperative nausea and vomiting. It's more effective than metoclopramide, and less sedative than cyclizine or droperidol.
Pregnancy
Ondansetron is used off-label to treat morning sickness and hyperemesis gravidarum of pregnancy. This is usually used after other drug trials have failed.
Animal reproduction studies have not shown any evidence of harm to infants or fertility problems with high daily doses of ondansetron. A study of more than 600,000 pregnancies in Denmark found that ondansetron during pregnancy was not associated with an increased risk of spontaneous abortion, stillbirth, major birth defects, premature birth, low birth weight, or small for gestational age. Other studies have concluded that there is an increase in major congenital malformations due to increased heart problems in infants.
Ondansetron is in the B pregnancy category in the US. It is not known whether ondansetron is excreted in breast milk.
Cyclic vomiting syndrome
Ondansetron is one of the few antiemetic agents used during the vomiting phase of cyclic vomiting syndrome.
Gastroenteritis
Experiments in emergency department settings support the use of ondansetron to reduce vomiting associated with gastroenteritis and dehydration. A retrospective review finds it used generally for this purpose, which is managed in over 58% of cases. Its use reduces hospital admissions, but is also associated with higher returns to the emergency department. In addition, people who initially received ondansetron were more likely to be treated on return visits than people who did not receive the drug. However, this effect may be due to agents being used more frequently in people who come with more severe disease. Its use is not found to cover serious diagnoses.
Maps Ondansetron
Custom population
Children
Ondansetron is rarely studied in people under 4 years of age. Thus, small data is available to guide dose recommendations.
Elderly
No need to adjust the dosage for people under 75 years. The use of ondansetron has not been studied in people older than 75 years, and it is not known whether the dose should be adjusted for this group.
Bad liver function
The maximum recommended dose for people with severe liver dysfunction is 8 mg/day. In these people, ondansetron is cleansed from the body in half to one-third of the level as in healthy people. The concentration of ondansetron in body tissues as compared to plasma is also higher than in healthy people.
Adverse effects
Headache is the most common side effect. A review of the use for postoperative nausea and vomiting found that for every 36 people treated, a person will experience headaches, which can be severe.
Constipation, diarrhea, dizziness, and headache are other commonly reported side effects. It is broken down by the liver cytochrome P450 system and has little effect on the metabolism of other drugs that are broken down by this system. Anecdotally, ototoxicity has also been reported if injected too quickly.
QT extension
The use of ondansetron has been associated with an extension of the QT interval, which can lead to a fatal heart rhythm known as torsades de pointes . Although this can happen to any person with any formulation, the risks are most prominent in the form of injectable (intravenous) drugs and increase with the dose. The risk is also higher in people taking other drugs that prolong the QT interval, as well as in people with long-standing QT syndrome, congestive heart failure, and/or bradyarrhythmias. Thus, single dose ondansetron should not exceed 16 mg at a time. (Recommendation of oral dose remains intact, including a single oral dose of 24 mg recommendation as indicated.) Electrolyte imbalances should be corrected before injecting ondsetron use. People are warned to seek immediate medical care if symptoms such as irregular heartbeat/palpitations, shortness of breath, dizziness, or fainting occur while taking ondansetron.
Overdose
No special treatments are available for overdose ondansetron; people are managed with supportive steps. The ondansetron antidote is unknown.
Pharmacodynamics
Ondansetron is a highly specific and selective serotonin 5-HT 3 receptor antagonist, with a low affinity for dopamine receptors. The 5-HT 3 receptor is present both peripherally at the vagal nerve terminals and centrally in the chemoreceptor trigger zone of the regional postrema. Serotonin is released by enterochromaffin cells from the small intestine in response to chemotherapy agents and may stimulate afferent vagal (via 5-HT receptor 3 ) to initiate vomiting reflex. It is thought that the ondansetron antiemetic action is mediated largely through the afferent vagal antagonism with a small contribution from central receptor antagonism.
History
Ondansetron (marketed under the brand name Zofran) was developed in the mid-1980s by GlaxoSmithKline in London. It granted US patent protection in September 1987, received a patent of use in June 1988, and was approved by the US FDA in January 1991. It was granted another divisional patent in November 1996. Finally, due to GlaxoSmithKline's research on pediatric use, the Protective ondansetron patent extended until December 2006 In the last year of this patent (2006), Zofran has become the 20th highest brand-name drug in the United States, with sales of US $ 1.3 billion in the first nine months of 2006 (80% of US). The first generic version was approved by the US FDA in December 2006, with marketing approval granted to Teva Pharmaceuticals USA and SICOR Pharmaceuticals.
Society and culture
Publication bias
In 1997, ondansetron was the subject of a meta-analysis case study published in the British Medical Journal . The researchers examined 84 trials, with 11,980 receiving ondansetron, published between 1991 and September 1996. Ondansetron 4 mg versus an intravenous placebo was investigated in 16 reports and three further reports were doubled six times. The amount needed to treat (NNT) to prevent vomiting within 24 hours was 9.5, with a 95% confidence interval from 6.9 to 15, in 16 unclassified reports. In the three duplicated reports, NNT was significantly lower at 3.9 (3.3 to 4.8). When all 25 reports were combined, the real NNT increased to 4.9 (4.4 to 5.6). The inclusion of duplicate reports leads to 23% overestimation of ondansetron antiemetic efficacy.
In addition, the authors found the secret duplication of ondansetron reports not easy to detect, due to lack of cross-references between papers, and reports containing duplicate findings cited in eight drug reviews. Their analysis was the subject of an editorial in the Journal of the American Medical Association in 1999.
Availability
Ondansetron is a generic drug and is available in many countries with many brand names.
Research
Psychiatric disorders
A randomized double-blind controlled trial in 2006 showed that ondansetron may have value in the treatment of schizophrenia, in addition to haloperidol. The study found a combination to significantly improve the symptoms of negative schizophrenia, and people taking both drugs experienced fewer adverse effects commonly associated with haloperidol. Previously, smaller, open-label trials have found a useful ondansetron in treating tardive tardive-induced antipsychotics in people with schizophrenia, and research patients also showed significant improvements in symptoms of the disease.
Initial studies have also examined ondansetron as a possible treatment for psychosis due to advanced Parkinson's disease. The benefits are clear although no significant antagonistic properties of dopamine receptors or 5-HT receptors 2A raise an interesting question about the etiology of psychosis.
Use of substance
There is tentative evidence that may be useful in reducing the desired alcohol effect. There is also some evidence while in those who are addicted to stimulants.
Postanesthetic shivers
Two small placebo-controlled trials have been conducted to assess the effectiveness of ondansetron for postanestic shivering, a common occurrence after surgery. Ondansetron was found to be as effective as pethidine (meperidine, Demerol) when administered as a single intravenous dose prior to anesthesia.
References
External links
- US. National Drug Library: Drug Information Portal - Ondansetron
Source of the article : Wikipedia
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