Ond R

Ond R Uses, Dosage, Side Effects, Food Interaction and all others data.

Ondansetron is a selective 5-HT3 receptor antagonist. While its mechanism of action has not been fully characterized, ondansetron is not a dopamine-receptor antagonist. Serotonin receptors of the 5-HT3 type are present both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema. It is not certain whether ondansetron's antiemetic action is mediated centrally, peripherally, or in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine.

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 serotonin 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 , .

Moreover, the effect of ondansetron on the QTc interval was evaluated in a double-blind, randomized, placebo and positive (moxifloxacin) controlled, crossover study in 58 healthy adult men and women . Ondansetron was tested at single doses of 8 mg and 32 mg infused intravenously over 15 minutes . At the highest tested dose of 32 mg, prolongation of the Fridericia-corrected QTc interval (QT/RR0.33=QTcF) was observed from 15 min to 4 h after the start of the 15 min infusion, with a maximum mean (upper limit of 90% CI) difference in QTcF from placebo after baseline-correction of 19.6 (21.5) msec at 20 min . At the lower tested dose of 8 mg, QTc prolongation was observed from 15 min to 1 h after the start of the 15-minute infusion, with a maximum mean (upper limit of 90% CI) difference in QTcF from placebo after baseline-correction of 5.8 (7.8) msec at 15 min . The magnitude of QTc prolongation with ondansetron is expected to be greater if the infusion rate is faster than 15 minutes . The 32 mg intravenous dose of ondansetron must not be administered . No treatment-related effects on the QRS duration or the PR interval were observed at either the 8 or 32 mg dose .

An ECG assessment study has not been performed for orally administered ondansetron . On the basis of pharmacokinetic-pharmacodynamic modelling, an 8 mg oral dose of ondansetron is predicted to cause a mean QTcF increase of 0.7 ms (90% CI -2.1, 3.3) at steady-state, assuming a mean maximal plasma concentration of 24.7 ng/mL (95% CI 21.1, 29.0) . The magnitude of QTc prolongation at the recommended 5 mg/m2 dose in pediatrics has not been studied, but pharmacokinetic-pharmacodynamic modeling predicts a mean increase of 6.6 ms (90% CI 2.8, 10.7) at maximal plasma concentrations .

Rabeprazole Sodium is an antiulcerant drug in the class of Proton Pump Inhibitors. Rabeprazole Sodium is a substituted benzimidazole which suppresses gastric acid secretion by inhibiting the gastric H+/K+-ATPase enzyme at the secretory surface of the gastric parietal cell. It is an enteric coated tablet, because of its coated formulation it is highly stable in stomach and because of higher pKa value of Rabeprazole Sodium it provides faster onset of action. It blocks the final step of gastric acid secretion.

After oral administration of 20 mg, Rabeprazole is absorbed and can be detected in plasma by 1 hour. The effects of food on the absorption of Rabeprazole have not been evaluated. Rabeprazole is 96.3% bound to human plasma proteins. Rabeprazole is primarily metabolized in the liver by Cytochrome P-450 3A (Sulphone metabolite) and 2C19 (Desmethyl Rabeprazole). Following a single 20 mg oral dose of Rabeprazole, approximately 90% of the drug is eliminated in the urine.The remainder of the dose is excreted in the feaces.

Rabeprazole prevents the production of acid in the stomach. It reduces symptoms and prevents injury to the esophagus or stomach in patients with gastroesophageal reflux disease (GERD) or ulcers. Rabeprazole is also useful in conditions that produce too much stomach acid such as Zollinger-Ellison syndrome. Rabeprazole may also be used with antibiotics to get rid of bacteria that are associated with some ulcers. Rabeprazole is a selective and irreversible proton pump inhibitor, suppresses gastric acid secretion by specific inhibition of the H+, K+ -ATPase, which is found at the secretory surface of parietal cells. In doing so, it inhibits the final transport of hydrogen ions (via exchange with potassium ions) into the gastric lumen.

Ond R
Uses
Dosage
Side Effect
Precautions
Interactions
Uses during Pregnancy
Uses during Breastfeeding
Accute Overdose
Food Interaction
Half Life
Volume of Distribution
Clearance
Interaction With other Medicine
Contradiction
Storage

Trade Name	Ond R
Generic	Ondansetron + Rabeprazole
Type	Capsule
Therapeutic Class
Manufacturer	Bestochem Formulations India Ltd
Available Country	India
Last Updated:	September 19, 2023 at 7:00 am

Uses

Ondansetron is used for:

Prevention of nausea and vomiting associated with highly emetogenic cancer chemotherapy
Prevention of nausea and vomiting associated with radiotherapy
Prevention of post operative nausea and vomiting

Short-term treatment in healing and symptomatic relief of duodenal ulcers and erosive or ulcerative Gastroesophageal Reflux Disease (GERD).

Maintaining healing and reducing relapse rates of heartburn symptoms in patients with GERD.

Treatment of daytime and night time heartburn and other symptoms associated with GERD.

Long-term treatment of pathological hypersecretory conditions, including Zollinger Ellison Syndrome.

In combination with Amoxicillin and Clarithromycin to eradicate Helicobacter pylori.

Ond R is also used to associated treatment for these conditions: Chemotherapy-Induced Nausea and Vomiting (CINV), Cholestatic pruritus, Post Operative Nausea and Vomiting (PONV), Uremic Pruritus, Radiation therapy induced nausea and vomiting, Severe Hyperemesis gravidarumDuodenal Ulcer, Gastric Ulcer, Gastro-esophageal Reflux Disease (GERD), Heartburn, Helicobacter Pylori Infection, NSAID Associated Gastric Ulcers, Non-erosive Reflux Esophagitis Disease (NERD), Vomiting, Zollinger-Ellison Syndrome, Erosive reflux esophagitis

How Ond R works

Ondansetron is a selective antagonist of the serotonin receptor subtype, 5-HT3 .

Cytotoxic chemotherapy and radiotherapy are associated with the release of serotonin (5-HT) from enterochromaffin cells of the small intestine, presumably initiating a vomiting reflex through stimulation of 5-HT3 receptors located on vagal afferents . Ondansetron may block the initiation of this reflex. Activation of vagal afferents may also cause a central release of serotonin from the chemoreceptor trigger zone of the area postrema, located on the floor of the fourth ventricle . Thus, the antiemetic effect of ondansetron is probably due to the selective antagonism of 5-HT3 receptors on neurons located in either the peripheral or central nervous systems, or both .

Although the mechanisms of action of ondansetron in treating postoperative nausea and vomiting and cytotoxic induced nausea and vomiting may share similar pathways, the role of ondansetron in opiate-induced emesis has not yet been formally established .

Rabeprazole belongs to a class of antisecretory compounds (substituted benzimidazole proton-pump inhibitors) that do not exhibit anticholinergic or histamine H2-receptor antagonist properties, but suppress gastric acid secretion by inhibiting the gastric H⁺/K⁺ATPase (hydrogen-potassium adenosine triphosphatase) at the secretory surface of the gastric parietal cell. Because this enzyme is regarded as the acid (proton) pump within the parietal cell, rabeprazole has been characterized as a gastric proton-pump inhibitor. Rabeprazole blocks the final step of gastric acid secretion. In gastric parietal cells, rabeprazole is protonated, accumulates, and is transformed to an active sulfenamide. When studied in vitro, rabeprazole is chemically activated at pH 1.2 with a half-life of 78 seconds.

Dosage

Ond R dosage

Prevention of chemotherapy induced nausea & vomiting (CINV):

Adult-

Tablet and oral solution: The recommended adult oral dosage of Ondansetron is 24 mg given as three 8 mg tablets in highly emetogenic chemotherapy. In case of moderately emetogenic chemotherapy the oral dose is one 8 mg Ondansetron tablet or 10 ml of Ondansetron oral solution given twice daily.
Injection: The recommended i.v. dose of Ondansetron is a single 32 mg dose or three 0.15 mg/kg doses. A single 32 mg dose is infused over 15 minutes beginning 30 minutes before the start of emetogenic chemotherapy. Subsequent doses (0.15 mg/kg) are administered 4 and 8 hours after the first dose of Ondansetron.
Suppository: The recommended adult dose is one 16 mg suppository 1-2 hours before treatment. Ondansetron should be continued for upto 5 days after a course of treatment.The recommended dose is one suppository daily.

Pediatric patients-

Tablet and oral solution:for pediatric patients 4 through 11 years of age the dosage is one 4 mg Ondansetron tablet or 5ml of Ondansetron solution should be administered 3 times a day for 1 to 2 days after completion of chemotherapy.
Injection: the dosage in pediatric patients 4 to 18 years of age should three 0.15-mg/kg doses.
Suppository:Not recommended.

Radiotherapy induced nausea and vomiting:

Adult-

Tablet and oral solution: the recommended oral dosage is one 8mg Ondansetron tablet or 10ml of Ondansetron oral solution given 3 times daily.

Post operative nausea & vomiting (PONV):

Adult-

Tablet and oral solution: The recommended dosage is 16 mg given as two 8 mg Ondansetron tablets or 20 ml of Ondansetron oral solution 1hour before induction of anesthesia.
Injection: The recommended I.V. dosage of Ondansetron for adults is 4 mg undiluted administered intravenously in not less than 30 seconds, preferably over 2 to 5 minutes, immediately before induction of anesthesia, or postoperatively if the patient experiences nausea and/or vomiting occurring shortly after surgery. Alternatively, 4 mg undiluted may be administered intramuscularly as a single injection for adults. In patients who do not achieve adequate control of postoperative nausea and vomiting following a single, prophylactic, preinduction, I.V. dose of Ondansetron 4 mg, administration of a second I.V. dose of 4 mg Ondansetron postoperatively does not provide additional control of nausea and vomiting.
Suppository: The recommended adult dose is one 16 mg suppository 1-2 hours before treatment. Ondansetron should be continued for upto 5 days after a course of treatment.The recommended dose is one suppository daily.

Pediatric patients-

Injection: The recommended I.V. dosage of Ondansetron for pediatric patients (2 to 12 years of age) isa single 0.1-mg/kg dose for pediatric patients weighing 40 kg or less, or a single 4 mg dose for pediatric patients weighing more than 40 kg. The rate of administration should not be less than 30 seconds, preferably over 2 to 5 minutes. Little information is available about dosage in pediatric patients younger than 2 years of age.
Suppository: Not recommended.

Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD): 20 mg to be taken once daily for 4 to 8 weeks. For those patients who have not healed after 8 weeks of treatment, an additional 8 week course may be considered.

Maintenance of Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD Maintenance): The recommended adult oral dose is 20 mg once daily.

Treatment of Symptomatic Gastroesophageal Reflux Disease (GERD):The recommended adult oral dose is 20 mg once daily for 4 weeks. If symptoms do not resolve completely after 4 weeks, an additional course of treatment may be considered.

Healing of Duodenal Ulcers:The recommended adult oral dose is 20 mg once daily after the morning meal for a period up to four weeks. Most patients with duodenal ulcer heal within four weeks. A few patients may require additional therapy to achieve healing.

Helicobacter pylori Eradication:To Reduce the Risk of Duodenal Ulcer Recurrence-

Rabeprazole Sodium 20 mg Twice Daily for 7 Days
Amoxicillin 1000 mg Twice Daily for 7 Days
Clarithromycin 500 mg Twice Daily for 7 Days

All three medications should be taken twice daily with the morning and evening meals. It is important that patients comply with the full 7-day regimen.

Treatment of Pathological Hypersecretory Conditions Including Zollinger-Ellison Syndrome: The dosage of Rabeprazole Sodium in patients with pathologic hypersecretory conditions varies with the individual patient. The recommended adult oral starting dose is 60 mg once a day. Doses should be adjusted to individual patient needs and should continue for as long as clinically indicated. Some patients may require divided doses. Doses up to 100 mg QD and 60 mg BID have been administered. Some patients with Zollinger-Ellision syndrome have been treated continuously with Rabeprazole Sodium for up to one year.

Prior to IV infusion, dilute in 50 ml dextrose 5% inj or normal saline.

Side Effects

The most common adverse effects include headache, constipation, diarrhea. In chemotherapy induced nausea and vomiting rash has occurred in approximately 1% of patients receiving Ondansetron. Blurred vision, chest pain with or without ST segment depression, cardiac arrhythmias, hypotension and bradycardia have been rarely reported.

Rabeprazole Sodium may sometimes cause headache, diarrhoea, abdominal pain, vomiting, constipation, dry mouth, increased or decreased appetite, muscle pain, drowsiness and dizziness.

Toxicity

At present, there is little information concerning overdosage with ondansetron . Nevertheless, there have been certain cases of somewhat idiosyncratic adverse effects associated with particular dosages of ondansetron used .

“Sudden blindness” (amaurosis) of 2 to 3 minutes duration plus severe constipation occurred in one patient that was administered 72 mg of ondansetron intravenously as a single dose . Hypotension (and faintness) occurred in another patient that took 48 mg of oral ondansetron . Following infusion of 32 mg over only a 4-minute period, a vasovagal episode with transient second-degree heart block was observed . Neuromuscular abnormalities, autonomic instability, somnolence, and a brief generalized tonic-clonic seizure (which resolved after a dose of benzodiazepine) were observed in a 12-month-old infant who ingested seven or eight 8-mg ondansetron tablets (approximately forty times the recommended 0.1-0.15 mg/kg dose for a pediatric patient) . In all instances, however, the events resolved completely .

The safety of ondansetron for use in human pregnancy has not been established . Ondansetron is not teratogenic in animals . However, as animal studies are not always predictive of human response, the use of ondansetron in pregnancy is not recommended .

Ondansetron is excreted in the milk of lactating rats . It is not known if it is excreted in human milk, however, nursing is not recommended during treatment with ondansetron .

Insufficient information is available to provide dosage recommendations for children 3 years of age or younger .

Precaution

Hypersensitivity reactions have been reported in patients who have exhibited hypersensitivity to other 5-HT3 receptor antagonists. 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.

Administration of Rabeprazole Sodium to patients with mild to moderate liver impairment resulted in increased exposure and decreased elimination. Caution should be exercised in patients with severe hepatic impairment.

Interaction

In patients treated with potent inducers of CYP3A4 (i.e Phenytoin, Carbamazepine or Rifampicin), the oral clearance of Ondansetron was increased and Ondansetron blood concentrations were decreased. Data from small studies indicate that Ondansetron may reduce the analgesic effect of tramadol.

Rabeprazole is metabolized by the Cytochrome P-450 (CYP-450) drug metabolizing enzyme system. Rabeprazole does not have clinically significant interactions with other drugs metabolized by the CYP-450 system,such as Warfarin and Theophylline given as single oral dose, Diazepam as a single intravenous dose, and Phenytoin given as a single intravenous dose. In normal subjects, co-administration of Rabeprazole 20 mg QD resulted in an approximately 30% decrease in the bioavailability of Ketoconazole and increase in the AUC and Cmax for digoxin of 90% and 29% respectively.

Volume of Distribution

The volume of distribution of ondansetron has been recorded as being approximately 160L .

Elimination Route

Ondansetron is absorbed from the gastrointestinal tract and undergoes some limited first-pass metabolism . Mean bioavailability in healthy subjects, following administration of a single 8-mg tablet, was recorded as being approximately 56% to 60% . Bioavailability is also slightly enhanced by the presence of food .

Ondansetron systemic exposure does not increase proportionately to dose . The AUC from a 16-mg tablet was 24% greater than predicted from an 8-mg tablet dose . This may reflect some reduction of first-pass metabolism at higher oral doses .

Absolute bioavailability is approximately 52%.

Half Life

The half-life of ondansetron after either an 8 mg oral dose or intravenous dose was approximately 3-4 hours and could be extended to 6-8 hours in the elderly .

1-2 hours (in plasma)

Clearance

The clearance values determined for ondansetron in various patient age groups were recorded as approximately 0.38 L/h/kg in normal adult volunteers aged 19-40 yrs, 0.32 L/h/kg in normal adult volunteers aged 61-74 yrs, 0.26 L/h/kg in normal adult volunteers aged >=75 yrs .

Elimination Route

Following oral or IV administration, ondansetron is extensively metabolised and excreted in the urine and faeces .

Following a single 20 mg oral dose of 14C-labeled rabeprazole, approximately 90% of the drug was eliminated in the urine, primarily as thioether carboxylic acid; its glucuronide, and mercapturic acid metabolites.

Pregnancy & Breastfeeding use

In pregnancy: Pregnancy category B. Reproduction studies at daily oral dose up to 10 and 30 mg/kg/day have been performed in animals and have revealed no evidence of impaired fertility harm to the fetus due to Ondansetron. There are, however, no adequate and well-controlled studies in pregnant women. So the drug should be used in pregnancy only if clearly needed.

In lactation: Ondansetron excretes in milk of lactating animals. Caution should be exercised when Ondansetron is administered to nursing mother.

Rabeprazole is FDA Pregnancy Category B. No data is available on administration of Rabeprazole to pregnant women. However this drug should be used during pregnancy, only if clearly needed. There are no data on the excretion of Rabeprazole into the breast milk. A decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the benefit of the drug to the mother.

Contraindication

Ondansetron is contraindicated in patients with known hypersensitivity to the drug.

Rabeprazole Sodium is contraindicated in patient with known hypersensitivity to Rabeprazole or to any component in the product.

Special Warning

Pediatric use: Can be given in children 1 month of age and above.

Geriatric use: No dosage adjustment is necessary in the elderly.Dosage adjustment for patients with impaired hepatic function:

Tablet and Oral Solution: The total daily dose of 8 mg should not be exceeded.
Injection: A single maximal dose of 8 mg to be infused over 15 minutes beginning 30 minutes before the start of the emetogenic chemotherapy is recommended.
Suppository: Not recommended

Use in pediatric patients: The safety and effectiveness of Rabeprazole in pediatric patients have not been established.

Acute Overdose

There is no specific antidote for Ondansetron overdose. In addition to the adverse events, hypotension (and faintness) occurred in a patient that took 48 mg of AVONA tablets. In all instances, the events resolved completely.

There has been no experience with large overdoses with Rabeprazole. No specific antidote for Rabeprazole is known. Rabeprazole is extensively protein bound and is not readily dialyzable. In the event of overdosage, treatment should be symptomatic and supportive.