Description and Composition of Pyrox
Pyrox is an antiulcer drug in the class of proton pump inhibitors. It contains Rabeprazole Sodium as its active pharmaceutical ingredient. It also contains other inactive ingredients called excipients in sufficient quantities. Rabeprazole 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. Because of higher Pka
value of Rabeprazole Sodium it provides
faster onset of action.
Clinical Pharmacology of Pyrox
How does Rabeprazole work?
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+ ÁTPase at the secretory surface of the gastric parietal cell. Because this enzyme it 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 sulfonamide,
Pharmacokinetics of Pyrox
After oral administration of 20 mg Rabeprazole, peak plasma concentrations (Cmax) of Rabeprazole occur over a range 2.0 to 5.0 hours (Tmax). There is no appreciable accumulation when doses of 10 mg to 40 mg are administered every 24 hours; the pharmacokinetics of Rabeprazole is not altered by multiple dosing. The plasma half-life ranges from 1 to 2 hours.
Following oral administration of 20 mg Rabeprazole, it is absorbed and can be detected in plasma by 1 hour. Absolute bioavailability for a 20 mg oral capsule of Rabeprazole is approximately 52%. Rabeprazole is 96.3% bound to human plasma proteins.
Rabeprazole is extensively metabolized. The thioether and sulphone are the primary metabolites measured in human plasma. These metabolites were not observed to have significant antisecretory activity. In vitro studies have demonstrated that Rabeprazole is primarily metabolized in the liver by cytochromes P450 3A (sulphone metabolite) and 2C19 (desmethyl Rabeprazole). 90% of the drug is eliminated in the urine, primarily as thioether carboxylic acid; its glucuronide, and mercapturic acid metabolites.
The anti-secretory effect begins within one hour after oral administration of 20 mg Rabeprazole. The median inhibitory effect of Rabeprazole on 24 hour gastric acidity is 88% of maximal after the first dose. Rabeprazole 20 mg inhibits basal and peptone meal-stimulated acid secretion versus placebo by 86% and 95%, respectively and increases the percent of a 24-hour period that the gastric pH>3 from 10% to 65%. This relatively prolonged pharmacodynamic action compared to the short pharmacokinetic half-life (1-2 hours) reflect the sustained inactivation of the H, K+ATPase,
Geriatric : Reported data from clinical studies in healthy elderly subjects Indicates that AUC values are approximately doubled and Cmax increased by 60% compared to values in a parallel younger control group. There was no evidence of drug accumulation after once dally dosing.
Pediatric : The pharmacokinetics of Rabeprazole in pediatrics has not been studied.
Gender and race: In analysis of body mass and weight, Rabeprazole pharmacokinetics showed no clinically significant differences between male and female volunteers.
Renal disease: No clinically significant difference was observed in the pharmacokinetics of Rabeprazole between healthy volunteers and patients requiring maintenance haemodialysis.
Hepatic disease: Reported data from single dose clinical study indicates that AUC & elimination half lives are doubled in patients with mild to moderate liver cirrhosis as compared to healthy volunteers. No information exists on Rabeprazole disposition in patients with severe hepatic impairment.
Indications and Uses of Pyrox
What is rabeprazole used for?
Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD)
Rabeprazole is indicated for short-term (4 to 8 weeks) treatment in the healing and symptomatic relief of erosive or ulcerative gastroesophageal reflux disease (GERD).
Maintenance of Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD)
Rabeprazole is indicated for maintaining healing and reduction in relapse rates of heartburn symptoms in patients with erosive or ulcerative gastroesophageal reflux disease (GERD Maintenance).
Healing of Duodenal Ulcers
Rabeprazole is indicated for short-term (up to four weeks) treatment in the healing and symptomatic relief of duodenal ulcers. Most patients heal within four weeks. It is highly effective in the presence of H.Pylori.
Treatment of Pathological hypersecretory Conditions, including Zollinger-Ellison Syndrome
Rabeprazole is indicated for the long-term treatment of pathological hypersecretory conditions including Zollinger Ellison Syndrome
Contraindications of Pyrox
When shouldn’t rabeprazole be used?
Rabeprazole is contraindicated in patients with known hypersensitivity to Rabeprazole, substituted benzimidazole or to any component of the formulation.
Symptomatic response to therapy with Rabeprazole does not preclude the presence of gastric malignancy.
Pregnancy & Lactation
There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Since many drugs are excreted in milk, caution should be exercised when Rabeprazole is administered to a nursing mother.
The safety and effectiveness of Rabeprazole in pediatric patients have not been established.
No overall differences in safety or effectiveness were observed between geriatric subjects and younger subjects.
Effects on ability to drive and use machine: It should be taken into account that occasionally dizziness may occur.
Adverse Reactions of Pyrox
What are the side effects of rabeprazole?
Adverse effects with Rabeprazole are mild to moderate intensity and include:
- Skin eruptions
- Headache and dizziness
- Abnormal laboratory findings (increased hepatic enzymes, LDH, blood urea nitrogen) observed with Rabeprazole were similar in incidence and severity with comparator agents and reversible with cessation of therapy.
Inform your doctor in case of any adverse reactions related to drug use.
Drug Interactions with Pyrox
Which drugs Interacts rabeprazole?
Rabeprazole is metabolized by the cytochrome P450 (CYP450) drug metabolizing enzyme system. Rabeprazole does not have clinically significant interactions with other drugs metabolized by the CYP450 system, such as warfarin, theophylline, diazepam and phenytoin.
Rabeprazole produces sustained inhibition of gastric acid secretion. An interaction with compounds which are dependent on gastric pH for absorption like ketoconazole may occur due to the magnitude of acid suppression observed with Rabeprazole. Therefore, patients may need to be monitored when such drugs are taken concomitantly with Rabeprazole.
Co-administration of Rabeprazole and antacids produced no clinically relevant changes in plasma Rabeprazole concentrations.
Overdosage and Treatment of Pyrox
There has been no experience with large overdoses with Rabeprazole. Patients with Zollinger-Ellison syndrome have been treated with up to 120 mg Rabeprazole QD. 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.
Dosage and Administration of Pyrox
What is the dosage of Rabeprazole?
Rabeprazole should be administered before meals.
Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD)
The recommended adult oral dose is 20 mg Rabeprazole to be taken daily for four to eights weeks.
Maintenance of Healing of Erosive or Ulcerative Gastroesophageal Reflux Disease (GERD Maintenance)
The recommended adult oral dose is 20 mg Rabeprazole to be taken daily.
Healing of Duodenal Ulcers:
The recommended adult oral dose is 20 mg Rabeprazole to be taken daily after the morning meal for a period up to four weeks. Most patients with duodenal ulcer heal within four weeks.
Treatment of Pathological hypersecretory Conditions, Including Zollinger-Ellison Syndrome
The dosage of Rabeprazole 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. Doses up to 100 mg QD and 60 mg BID have been administered
No dosage adjustment is necessary in elderly patients, in patients with renal disease or in patients with mild to moderate hepatic impairment. Administration of Rabeprazole to patients with mild to moderate liver impairment resulted in increased exposure and decreased elimination. Due to the lack of clinical data on Rabeprazole in patients with severe hepatic impairment, caution should be exercised in those patients.
Rabeprazole Capsules should be swallowed whole. The Capsules should not be chewed, crushed or split.
Store below 30°C. Protect from light and moisture.
SHELF LIFE: 24 Months
- Use upon doctor’s prescription only.
- Please do not use the drug after the expiry date.
- Please do not use the drug if there are any significant changes in appearance of the capsules.
- Keep out of reach of children.
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