Usage
Roxatidine is prescribed for the treatment of duodenal ulcers, benign gastric ulcers, Zollinger-Ellison syndrome, gastroesophageal reflux disease (GERD), and gastritis. It is also used as premedication before anesthesia. It is classified as a H2-receptor antagonist.
Roxatidine works by competitively blocking histamine at H2 receptors in the parietal cells of the stomach, thereby reducing basal and stimulated gastric acid secretion.
Alternate Names
Roxatidine acetate hydrochloride is the chemical name. Brand names include Altat, Rotane, Zorpex, and others, which may vary depending on the region.
How It Works
Pharmacodynamics: Roxatidine competitively inhibits the binding of histamine to H2 receptors on gastric parietal cells. This action leads to a reduction in both basal and stimulated gastric acid secretion, including that stimulated by gastrin and acetylcholine. Total pepsin output is also reduced in a dose-dependent manner. Roxatidine has an independent mucosal protective effect. It does not impact drug-metabolizing enzymes in the liver or exhibit antiandrogenic effects.
Pharmacokinetics:
- Absorption: Roxatidine is rapidly and almost completely absorbed from the gastrointestinal tract after oral administration. Peak plasma concentrations are reached within 1-3 hours. Food or antacids do not affect the absorption of Roxatidine.
- Distribution: It enters breast milk in small amounts.
- Metabolism: Roxatidine is metabolized in the liver, small intestine, and serum, primarily by hydrolysis to its desacetyl metabolite.
- Elimination: It is primarily excreted in the urine (about 90% as roxatidine and metabolites) with an elimination half-life of approximately 6 hours.
Mode of Action: Roxatidine works by competitively blocking H2 receptors on parietal cells, thus preventing histamine, gastrin, and acetylcholine from stimulating acid secretion.
Receptor Binding: It binds specifically to the H2 receptor subtype.
Elimination Pathways: Roxatidine is primarily eliminated through renal excretion, with a small portion undergoing hepatic metabolism.
Dosage
Standard Dosage
Adults:
- Duodenal Ulcer/Benign Gastric Ulcer/Reflux Esophagitis: 150 mg at bedtime or 75 mg twice daily for 4-6 weeks. Maintenance: 75 mg at bedtime.
- Zollinger-Ellison Syndrome: 75 mg twice daily.
- GERD: 75 mg twice daily or 150 mg at bedtime for 6-8 weeks.
- Gastritis: 75 mg once daily in the evening.
- Premedication before anesthesia: 150 mg the night before surgery or 75 mg the evening before surgery and 75 mg 2 hours before induction of anesthesia.
Children:
- Gastric Ulcer/Duodenal Ulcer/Reflux Esophagitis/Zollinger-Ellison syndrome: Under 30kg: 37.5 mg twice a day. Over 30 kg: 75 mg twice a day.
- Gastritis: Under 30 kg: 37.5 mg once a day. Over 30kg: 75 mg once a day.
- Premedication before anesthesia: Under 30 kg: 37.5 mg twice (the night before surgery and 2 hours pre-op). Over 30kg: 75 mg twice (the night before surgery and 2 hours pre-op). Alternatively, under 30 kg: 37.5 mg and over 30 kg: 75 mg once the night before surgery.
Pediatric dosing information is available mostly from resources discussing Japanese medical guidelines and should be verified for local use. It is generally not recommended for children under 14 in other regions.
Special Cases:
- Elderly Patients: Dose adjustment based on renal function is necessary.
- Patients with Renal Impairment: CrCl <20 mL/min: 75 mg every 2 days; CrCl 20-50 mL/min: 75 mg at bedtime. Further adjustments may be needed for other levels of renal impairment.
- Patients with Hepatic Dysfunction: Dose reduction may be required.
- Patients with Comorbid Conditions: Consider individual patient factors.
Clinical Use Cases Dosages are as described in standard use cases and should be adapted depending on patient factors and clinical considerations. Direct application of these dosages for intubation, surgical procedures, mechanical ventilation, or ICU and emergency use are not available in the provided sources.
Dosage Adjustments
Dose modifications are necessary based on renal function, hepatic function, age, and other comorbid conditions. Consider genetic polymorphisms affecting drug metabolism.
Side Effects
Common Side Effects
Headache, gastrointestinal disturbances (e.g., diarrhea, constipation, nausea, vomiting), dizziness, sleep disturbances, restlessness.
Rare but Serious Side Effects
Gynecomastia, alopecia, blood dyscrasias, pancreatitis, hypersensitivity reactions (rash, itching), changes in pulse rate, transient impairment of sexual drive, elevated liver enzymes.
Long-Term Effects
Limited information available on long-term effects. Monitor for potential chronic complications with extended use.
Adverse Drug Reactions (ADR)
Hypersensitivity reactions requiring urgent medical attention.
Contraindications
Hypersensitivity to roxatidine, lactation, porphyria, anuria, absence of urination, and malignant gastric ulcers.
Drug Interactions
Roxatidine may interact with protease inhibitors, antacids, and several other drugs. There is no data suggesting interactions with antihypertensives or benzodiazepines.
Specifically it can lower efficacy of the following: Atazanavir, Bifonazole, Cefdinir, Delavirdine, Erlotinib, Fosamprenavir, Itraconazole, Ketoconazole, Ledipasvir, Pazopanib, Perflubutane, Posaconazole, Rilpivirine, Sofosbuvir, Voriconazole.
Specifically it can lower the efficacy of diagnostic test using Benzylpenicilloyl polylysine.
Specifically it can lower the serum level of Raltegravir.
Theophylline’s pharmacokinetics are generally not altered by Roxatidine.
Pregnancy and Breastfeeding
Roxatidine’s pregnancy safety category is not clearly classified. Use with caution during pregnancy and avoid if possible, especially after week 20. It is contraindicated during lactation.
Drug Profile Summary
- Mechanism of Action: H2-receptor antagonist, reducing gastric acid secretion.
- Side Effects: Headache, GI disturbances, dizziness, rare but serious effects like blood dyscrasias and pancreatitis.
- Contraindications: Hypersensitivity, lactation, porphyria, anuria.
- Drug Interactions: Protease inhibitors.
- Pregnancy & Breastfeeding: Use with caution in pregnancy, contraindicated during breastfeeding.
- Dosage: See detailed dosage section above.
- Monitoring Parameters: Liver function tests, renal function tests, complete blood count.
Popular Combinations
Specific information on popular drug combinations not available. Antacid combinations may be used to provide symptomatic relief in addition to acid reduction.
Precautions
- General Precautions: Evaluate renal and hepatic function, rule out gastric malignancy, and assess for hypersensitivity.
- Specific Populations: See special cases in the dosage section.
- Lifestyle Considerations: Smoking may be associated with ulcer relapse.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Roxatidine?
A: Please refer to the comprehensive dosage section above for details covering adult, pediatric, and special populations.
Q2: How does Roxatidine differ from other H2 blockers?
A: While all H2 blockers share a similar mechanism of action, they differ in their potency, pharmacokinetic profile, and potential for drug interactions. Roxatidine has fewer drug interactions than cimetidine.
Q3: What are the most common side effects of Roxatidine?
A: Headache and gastrointestinal disturbances are the most commonly reported side effects.
Q4: Can Roxatidine be used during pregnancy?
A: Roxatidine should be used with caution during pregnancy, especially after 20 weeks, and only if clearly needed.
Q5: Is Roxatidine safe for patients with kidney disease?
A: Dosage adjustments are necessary for patients with renal impairment. See the dosage section for details.
Q6: How long does it take for Roxatidine to work?
A: Peak plasma concentrations are achieved within 1-3 hours after oral administration.
Q7: Can Roxatidine be used to treat stress ulcers?
A: Although this is not a standard indication described in the provided resources, H2 blockers have been used for stress ulcer prophylaxis. It is recommended to check recent guidelines and specialized literature for the current best practices.
Q8: Can Roxatidine be crushed or chewed?
A: Roxatidine tablets should generally be swallowed whole and not crushed or chewed, unless specifically indicated otherwise by the drug formulation.
Q9: Does Roxatidine interact with alcohol?
A: Information on interaction with alcohol is limited, but it is generally advised to be cautious when using Roxatidine with other CNS depressants.
Q10: What should I do if I miss a dose of Roxatidine?
A: Take the missed dose as soon as you remember, unless it is almost time for the next dose. Do not double the dose to catch up.
