Ranitidine

Ranitidine belongs to the Gastrointestinal Agent acts as a Histamine H₂ Receptor Antagonist.

Ranitidine is a histamine H2 receptor antagonist used to treat duodenal ulcers, Zollinger-Ellison syndrome, gastric ulcers, GERD, and erosive esophagitis.

Ranitidine is Readily absorbed from the gastrointestinal tract (oral); rapidly absorbed (IM)with peak concentrations reached within 1-3 hours after administration and varying greatly among patients. Bioavailability is about 50%-60% due to hepatic metabolism. The volume of distribution is higher than body volume, and measures at approximately 1.4 L/kg. The plasma protein binding of ranitidine is approximately 15%. The major metabolite in the urine is N-oxide, which represents less than 4% of the dose. Other metabolites of ranitidine include S-oxide (1%) and desmethyl ranitidine (1%). Mainly via urine oral route 70%, approximately 35% as unchanged drug and via IV: 93%, 70% as unchanged drug) and in faeces via oral 26% and IV 5%.

Ranitidine shows side effects like Headache, constipation, diarrhoea, nausea, vomiting, stomach pain.

Ranitidine is available in the form of Oral Tablet, Oral capsule, Injectable solution.

Ranitidine is available in India, Canada, Germany, UK, Malaysia, Spain, China, and Australia.

Ranitidine belongs to the Gastrointestinal Agent acts as a Histamine H₂ Receptor Antagonist.

Ranitidine Competitive inhibition of histamine at H₂-receptors of the gastric parietal cells, which inhibits gastric acid secretion, gastric volume, and hydrogen ion concentration are reduced. Does not affect pepsin secretion, pentagastrin-stimulated intrinsic factor secretion, or serum gastrin.

The onset of action of Ranitidine can be observed after an hour of oral or intravenous administration.

The duration of action of Ranitidine lasts for an average duration of 4-6 hours.

Ranitidine is available in the form of Oral Tablet, Oral capsule, Injectable solution.

Ranitidine Tablet and capsule is taken orally, usually in divided dose while injectable solution is given via intramuscular and intravenous route.

Ranitidine is a very effective medicine that is used to reduce the amount of acid produced in the stomach. It is used to treat and prevent stomach acid-related disorders such as heartburn and acid reflux disease.

Ranitidine belongs to the Gastrointestinal Agent acts as a Histamine H₂ Receptor Antagonist.

Ranitidine competitively and reversibly inhibits histamine at the histamine H₂-receptors of the gastric parietal cells, thereby inhibiting gastric acid secretion and gastric volume and reducing hydrogen ion concentration.

Ranitidine is approved for use in the following clinical indications

Adult indication

• Duodenal ulcer
• Gastric ulcer, benign
• Gastroesophageal reflux disease
• Heartburn prevention or relief

Pediatric indication

• Duodenal or gastric ulcer
• Erosive esophagitis
• GI bleed or stress ulcer; prophylaxis
• Gastroesophageal reflux disease
• Heartburn
• Pathological hypersecretory conditions
• Anaphylaxis, adjunct therapy

Adult Dose

• Duodenal ulcer

Oral: Treatment: 150 mg twice daily, or 300 mg once daily after the evening meal or at bedtime; maintenance of healing: 150 mg once daily at bedtime.

IM: 50 mg every 6 to 8 hours.

IV:

Intermittent bolus or infusion: 50 mg every 6 to 8 hours (if increased doses are necessary utilize more frequent administration up to a maximum of 400 mg/day).

Continuous IV infusion: 6.25 mg/hour.

• Gastric ulcer, benign

Oral: 150 mg twice daily; maintenance of healing: 150 mg once daily at bedtime.

• Gastroesophageal reflux disease

Oral: 150 mg twice daily.

• Heartburn prevention or relief

Prevention: 75 to 150 mg 30 to 60 minutes before eating food or drinking beverages that cause heartburn (maximum: 2 doses/day); do not use for more than 14 days.

Relief of symptoms: 75 mg to 150 mg up to twice daily (maximum: 2 doses/day); do not use for more than 14 days.

Pediatric Dose

• Duodenal or gastric ulcer

Treatment:

Infants, Children, and Adolescents ≤16 years:

Oral: 4 to 8 mg/kg/day divided twice daily; maximum daily dose: 300 mg/day.

IV: 2 to 4 mg/kg/day divided every 6 to 8 hours; maximum dose: 50 mg/dose.

Adolescents >16 years:

Oral:

Duodenal ulcer: 150 mg twice daily or 300 mg once daily after the evening meal or at bedtime.

Gastric ulcer: 150 mg twice daily.

IV, IM: 50 mg every 6 to 8 hours.

Maintenance:

Infants, Children, and Adolescents ≤16 years: Oral: 2 to 4 mg/kg/day once daily; maximum daily dose: 150 mg/day.

Adolescents >16 years: Oral: 150 mg once daily at bedtime.

• Erosive esophagitis

Infants, Children, and Adolescents ≤16 years: Oral: 5 to 10 mg/kg/day divided twice daily; maximum dose: 150 mg/dose.

Adolescents >16 years: Oral:

Treatment: 150 mg 4 times daily.

Maintenance: 150 mg twice daily.

• GI bleed or stress ulcer; prophylaxis

Intermittent IV infusion:

Infants: 2 to 6 mg/kg/day divided every 8 hours.

Children and Adolescents: 2 to 6 mg/kg/day divided every 6 hours; maximum daily dose: 300 mg/day.

Continuous IV infusion: Infants, Children, and Adolescents: Initial: 0.15 to 0.5 mg/kg/dose for 1 dose, followed by infusion of 0.08 to 0.2 mg/kg/hour (2 to 5 mg/kg/day).

• Gastroesophageal reflux disease

Infants, Children, and Adolescents: Oral: 5 to 10 mg/kg/day in 2 to 3 divided doses; maximum daily dose: 300 mg/day.

• Heartburn

Prevention: Children ≥12 years and Adolescents: Oral: 75 to 150 mg 30 to 60 minutes before eating food or drinking beverages which cause heartburn; maximum daily dose: 2 doses/day.

Relief of symptoms: Children ≥12 years and Adolescents: Oral: 75 to 150 mg twice daily; maximum daily dose: 2 doses/day.

• Pathological hypersecretory conditions

Adolescents >16 years:

Oral: 150 mg twice daily; adjust dose or frequency as clinically indicated; doses of up to 6 g/day have been used.

Continuous IV infusion: Initial: 1 mg/kg/hour; measure gastric acid output at 4 hours, if >10 mEq/hour or if patient is symptomatic, increase dose in increments of 0.5 mg/kg/hour; doses of up to 2.5 mg/kg/hour (or 220 mg/hour) have been used.

• Anaphylaxis, adjunct therapy

Infants, Children, and Adolescents: IV: 1 mg/kg/dose; maximum dose: 50 mg/dose.

Ranitidine is available in various strengths as 150 mg; 300 mg; 75 mg; 15 mg/mL; 25 mg/mL; 1 mg/mL; 25 mg.

Ranitidine is available in the form of Oral Tablet, Oral capsule, Injectable solution.

• Dosage Adjustment in Kidney Patient

CrCl ≥50 mL/minute: No dosage adjustment necessary.

CrCl <50 mL/minute:

Oral: 150 mg every 24 hours; adjust dose cautiously if needed (frequency of dosing may be increased to every 12 hours or further with caution).

IV: 50 mg every 18 to 24 hours; adjust dose cautiously if needed.

Ranitidine is contraindicated in patients with

• Allergy

This medicine is not recommended for use in patients with a known allergy to ranitidine or any other inactive ingredients present along with it.

• Porphyria

This medicine is not recommended for use in patients with porphyria, a disorder that results from a buildup of porphyrin in the body.

• Pneumonia

Use of this medicine may increase the risk of developing pneumonia. Symptoms like chest pain. fever. difficulty in breathing and presence of green or yellow mucus with a cough is to be reported to the doctor on priority.

• Chronic heartburn

If you have a chronic heartburn (more than 3 months) or your heartburn continues or worsens, consult your doctor immediately since this may be a sign of a more serious condition. Appropriate dose adjustments or replacement with a suitable alternative may be required in such cases based on the clinical condition.

• Vitamin B12 deficiency

This medicine can interfere with the absorption of Vitamin B12 upon prolonged usage. Your doctor may prescribe appropriate supplementation or may suggest appropriate changes in your diet based on your clinical condition.

• Kidney disease

This medicine should be used with caution in patients with kidney diseases due to the increased risk of severe adverse effects. Appropriate dose adjustments and close monitoring of renal function may be required based on the clinical condition.

• Phenylketonuria

Some formulations of this medicine may contain phenylalanine. Such formulations should be used with extreme caution in patients with Phenylketonuria who must restrict their intake of phenylalanine. Replacement with a suitable alternative may be required based on the clinical condition.

• Use of nicotine

Use of nicotine is not recommended during treatment with this medicine due to the increased risk of severe adverse effects.

Ranitidine is not recommended for use in breastfeeding women unless necessary. All the risks and benefits should be considered before taking Ranitidine.

Ranitidine is not recommended for use in pregnant women unless necessary. All the risks and benefits should be considered before taking Ranitidine.

• Common

Asystole, atrioventricular block, bradycardia (with rapid IV administration), tachycardia, vasculitis, ventricular premature contractions, Agitation, confusion, dizziness, depression, drowsiness, hallucination, headache, insomnia, involuntary motor activity, malaise, vertigo, Alopecia, erythema multiforme, injection site pruritus (transient), skin rash, Acute porphyria, increased serum prolactin, Abdominal distress, abdominal pain, constipation, diarrhea, nausea, necrotizing enterocolitis (very low weight neonates, pancreatitis, vomiting, Agranulocytosis, aplastic anemia, granulocytopenia, hemolytic anemia (immune; acquired), leukopenia, pancytopenia, thrombocytopenia, Cholestatic hepatitis, hepatic failure, hepatitis, jaundice, Anaphylaxis, angioedema, hypersensitivity reaction (eg, bronchospasm, eosinophilia, fever), Burning sensation at injection site (transient), pain at injection site (transient), Arthralgia, myalgia, Blurred vision, Acute interstitial nephritis, increased serum creatinine, Pneumonia.

• Acalabrutinib

Histamine H2 Receptor Antagonists may decrease the serum concentration of Acalabrutinib. Management: Give acalabrutinib capsules 2 hours before a histamine H2 receptor antagonist (H2RA). No action is required if acalabrutinib tablets are coadministered with H2RAs.

• Atazanavir

Histamine H2 Receptor Antagonists may decrease the serum concentration of Atazanavir. Management: Specific dose limitations and administration guidelines exist; consult full interaction monograph or atazanavir prescribing information.

• Infigratinib

Histamine H2 Receptor Antagonists may decrease serum concentrations of the active metabolite(s) of Infigratinib. Histamine H2 Receptor Antagonists may decrease the serum concentration of Infigratinib. Management: Avoid coadministration of infigratinib with histamine receptor antagonists (H2RAs) or other gastric acid-lowering agents. If H2RAs cannot be avoided, administer infigratinib 2 hours before or 10 hours after administration of H2RAs.

• Itraconazole

Histamine H2 Receptor Antagonists may increase the serum concentration of Itraconazole. Histamine H2 Receptor Antagonists may decrease the serum concentration of Itraconazole. Management: Administer Sporanox brand itraconazole at least 2 hours before or 2 hours after administration of any histamine H2 receptor antagonists (H2RAs). Exposure to Tolsura brand itraconazole may be increased by H2RAs; consider itraconazole dose reduction.

• Ketoconazole (Systemic)

Histamine H2 Receptor Antagonists may decrease the serum concentration of Ketoconazole (Systemic). Management: Administer ketoconazole with an acidic beverage (eg, non-diet cola) and monitor for reduced efficacy if concomitant use with a H2RA is required. Increases in ketoconazole dose may be required.

• Ledipasvir

Histamine H2 Receptor Antagonists may decrease the serum concentration of Ledipasvir. Management: Administer H2 receptor antagonist doses less than or comparable to famotidine 40 mg twice daily simultaneously or 12 hours prior to ledipasvir. The effect of administering H2 receptor antagonists at other time intervals is unknown and not recommended.

• Levoketoconazole

Histamine H2 Receptor Antagonists may decrease the absorption of Levoketoconazole.

• Lomitapide

Ranitidine may increase the serum concentration of Lomitapide. Management: Patients taking lomitapide 10 mg/day or more should decrease the lomitapide dose by half with concurrent ranitidine; the lomitapide dose may then be increased to a max adult dose of 30 mg/day (patients on lomitapide 5 mg/day may continue that dose).

• Lumacaftor and Ivacaftor

May decrease the serum concentration of Ranitidine Lumacaftor and Ivacaftor may increase the serum concentration of Ranitidine.

• Multivitamins/Minerals (with ADEK, Folate, Iron)

Histamine H2 Receptor Antagonists may decrease the serum concentration of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, the absorption of iron may be impaired by H2-antagonists.

• Nelfinavir

Histamine H2 Receptor Antagonists may decrease serum concentrations of the active metabolite(s) of Nelfinavir. Histamine H2 Receptor Antagonists may decrease the serum concentration of Nelfinavir. Concentrations of the active M8 metabolite may also be reduced.

The common side effects of Ranitidine include the following

Common side effects

• Headache, constipation, diarrhea, nausea, vomiting, stomach pain.

Rare side effects

• Dizziness, Diarrhea, Mental confusion, Gynecomastia, Difficulty in breathing.

• Pregnancy

Pregnancy Category B

Ranitidine is not recommended for use in pregnant women unless necessary. All the risks and benefits should be considered before taking this medicine.

• Nursing Mothers

Ranitidine is not recommended for use in breastfeeding women unless necessary. All the risks and benefits should be considered before taking this medicine.

• Pediatric Use

This medicine should be used with extreme caution in children due to the increased risk of severe adverse effects. All the risks and benefits should be considered before using this medicine.

• Geriatric Use

Information not available.

Symptoms: Abnormalities of gait, hypotension; transient adverse effects similar to those encountered in normal clinical experience.

Management: Symptomatic and supportive treatment.

Pharmacodynamic

Ranitidine decreases the secretion of gastric acid stimulated by food and drugs. It also reduces the secretion of gastric acid in hypersecretory conditions such as Zollinger-Ellison syndrome.

Pharmacokinetics

• Absorption

Ranitidine is Readily absorbed from the gastrointestinal tract (oral); rapidly absorbed (IM)with peak concentrations reached within 1-3 hours after administration and varying greatly among patients. Bioavailability is about 50%-60% due to hepatic metabolism.

• Distribution

The volume of distribution is higher than body volume, and measures at approximately 1.4 L/kg. The plasma protein binding of ranitidine is approximately 15%.

• Metabolism and Excretion

The major metabolite in the urine is N-oxide, which represents less than 4% of the dose. Other metabolites of ranitidine include S-oxide (1%) and desmethyl ranitidine (1%). Mainly via urine oral route 70%, approximately 35% as unchanged drug and via IV: 93%, 70% as unchanged drug) and in faeces via oral 26% and IV 5%.

• https://www.drugs.com/ranitidine.html
• https://go.drugbank.com/drugs/DB00863
• https://medlineplus.gov/druginfo/meds/a601106.html#:~:text=Ranitidine is used to treat,such as Zollinger-Ellison syndrome.
• https://reference.medscape.com/drug/zantac-ranitidine-342003
• https://www.uptodate.com/contents/ranitidine-united-states-withdrawn-from-market-drug-information?search=ranitidine&source=panel_search_result&selectedTitle=1~78&usage_type=panel&kp_tab=drug_general&display_rank=1
• https://www.mims.com/philippines/drug/info/ranitidine?mtype=generic
• https://www.practo.com/medicine-info/ranitidine-242-api
• https://www.rxlist.com/zantac-360-drug.htm#medguide