Ranitidine Hydrochloride

Ranitidine is a histamine-2 (H2) receptor antagonist that reduces stomach acid production. It is used to treat and prevent ulcers, GERD, and hypersecretory conditions like Zollinger-Ellison syndrome.

When Ranitidine was clinically available, dosages were highly individualized based on the condition being treated and the patient's response. The following represent standard historical dosing ranges:

• Active Duodenal Ulcer: The typical adult dosage was 150 mg twice daily (BID) or 300 mg once daily after the evening meal or at bedtime. Most patients healed within 4 weeks.
• Maintenance of Healed Duodenal Ulcer: A reduced dose of 150 mg at bedtime was standard for long-term maintenance.
• Benign Gastric Ulcer: The recommended dose was 150 mg twice daily.
• GERD/Heartburn: For the relief of heartburn, 150 mg twice daily was common. For the treatment of erosive esophagitis, the dose could be increased to 150 mg four times daily under strict medical supervision.
• Pathological Hypersecretory Conditions: Dosing often started at 150 mg twice daily but could be titrated significantly higher. In some severe cases of Zollinger-Ellison syndrome, doses up to 6 grams per day were administered.

Ranitidine was approved for use in pediatric patients ranging from 1 month to 16 years of age for certain indications.

• Duodenal and Gastric Ulcers: The recommended oral dose for treatment was 2 to 4 mg/kg twice daily, up to a maximum of 300 mg per day.
• GERD and Erosive Esophagitis: Dosing typically ranged from 5 to 10 mg/kg per day, usually divided into two doses.
• Safety Note: The safety and effectiveness of Ranitidine in neonates (infants under 1 month of age) have not been established.

Renal Impairment

Because Ranitidine is primarily excreted by the kidneys, dosage adjustments are critical for patients with compromised renal function. For patients with a creatinine clearance (CrCl) of less than 50 mL/min, the recommended dose was typically 150 mg once every 24 hours. If the patient's condition required it, the frequency could be increased to every 12 hours with extreme caution. Hemodialysis reduces circulating levels of ranitidine; therefore, the scheduled dose should ideally be administered after the completion of dialysis.

Hepatic Impairment

Since Ranitidine is metabolized in the liver, patients with severe hepatic dysfunction should be monitored closely. While specific dose-reduction formulas were not always mandated for mild liver disease, healthcare providers often exercised caution in patients with cirrhosis or hepatitis.

Elderly Patients

Clinical trials have shown that the elimination half-life of Ranitidine is prolonged in elderly volunteers (average 3-4 hours) due to the natural decline in renal function associated with aging. Healthcare providers typically started elderly patients at the lower end of the dosing range to minimize the risk of central nervous system side effects, such as confusion or agitation.

For optimal efficacy, Ranitidine should be taken exactly as prescribed by a healthcare provider.

• Timing: For ulcer treatment, it is often taken once daily at bedtime or twice daily (morning and evening). For heartburn prevention, it is typically taken 30 to 60 minutes before consuming food or beverages that trigger symptoms.
• Food: It can be taken with or without food.
• Administration: Tablets and capsules should be swallowed whole with a full glass of water. Effervescent tablets (if available) must be dissolved in water before drinking.
• Storage: Store at room temperature (15°C to 30°C or 59°F to 86°F) in a dry place away from light.

If a dose is missed, it should be taken as soon as the patient remembers. However, if it is almost time for the next scheduled dose, the missed dose should be skipped to avoid doubling the dose. Consistently missing doses may reduce the effectiveness of the treatment and delay the healing of ulcers.

Ranitidine has a relatively high therapeutic index, and reports of severe toxicity from acute overdose are rare. Symptoms of overdose may include muscular tremor, vomiting, rapid breathing (tachypnea), and incoordination (ataxia). In the event of a suspected overdose, contact a Poison Control Center or seek emergency medical attention immediately. Treatment is generally supportive and symptomatic, focusing on maintaining vital functions.

> Important: Follow your healthcare provider's dosing instructions precisely. Do not adjust your dose or stop the medication without medical guidance, as this can lead to a 'rebound' increase in acid production.

While Ranitidine was generally well-tolerated by the majority of patients, some individuals experienced mild adverse reactions. The most frequently reported side effects include:

• Headache: This is the most common complaint and can range from mild to severe. It typically resolves as the body adjusts to the medication.
• Gastrointestinal Disturbances: Some patients reported constipation, diarrhea, nausea, or abdominal discomfort. These symptoms are usually transient.
• Dizziness: A feeling of lightheadedness or unsteadiness may occur, particularly when rising from a seated position.

These side effects occurred in a smaller percentage of the population but were still clinically significant:

Ranitidine should only be used under the supervision of a licensed healthcare provider. The most significant safety information regarding Ranitidine in the current medical landscape is the 2020 FDA withdrawal. Patients are advised not to use any remaining Ranitidine products they may have and to switch to alternative therapies such as famotidine (Pepcid), cimetidine (Tagamet), or PPIs like omeprazole (Prilosec), which have not shown the same NDMA contamination risks.

No FDA black box warnings were ever issued for Ranitidine during its time on the market. However, the global recall and withdrawal due to NDMA contamination represent the highest level of regulatory safety action taken against the drug.

• Masking Gastric Malignancy: Response to Ranitidine therapy does not preclude the presence of gastric malignancy (stomach cancer). If symptoms persist or recur shortly after completing treatment, further diagnostic evaluation (such as endoscopy) is necessary to rule out cancer.

There are few absolute contraindications for drug combinations with Ranitidine, but the following require extreme caution:

• Delavirdine: Ranitidine can significantly reduce the plasma concentrations of delavirdine by increasing gastric pH, potentially leading to a loss of virologic response and the development of resistance. Use of these drugs together is generally not recommended.

• Ketoconazole and Itraconazole: These antifungal medications require an acidic environment for proper absorption. By raising gastric pH, Ranitidine can significantly decrease their absorption and efficacy. If these must be used together, the antifungal should be taken at least 2 hours before the Ranitidine.
• Atazanavir: Similar to antifungals, the absorption of this HIV protease inhibitor is pH-dependent. Co-administration with Ranitidine may reduce atazanavir levels below the therapeutic threshold.

Ranitidine must NEVER be used in the following circumstances:

1. 1Hypersensitivity: Any patient with a known allergy or hypersensitivity to Ranitidine or any of the inactive ingredients in the formulation. Because of the potential for cross-sensitivity, it should also be avoided in patients who have had a severe allergic reaction to other H2 receptor antagonists (e.g., famotidine, cimetidine, nizatidine).
2. 2History of Acute Porphyria: Ranitidine has been associated with the precipitation of acute attacks in patients with this rare genetic metabolic disorder. The mechanism involves the induction of enzymes in the heme biosynthetic pathway.
3. 3Recalled Products: In jurisdictions like the United States, use of any Ranitidine product manufactured prior to the 2020 recall is absolutely contraindicated due to the risk of NDMA exposure.

Ranitidine is classified as FDA Pregnancy Category B. This means that animal reproduction studies have failed to demonstrate a risk to the fetus, but there are no adequate and well-controlled studies in pregnant women. Historically, Ranitidine was often used for the treatment of pregnancy-related heartburn when lifestyle changes and antacids were insufficient. However, because it crosses the placenta, it should only be used during pregnancy if clearly needed and under the direct supervision of an obstetrician. Most experts recommend avoiding any medication during the first trimester unless absolutely necessary.

Ranitidine is excreted in human breast milk. The milk-to-plasma ratio has been measured at approximately 1:1 to 4:1. While no serious adverse effects have been reported in nursing infants, the potential for affecting the infant's gastric acidity or causing other pharmacological effects exists. Nursing mothers should consult their healthcare provider to weigh the benefits of treatment against the potential risks to the infant. Alternatives with lower milk excretion may be considered.

Ranitidine was approved for use in children as young as 1 month old for the treatment of GERD and ulcers. Clinical trials in pediatric populations showed a side effect profile similar to that seen in adults. However, the 2020 recall has led most pediatricians to switch to famotidine or other alternatives. It is not approved for use in neonates (under 1 month of age) due to a lack of safety data and concerns regarding the risk of necrotizing enterocolitis (NEC) in premature infants treated with acid-suppressing drugs.

Ranitidine is a specific, competitive antagonist of histamine at the H2-receptor sites. It does not possess significant anticholinergic activity and does not affect H1-receptors. The drug's primary site of action is the parietal cell of the stomach. By binding to the H2 receptor, Ranitidine prevents histamine from activating the adenylate cyclase enzyme. This inhibition prevents the rise in intracellular cAMP, which is the necessary signal for the H+/K+ ATPase pump to begin secreting protons (acid) into the stomach. Ranitidine inhibits both daytime and nocturnal basal gastric acid secretion, as well as secretion stimulated by food, histamine, pentagastrin, and insulin.

Ranitidine exhibits a clear dose-response relationship regarding the inhibition of gastric acid. A single 150 mg oral dose can suppress acid secretion for up to 12 hours. It also reduces the total volume of gastric juice and the secretion of pepsin. The drug has no effect on lower esophageal sphincter (LES) pressure or gastric emptying time. It does not significantly affect the secretion of hormones like gastrin, insulin, or glucagon.

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