ZANTAC® 150
(ranitidine hydrochloride)
Tablets, USP
ZANTAC® 300
(ranitidine hydrochloride)
Tablets, USP
ZANTAC® 25
(ranitidine hydrochloride effervescent)
EFFERdose® Tablets
ZANTAC®
(ranitidine hydrochloride)
Syrup, USP

The active ingredient in ZANTAC 150 Tablets, ZANTAC 300 Tablets, ZANTAC 25 EFFERdose Tablets, and ZANTAC Syrup is ranitidine hydrochloride (HCl), USP, a histamine H₂-receptor antagonist. Chemically it is N[2-[[[5-[(dimethylamino)methyl]-2-furanyl]methyl]thio]ethyl]-N′-methyl-2-nitro-1,1-ethenediamine, HCl. It has the following structure:

The empirical formula is C₁₃H₂₂N₄O₃S•HCl, representing a molecular weight of 350.87.

Ranitidine HCl is a white to pale yellow, granular substance that is soluble in water. It has a slightly bitter taste and sulfurlike odor.

Each ZANTAC 150 Tablet for oral administration contains 168 mg of ranitidine HCl equivalent to 150 mg of ranitidine. Each tablet also contains the inactive ingredients FD&C Yellow No. 6 Aluminum Lake, hypromellose, magnesium stearate, microcrystalline cellulose, titanium dioxide, triacetin, and yellow iron oxide.

Each ZANTAC 300 Tablet for oral administration contains 336 mg of ranitidine HCl equivalent to 300 mg of ranitidine. Each tablet also contains the inactive ingredients croscarmellose sodium, D&C Yellow No. 10 Aluminum Lake, hypromellose, magnesium stearate, microcrystalline cellulose, titanium dioxide, and triacetin.

ZANTAC 25 EFFERdose Tablets for oral administration is an effervescent formulation of ranitidine that must be dissolved in water before use. Each individual tablet contains 28 mg of ranitidine HCl equivalent to 25 mg of ranitidine and the following inactive ingredients: aspartame, monosodium citrate anhydrous, povidone, and sodium bicarbonate. Each tablet also contains sodium benzoate. The total sodium span of each tablet is 30.52 mg (1.33 mEq) per 25 mg of ranitidine.

Each 1 mL of ZANTAC Syrup contains 16.8 mg of ranitidine HCl equivalent to 15 mg of ranitidine. ZANTAC Syrup also contains the inactive ingredients alcohol (7.5%), butylparaben, dibasic sodium phosphate, hypromellose, peppermint flavor, monobasic potassium phosphate, propylparaben, purified water, saccharin sodium, sodium chloride, and sorbitol.

ZANTAC is a competitive, reversible inhibitor of the action of histamine at the histamine H₂-receptors, including receptors on the gastric cells. ZANTAC does not lower serum Ca++ in hypercalcemic states. ZANTAC is not an anticholinergic agent.

Serum concentrations necessary to inhibit 50% of stimulated gastric acid secretion are estimated to be 36 to 94 ng/mL. Following a single oral dose of 150 mg, serum concentrations of ZANTAC are in this range up to 12 hours. However, blood levels bear no consistent relationship to dose or degree of acid inhibition.

In a pharmacodynamic comparison of the EFFERdose with the ZANTAC Tablets, during the first hour after administration, the EFFERdose tablet formulation gave a significantly higher intragastric pH, by approximately 1 pH unit, compared to the ZANTAC tablets.

ZANTAC is indicated in:

• Short-term treatment of active duodenal ulcer. Most patients heal within 4 weeks. Studies available to date have not assessed the safety of ranitidine in uncomplicated duodenal ulcer for periods of more than 8 weeks.
• Maintenance therapy for duodenal ulcer patients at reduced dosage after healing of acute ulcers. No placebo-controlled comparative studies have been carried out for periods of longer than 1 year.
• The treatment of pathological hypersecretory conditions (e.g., Zollinger-Ellison syndrome and systemic mastocytosis).
• Short-term treatment of active, benign gastric ulcer. Most patients heal within 6 weeks and the usefulness of further treatment has not been demonstrated. Studies available to date have not assessed the safety of ranitidine in uncomplicated, benign gastric ulcer for periods of more than 6 weeks.
• Maintenance therapy for gastric ulcer patients at reduced dosage after healing of acute ulcers. Placebo-controlled studies have been carried out for 1 year.
• Treatment of GERD. Symptomatic relief commonly occurs within 24 hours after starting therapy with ZANTAC 150 mg b.i.d.
• Treatment of endoscopically diagnosed erosive esophagitis. Symptomatic relief of heartburn commonly occurs within 24 hours of therapy initiation with ZANTAC 150 mg q.i.d.
• Maintenance of healing of erosive esophagitis. Placebo-controlled trials have been carried out for 48 weeks.

Concomitant antacids should be given as needed for pain relief to patients with active duodenal ulcer; active, benign gastric ulcer; hypersecretory states; GERD; and erosive esophagitis.

ZANTAC is contraindicated for patients known to have hypersensitivity to the drug or any of the ingredients (see PRECAUTIONS).

General:

• Symptomatic response to therapy with ZANTAC does not preclude the presence of gastric malignancy.

• Since ZANTAC is excreted primarily by the kidney, dosage should be adjusted in patients with impaired renal function (see DOSAGE AND ADMINISTRATION). Caution should be observed in patients with hepatic dysfunction since ZANTAC is metabolized in the liver.

• Rare reports suggest that ZANTAC may precipitate acute porphyric attacks in patients with acute porphyria. ZANTAC should therefore be avoided in patients with a history of acute porphyria.

False-positive tests for urine protein with MULTISTIX^® may occur during ZANTAC therapy, and therefore testing with sulfosalicylic acid is recommended.

Although ZANTAC has been reported to bind weakly to cytochrome P-450 in vitro, recommended doses of the drug do not inhibit the action of the cytochrome P-450–linked oxygenase enzymes in the liver. However, there have been isolated reports of drug interactions that suggest that ZANTAC may affect the bioavailability of certain drugs by some mechanism as yet unidentified (e.g., a pH-dependent effect on absorption or a change in volume of distribution).

Increased or decreased prothrombin times have been reported during concurrent use of ranitidine and warfarin. However, in human pharmacokinetic studies with dosages of ranitidine up to 400 mg/day, no interaction occurred; ranitidine had no effect on warfarin clearance or prothrombin time. The possibility of an interaction with warfarin at dosages of ranitidine higher than 400 mg/day has not been investigated.

In a ranitidine-triazolam drug-drug interaction study, triazolam plasma concentrations were higher during b.i.d. dosing of ranitidine than triazolam given alone. The mean area under the triazolam concentration-time curve (AUC) values in 18- to 60-year-old subjects were 10% and 28% higher following administration of 75-mg and 150-mg ranitidine tablets, respectively, than triazolam given alone. In subjects older than 60 years of age, the mean AUC values were approximately 30% higher following administration of 75-mg and 150-mg ranitidine tablets. It appears that there were no changes in pharmacokinetics of triazolam and α-hydroxytriazolam, a major metabolite, and in their elimination. Reduced gastric acidity due to ranitidine may have resulted in an increase in the availability of triazolam. The clinical significance of this triazolam and ranitidine pharmacokinetic interaction is unknown.

There was no indication of tumorigenic or carcinogenic effects in life-span studies in mice and rats at dosages up to 2,000 mg/kg per day.

Ranitidine was not mutagenic in standard bacterial tests (Salmonella, Escherichia coli) for mutagenicity at concentrations up to the maximum recommended for these assays.

In a dominant lethal assay, a single oral dose of 1,000 mg/kg to male rats was without effect on the outcome of 2 matings per week for the next 9 weeks.

ZANTAC is secreted in human milk. Caution should be exercised when ZANTAC is administered to a nursing mother.

The safety and effectiveness of ZANTAC have been established in the age-group of 1 month to 16 years for the treatment of duodenal and gastric ulcers, gastroesophageal reflux disease and erosive esophagitis, and the maintenance of healed duodenal and gastric ulcer. Use of ZANTAC in this age-group is supported by adequate and well-controlled studies in adults, as well as additional pharmacokinetic data in pediatric patients and an analysis of the published literature (see CLINICAL PHARMACOLOGY: Pediatrics and DOSAGE AND ADMINISTRATION: Pediatric Use).

Safety and effectiveness in pediatric patients for the treatment of pathological hypersecretory conditions or the maintenance of healing of erosive esophagitis have not been established.

Safety and effectiveness in neonates (less than 1 month of age) have notbeen established (see CLINICAL PHARMACOLOGY: Pediatrics).

Of the total number of subjects enrolled in US and foreign controlled clinical trials of oral formulations of ZANTAC, for which there were subgroup analyses, 4,197 were 65 and over, while 899 were 75 and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

This drug is known to be substantially excreted by the kidney and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, caution should be exercised in dose selection, and it may be useful to monitor renal function (see CLINICAL PHARMACOLOGY: Pharmacokinetics: Geriatrics and DOSAGE AND ADMINISTRATION: Dosage Adjustment for Patients With Impaired Renal Function).

The following have been reported as events in clinical trials or in the routine management of patients treated with ZANTAC. The relationship to therapy with ZANTAC has been unclear in many cases. Headache, sometimes severe, seems to be related to administration of ZANTAC.

Rarely, malaise, dizziness, somnolence, insomnia, and vertigo. Rare cases of reversible mental confusion, agitation, depression, and hallucinations have been reported, predominantly in severely ill elderly patients. Rare cases of reversible blurred vision suggestive of a change in accommodation have been reported. Rare reports of reversible involuntary motor disturbances have been received.

As with other H₂-blockers, rare reports of arrhythmias such as tachycardia, bradycardia, atrioventricular block, and premature ventricular beats.

Constipation, diarrhea, nausea/vomiting, abdominal discomfort/pain, and rare reports of pancreatitis.

There have been occasional reports of hepatocellular, cholestatic, or mixed hepatitis, with or without jaundice. In such circumstances, ranitidine should be immediately discontinued. These events are usually reversible, but in rare circumstances death has occurred. Rare cases of hepatic failure have also been reported. In normal volunteers, SGPT values were increased to at least twice the pretreatment levels in 6 of 12 subjects receiving 100 mg q.i.d. intravenously for 7 days, and in 4 of 24 subjects receiving 50 mg q.i.d. intravenously for 5 days.

Rare reports of arthralgias and myalgias.

Blood count changes (leukopenia, granulocytopenia, and thrombocytopenia) have occurred in a few patients. These were usually reversible. Rare cases of agranulocytosis, pancytopenia, sometimes with marrow hypoplasia, and aplastic anemia and exceedingly rare cases of acquired immune hemolytic anemia have been reported.

Controlled studies in animals and man have shown no stimulation of any pituitary hormone by ZANTAC and no antiandrogenic activity, and cimetidine-induced gynecomastia and impotence in hypersecretory patients have resolved when ZANTAC has been substituted. However, occasional cases of gynecomastia, impotence, and loss of libido have been reported in male patients receiving ZANTAC, but the incidence did not differ from that in the general population.

Rash, including rare cases of erythema multiforme. Rare cases of alopecia and vasculitis.

A large epidemiological study suggested an increased risk of developing pneumonia in current users of histamine-2–receptor antagonists (H₂RAs) compared to patients who had stopped H₂RA treatment, with an observed adjusted relative risk of 1.63 (95% CI, 1.07–2.48). However, a causal relationship between use of H₂RAs and pneumonia has not been established.

Rare cases of hypersensitivity reactions (e.g., bronchospasm, fever, rash, eosinophilia), anaphylaxis, angioneurotic edema, and small increases in serum creatinine.

There has been limited experience with overdosage. Reported acute ingestions of up to 18 g orally have been associated with transient adverse effects similar to those encountered in normal clinical experience (see ADVERSE REACTIONS). In addition, abnormalities of gait and hypotension have been reported.

When overdosage occurs, the usual measures to remove unabsorbed material from the gastrointestinal tract, clinical monitoring, and supportive therapy should be employed.

Studies in dogs receiving dosages of ZANTAC in excess of 225 mg/kg per day have shown muscular tremors, vomiting, and rapid respiration. Single oral doses of 1,000 mg/kg in mice and rats were not lethal. Intravenous LD₅₀ values in mice and rats were 77 and 83 mg/kg, respectively.

The current recommended adult oral dosage of ZANTAC for duodenal ulcer is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) twice daily. An alternative dosage of 300 mg or 20 mL of syrup (4 teaspoonfuls of syrup equivalent to 300 mg of ranitidine) once daily after the evening meal or at bedtime can be used for patients in whom dosing convenience is important. The advantages of one treatment regimen compared to the other in a particular patient population have yet to be demonstrated (see Clinical Trials: Active Duodenal Ulcer). Smaller doses have been shown to be equally effective in inhibiting gastric acid secretion in US studies, and several foreign trials have shown that 100 mg twice daily is as effective as the 150-mg dose.

Antacid should be given as needed for relief of pain (see CLINICAL PHARMACOLOGY: Pharmacokinetics).

The current recommended adult oral dosage is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) at bedtime.

The current recommended adult oral dosage is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) twice a day. In some patients it may be necessary to administer ZANTAC 150-mg doses more frequently. Dosages should be adjusted to individual patient needs, and should continue as long as clinically indicated. Dosages up to 6 g/day have been employed in patients with severe disease.

The current recommended adult oral dosage is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) twice a day.

The current recommended adult oral dosage is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) at bedtime.

The current recommended adult oral dosage is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) twice a day.

The current recommended adult oral dosage is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) 4 times a day.

The current recommended adult oral dosage is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) twice a day.

The safety and effectiveness of ZANTAC have been established in the age-group of 1 month to 16 years. There is insufficient information about the pharmacokinetics of ZANTAC in neonatal patients (less than 1 month of age) to make dosing recommendations.

The following 3 subsections provide dosing information for each of the pediatric indications. Also, see the subsection on Preparation of ZANTAC 25 EFFERdose Tablets, below.

On the basis of experience with a group of subjects with severely impaired renal function treated with ZANTAC, the recommended dosage in patients with a creatinine clearance <50 mL/min is 150 mg or 10 mL of syrup (2 teaspoonfuls of syrup equivalent to 150 mg of ranitidine) every 24 hours. Should the patient's condition require, the frequency of dosing may be increased to every 12 hours or even further with caution. Hemodialysis reduces the level of circulating ranitidine. Ideally, the dosing schedule should be adjusted so that the timing of a scheduled dose coincides with the end of hemodialysis.

Elderly patients are more likely to have decreased renal function, therefore caution should be exercised in dose selection, and it may be useful to monitor renal function (see CLINICAL PHARMACOLOGY: Pharmacokinetics: Geriatrics and PRECAUTIONS: Geriatric Use).

Tablets should not be chewed, swallowed whole, or dissolved on the tongue. Dissolve 1 tablet in no less than 5 mL (1 teaspoonful) of water in an appropriate measuring cup. Wait until the tablet is completely dissolved before administering the solution to the infant/child. The solution may be administered by medicine dropper or oral syringe for infants.

ZANTAC 150 Tablets (ranitidine HCl equivalent to 150 mg of ranitidine) are peach, film-coated, 5-sided tablets embossed with "ZANTAC 150" on one side and "Glaxo" on the other. They are available in bottles of 60 (NDC 0173-0344-42), 180 (NDC 0173-0344-17), and 500 (NDC 0173-0344-14) tablets.

ZANTAC 300 Tablets (ranitidine HCl equivalent to 300 mg of ranitidine)are yellow, film-coated, capsule-shaped tablets embossed with "ZANTAC 300" on one side and "Glaxo" on the other. They are available in bottles of 30 (NDC 0173-0393-40) tablets.

Store between 15°and 30°C (59°and 86°F) in a dry place. Protect from light. Replace cap securely after each opening.

ZANTAC 25 EFFERdose Tablets (ranitidine HCl equivalent to 25 mg of ranitidine) are white to pale yellow, round, flat-faced, bevel-edged tablets embossed with “GS” on one side and “25C” on the other side. They are packaged in foil strips and are available in a carton of 60 (NDC 0173-0734-00) tablets.

Store between 2°and 30°C (36° and 86°F).

ZANTAC Syrup, a clear, pale yellow, peppermint-flavored liquid, contains 16.8 mg of ranitidine HCl equivalent to 15 mg of ranitidine per 1 mL (75 mg/5 mL) in bottles of 16 fluid ounces (one pint) (NDC 0173-0383-54).

Store between 4° and 25°C (39° and 77°F). Dispense in tight, light-resistant containers as defined in the USP/NF.

GlaxoSmithKline

Research Triangle Park, NC 27709

ZANTAC and EFFERdose are registered trademarks of Warner-Lambert Company, used under license.

©2007, GlaxoSmithKline. All rights reserved.

June 2007 ZNT:1PI