ZANTAC®
(ranitidine hydrochloride)
Injection
ZANTAC®
(ranitidine hydrochloride)
Injection Premixed

The active ingredient in ZANTAC Injection and ZANTAC Injection Premixed is ranitidine hydrochloride (HCl), 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, hydrochloride. 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.

ZANTAC Injection is a clear, colorless to yellow, nonpyrogenic liquid. The yellow color of the liquid tends to intensify without adversely affecting potency. The pH of the injection solution is 6.7 to 7.3.

Each 1 mL of aqueous solution contains ranitidine 25 mg (as the hydrochloride); phenol 5 mg as preservative; and 0.96 mg of monobasic potassium phosphate and 2.4 mg of dibasic sodium phosphate as buffers.

Each 50 mL contains ranitidine HCl equivalent to 50 mg of ranitidine, sodium chloride 225 mg, and citric acid 15 mg and dibasic sodium phosphate 90 mg as buffers in water for injection. It contains no preservatives. The osmolarity of this solution is 180 mOsm/L (approx.), and the pH is 6.7 to 7.3.

The flexible plastic container is fabricated from a specially formulated, nonplasticized, thermoplastic co-polyester (CR3). Water can permeate from inside the container into the overwrap but not in amounts sufficient to affect the solution significantly. Solutions inside the plastic container also can leach out certain of the chemical components in very small amounts before the expiration period is attained. However, the safety of the plastic has been confirmed by tests in animals according to USP biological standards for plastic containers.

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 single IV or IM 50-mg doses, serum concentrations of ZANTAC are in this range for 6 to 8 hours.

ZANTAC Injection and ZANTAC Injection Premixed are indicated in some hospitalized patients with pathological hypersecretory conditions or intractable duodenal ulcers, or as an alternative to the oral dosage form for short-term use in patients who are unable to take oral medication.

ZANTAC Injection and ZANTAC Injection Premixed are contraindicated for patients known to have hypersensitivity to the drug.

• 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.
• In controlled studies in normal volunteers, elevations in SGPT have been observed when H₂-antagonists have been administered intravenously at greater than recommended dosages for 5 days or longer. Therefore, it seems prudent in patients receiving IV ranitidine at dosages ≥100 mg q.i.d. for periods of 5 days or longer to monitor SGPT daily (from day 5) for the remainder of IV therapy.
• Bradycardia in association with rapid administration of ZANTAC Injection has been reported rarely, usually in patients with factors predisposing to cardiac rhythm disturbances. Recommended rates of administration should not be exceeded (see DOSAGE AND ADMINISTRATION).
• 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 therapy with ZANTAC, and therefore testing with sulfosalicylic acid is recommended.

Although ZANTAC has been reported to bind weakly to cytochrome P-450 invitro, 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 oral dosages up to 2,000 mg/kg per day.

Ranitidine was not mutagenic in standard bacterial tests (Salmonella, Escherichiacoli) 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 two 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 Injection have been established in the age-group of 1 month to 16 years for the treatment of duodenal 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.

Safety and effectiveness in pediatric patients for the treatment of pathological hypersecretory conditions have not been established.

Limited data in neonatal patients (less than one month of age) receiving ECMO suggest that ZANTAC may be useful and safe for increasing gastric pH for patients at risk of gastrointestinal hemorrhage.

Clinical studies of ZANTAC Injection did not include sufficient numbers of subjects aged 65 and over to determine whether they responded differently from younger subjects. However, in clinical studies of oral formulations of ZANTAC, of the total number of subjects enrolled in US and foreign controlled clinical trials, 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: Geriatric Use and DOSAGE AND ADMINISTRATION: Dosage Adjustment for Patients with Impaired Renal Function).

Transient pain at the site of IM injection has been reported. Transient local burning or itching has been reported with IV administration of ZANTAC.

The following have been reported as events in clinical trials or in the routine management of patients treated with oral or parenteral 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, asystole, atrioventricular block, and premature ventricular beats.

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

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. 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.

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 humans 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. Rarecases 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 H₂RAs 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 virtually no experience with overdosage with ZANTAC Injection and limited experience with oral doses of ranitidine. 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, 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.

In some hospitalized patients with pathological hypersecretory conditions or intractable duodenal ulcers, or in patients who are unable to take oral medication, ZANTAC may be administered parenterally according to the following recommendations:

While limited data exist on the administration of IV ranitidine to children, the recommended dose in pediatric patients is for a total daily dose of 2 to 4 mg/kg, to be divided and administered every 6 to 8 hours, up to a maximum of 50 mg given every 6 to 8 hours. This recommendation is derived from adult clinical studies and pharmacokinetic data in pediatric patients. Limited data in neonatal patients (less than one month of age) receiving ECMO have shown that a dose of 2 mg/kg is usually sufficient to increase gastric pH to >4 for at least 15 hours. Therefore, doses of 2 mg/kg given every 12 to 24 hours or as a continuous infusion should be considered.

The administration of ranitidine as a continuous infusion has not been evaluated in patients with impaired renal function. 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 50 mg every 18 to 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: Geriatric Use and PRECAUTIONS: Geriatric Use).

Undiluted, ZANTAC Injection tends to exhibit a yellow color that may intensify over time without adversely affecting potency. ZANTAC Injection is stable for 48 hours at room temperature when added to or diluted with most commonly used IV solutions, e.g., 0.9% sodium chloride injection, 5% dextrose injection, 10% dextrose injection, lactated ringer's injection, or 5% sodium bicarbonate injection.

ZANTAC Injection Premixed in flexible plastic containers is sterile through the expiration date on the label when stored under recommended conditions.

Note: Parenteral drug products should be inspected visually for particulate matter and discoloration before administration whenever solution and container permit.

ZANTAC Injection, 25 mg/mL, containing phenol 0.5% as preservative, is available as follows:

NDC 0173-0362-38, 2-mL single-dose vials (Tray of 10)

NDC 0173-0363-01, 6-mL multidose vials (Singles)

Store between 4° and 25°C (39° and 77°F); excursions permitted to 30°C (86°F). Protect from light.

ZANTAC Injection Premixed, 50 mg/50 mL, in 0.45% sodium chloride, is available as a sterile, premixed solution for IV administration in single-dose, flexible plastic containers (NDC 0173-0441-00) (case of 24). It contains no preservatives.

Store between 2° and 25°C (36° and 77°F). Protect from light.

Exposure of pharmaceutical products to heat should be minimized. Avoid excessive heat; however, brief exposure up to 40°C does not adversely affect the product. Protect from freezing.

GlaxoSmithKline

Research Triangle Park, NC 27709

ZANTAC^® Injection:

GlaxoSmithKline

Research Triangle Park, NC 27709

ZANTAC^® Injection Premixed:

Manufactured for GlaxoSmithKline

Research Triangle Park, NC 27709

by Hospira, Inc., North Chicago, IL 60064

ZANTAC is a registered trademark of Warner-Lambert Company, used under license.

©2006, GlaxoSmithKline. All rights reserved.

July 2006 RL-2312