ZANTAC®

ZANTAC® 150
(ranitidine hydrochloride) Tablets, USP
ZANTAC® 300
(ranitidine hydrochloride) Tablets, USP
ZANTAC® 25
(ranitidine hydrochloride effervescent) EFFERdose® Tablets
(ranitidine hydrochloride) Syrup, USP
DRUG DESCRIPTION
What are the possible side effects of ranitidine (Zantac, Zantac 150, Zantac 300, Zantac 75, Zantac EFFERdose)?
Stop using ranitidine and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
chest pain, fever, feeling short of breath, coughing up green or yellow mucus;
easy bruising or bleeding, unusual weakness;
fast or slow heart rate; …
Read All Potential Side Effects and See Pictures of Zantac »
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]-2furanyl]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 content 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.
Last reviewed on RxList: 12/6/2010
Zantac Indications & Dosage

INDICATIONS
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 twice daily.
Treatment of endoscopically diagnosed erosive esophagitis. Symptomatic relief of heartburn commonly occurs within 24 hours of therapy initiation with ZANTAC 150 mg 4 times daily.
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.
DOSAGE AND ADMINISTRATION
Active Duodenal Ulcer
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).
Maintenance of Healing of Duodenal Ulcers
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.
Pathological Hypersecretory Conditions (such as Zollinger-Ellison syndrome)
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 daily. 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.
Benign Gastric Ulcer
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 daily.
Maintenance of Healing of Gastric Ulcers
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.
GERD
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 daily.
Erosive Esophagitis
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 daily.
Maintenance of Healing of Erosive Esophagitis
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 daily.
Pediatric Use
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.
Treatment of Duodenal and Gastric Ulcers
The recommended oral dose for the treatment of active duodenal and gastric ulcers is 2 to 4 mg/kg twice daily to a maximum of 300 mg/day. This recommendation is derived from adult clinical studies and pharmacokinetic data in pediatric patients.
Maintenance of Healing of Duodenal and Gastric Ulcers
The recommended oral dose for the maintenance of healing of duodenal and gastric ulcers is 2 to 4 mg/kg once daily to a maximum of 150 mg/day. This recommendation is derived from adult clinical studies and pharmacokinetic data in pediatric patients.
Treatment of GERD and Erosive Esophagitis
Although limited data exist for these conditions in pediatric patients, published literature supports a dosage of 5 to 10 mg/kg/day, usually given as 2 divided doses.
Dosage Adjustment for 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 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). Preparation of ZANTAC 25 EFFERdose Tablets 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 to infants by medicine dropper or oral syringe. HOW SUPPLIED 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. Revised April 2009. Last reviewed on RxList: 12/6/2010 Zantac Side Effects & Drug Interactions SIDE EFFECTS 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. Central Nervous System 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. Cardiovascular As with other H2-blockers, rare reports of arrhythmias such as tachycardia, bradycardia, atrioventricular block, and premature ventricular beats. Gastrointestinal Constipation, diarrhea, nausea/vomiting, abdominal discomfort/pain, and rare reports of pancreatitis. Hepatic 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 intravenously 4 times daily for 7 days, and in 4 of 24 subjects receiving 50 mg intravenously 4 times daily for 5 days. Musculoskeletal Rare reports of arthralgias and myalgias. Hematologic 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. Endocrine 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 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. Rare cases of breast symptoms and conditions, including galactorrhea and gynecomastia, have been reported in both males and females. Integumentary Rash, including rare cases of erythema multiforme. Rare cases of alopecia and vasculitis. Respiratory 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, 1.072.48). However, a causal relationship between use of H2RAs and pneumonia has not been established. Other Rare cases of hypersensitivity reactions (e.g., bronchospasm, fever, rash, eosinophilia), anaphylaxis, angioneurotic edema, acute interstitial nephritis, and small increases in serum creatinine. DRUG INTERACTIONS Ranitidine has been reported to affect the bioavailability of other drugs through several different mechanisms such as competition for renal tubular secretion, alteration of gastric pH, and inhibition of cytochrome P450 enzymes. Procainamide Ranitidine, a substrate of the renal organic cation transport system, may affect the clearance of other drugs eliminated by this route. High doses of ranitidine (e.g., such as those used in the treatment of Zollinger-Ellison syndrome) have been shown to reduce the renal excretion of procainamide and N-acetylprocainamide resulting in increased plasma levels of these drugs. Although this interaction is unlikely to be clinically relevant at usual ranitidine doses, it may be prudent to monitor for procainamide toxicity when administered with oral ranitidine at a dose exceeding 300 mg per day. Warfarin There have been reports of altered prothrombin time among patients on concomitant warfarin and ranitidine therapy. Due to the narrow therapeutic index, close monitoring of increased or decreased prothrombin time is recommended during concurrent treatment with ranitidine. Ranitidine may alter the absorption of drugs in which gastric pH is an important determinant of bioavailability. This can result in either an increase in absorption (e.g., triazolam, midazolam, glipizide) or a decrease in absorption (e.g., ketoconazole, atazanavir, delavirdine, gefitinib). Appropriate clinical monitoring is recommended. Atazanavir Atazanavir absorption may be impaired based on known interactions with other agents that increase gastric pH. Use with caution. See atazanavir label for specific recommendations. Delavirdine Delavirdine absorption may be impaired based on known interactions with other agents that increase gastric pH. Chronic use of H2-receptor antagonists with delavirdine is not recommended. Gefitinib Gefitinib exposure was reduced by 44% with the coadministration of ranitidine and sodium bicarbonate (dosed to maintain gastric pH above 5.0). Use with caution. Glipizide In diabetic patients, glipizide exposure was increased by 34% following a single 150-mg dose of oral ranitidine. Use appropriate clinical monitoring when initiating or discontinuing ranitidine. Ketoconazole Oral ketoconazole exposure was reduced by up to 95% when oral ranitidine was coadministered in a regimen to maintain a gastric pH of 6 or above. The degree of interaction with usual dose of ranitidine (150 mg twice daily) is unknown. Midazolam Oral midazolam exposure in 5 healthy volunteers was increased by up to 65% when administered with oral ranitidine at a dose of 150 mg twice daily. However, in another interaction study in 8 volunteers receiving IV midazolam, a 300 mg oral dose of ranitidine increased midazolam exposure by about 9%. Monitor patients for excessive or prolonged sedation when ranitidine is coadministered with oral midazolam. Triazolam Triazolam exposure in healthy volunteers was increased by approximately 30% when administered with oral ranitidine at a dose of 150 mg twice daily. Monitor patients for excessive or prolonged sedation. Last reviewed on RxList: 12/6/2010 Zantac Warnings & Precautions WARNINGS No information provided. 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. Laboratory Tests False-positive tests for urine protein with MULTISTIX® may occur during therapy with ZANTAC, and therefore testing with sulfosalicylic acid is recommended. Carcinogenesis, Mutagenesis, Impairment of Fertility 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/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. Pregnancy Teratogenic Effects - Pregnancy Category B Reproduction studies have been performed in rats and rabbits at doses up to 160 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to ZANTAC. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Nursing Mothers Ranitidine is secreted in human milk. Caution should be exercised when ZANTAC is administered to a nursing mother. Pediatric Use 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 not been established (see CLINICAL PHARMACOLOGY: Pediatrics). Geriatric Use 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). Last reviewed on RxList: 12/6/2010 Zantac Overdosage & Contraindications OVERDOSE 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/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. CONTRAINDICATIONS ZANTAC is contraindicated for patients known to have hypersensitivity to the drug or any of the ingredients (see PRECAUTIONS). Last reviewed on RxList: 12/6/2010 Zantac Clinical Pharmacology CLINICAL PHARMACOLOGY 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. Pharmacokinetics Absorption ZANTAC is 50% absorbed after oral administration, compared to an intravenous (IV) injection with mean peak levels of 440 to 545 ng/mL occurring 2 to 3 hours after a 150-mg dose. The syrup and EFFERdose formulations are bioequivalent to the tablets. Absorption is not significantly impaired by the administration of food or antacids. Propantheline slightly delays and increases peak blood levels of ranitidine, probably by delaying gastric emptying and transit time. In one study, simultaneous administration of high-potency antacid (150 mmol) in fasting subjects has been reported to decrease the absorption of ZANTAC. Distribution The volume of distribution is about 1.4 L/kg. Serum protein binding averages 15%. Metabolism In humans, the N-oxide is the principal metabolite in the urine; however, this amounts to < 4% of the dose. Other metabolites are the S-oxide (1%) and the desmethyl ranitidine (1%). The remainder of the administered dose is found in the stool. Studies in patients with hepatic dysfunction (compensated cirrhosis) indicate that there are minor, but clinically insignificant, alterations in ranitidine half-life, distribution, clearance, and bioavailability. Excretion The principal route of excretion is the urine, with approximately 30% of the orally administered dose collected in the urine as unchanged drug in 24 hours. Renal clearance is about 410 mL/min, indicating active tubular excretion. The elimination half-life is 2.5 to 3 hours. Four patients with clinically significant renal function impairment (creatinine clearance 25 to 35 mL/min) administered 50 mg of ranitidine intravenously had an average plasma half-life of 4.8 hours, a ranitidine clearance of 29 mL/min, and a volume of distribution of 1.76 L/kg. In general, these parameters appear to be altered in proportion to creatinine clearance (see DOSAGE AND ADMINISTRATION). Geriatrics The plasma half-life is prolonged and total clearance is reduced in the elderly population due to a decrease in renal function. The elimination half-life is 3 to 4 hours. Peak levels average 526 ng/mL following a 150-mg twice-daily dose and occur in about 3 hours (see PRECAUTIONS: Geriatric Use and DOSAGE AND ADMINISTRATION: Dosage Adjustment for Patients With Impaired Renal Function). Pediatrics There are no significant differences in the pharmacokinetic parameter values for ranitidine in pediatric patients (from 1 month up to 16 years of age) and healthy adults when correction is made for body weight. The average bioavailability of ranitidine given orally to pediatric patients is 48% which is comparable to the bioavailability of ranitidine in the adult population. All other pharmacokinetic parameter values (t½, Vd, and CL) are similar to those observed with intravenous ranitidine use in pediatric patients. Estimates of Cmax and Tmax are displayed in Table 1. Table 1: Ranitidine Pharmacokinetics in Pediatric Patients Following Oral Dosing Population(age) n Dosage Form (dose) Cmax (ng/mL) Tmax (hours) Gastric or duodenal ulcer (3.5 to 16 years) 12 Tablets (1 to 2 mg/kg) 54 to 492 2.0 Otherwise healthy requiring ZANTAC (0.7 to 14 years, Single dose) 10 Syrup (2 mg/kg) 244 1.61 Otherwise healthy requiring ZANTAC (0.7 to 14 years, Multiple dose) 10 Syrup (2 mg/kg) 320 1.66 Plasma clearance measured in 2 neonatal patients (less than 1 month of age) was considerably lower (3 mL/min/kg) than children or adults and is likely due to reduced renal function observed in this population (see PRECAUTIONS: Pediatric Use and DOSAGE AND ADMINISTRATION: Pediatric Use). Pharmacodynamics 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 ranitidine 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. Antisecretory Activity 1. Effects on Acid Secretion: ZANTAC inhibits both daytime and nocturnal basal gastric acid secretions as well as gastric acid secretion stimulated by food, betazole, and pentagastrin, as shown in Table 2. Table 2: Effect of Oral ZANTAC on Gastric Acid Secretion Time After Dose, hours % Inhibition of Gastric Acid Output by Dose, mg 75-80 100 150 200 Basal Up to 4 99 95 Nocturnal Up to 13 95 96 92 Betazole Up to 3 97 99 Pentagastrin Up to 5 58 72 72 80 Meal Up to 3 73 79 95 It appears that basal-, nocturnal-, and betazole-stimulated secretions are most sensitive to inhibition by ZANTAC, responding almost completely to doses of 100 mg or less, while pentagastrin- and food-stimulated secretions are more difficult to suppress. 2. Effects on Other Gastrointestinal Secretions: Pepsin: Oral ZANTAC does not affect pepsin secretion. Total pepsin output is reduced in proportion to the decrease in volume of gastric juice. Intrinsic Factor: Oral ZANTAC has no significant effect on pentagastrin-stimulated intrinsic factor secretion. Serum Gastrin: ZANTAC has little or no effect on fasting or postprandial serum gastrin. Other Pharmacologic Actions Gastric bacterial flora—increase in nitrate-reducing organisms, significance not known. Prolactin levels—no effect in recommended oral or IV dosage, but small, transient, dose-related increases in serum prolactin have been reported after IV bolus injections of 100 mg or more. Other pituitary hormones—no effect on serum gonadotropins, TSH, or GH. Possible impairment of vasopressin release. No change in cortisol, aldosterone, androgen, or estrogen levels. No antiandrogenic action. No effect on count, motility, or morphology of sperm. Pediatrics: Oral doses of 6 to 10 mg/kg/day in 2 or 3 divided doses maintain gastric pH > 4 throughout most of the dosing interval.
Clinical Trials
Active Duodenal Ulcer: In a multicenter, double-blind, controlled, US study of endoscopically diagnosed duodenal ulcers, earlier healing was seen in the patients treated with ZANTAC as shown in Table 3.
Table 3: Duodenal Ulcer Patient Healing Rates
ZANTAC* Placebo*
Number Entered Healed/ Evaluable Number Entered Healed/ Evaluable
Outpatients
Week 2 195 69/182(38%)† 188 31/164(19%)
Week 4 137/187(73%)† 76/168(45%)
*All patients were permitted antacids as needed for relief of pain.
†P < 0.0001. In these studies, patients treated with ZANTAC reported a reduction in both daytime and nocturnal pain, and they also consumed less antacid than the placebo-treated patients. Table 4: Mean Daily Doses of Antacid Ulcer Healed Ulcer Not Healed ZANTAC 0.06 0.71 Placebo 0.71 1.43 Foreign studies have shown that patients heal equally well with 150 mg twice daily and 300 mg at bedtime (85% versus 84%, respectively) during a usual 4-week course of therapy. If patients require extended therapy of 8 weeks, the healing rate may be higher for 150 mg twice daily as compared to 300 mg at bedtime (92% versus 87%, respectively). Studies have been limited to short-term treatment of acute duodenal ulcer. Patients whose ulcers healed during therapy had recurrences of ulcers at the usual rates. Maintenance Therapy in Duodenal Ulcer: Ranitidine has been found to be effective as maintenance therapy for patients following healing of acute duodenal ulcers. In 2 independent, double-blind, multicenter, controlled trials, the number of duodenal ulcers observed was significantly less in patients treated with ZANTAC (150 mg at bedtime) than in patients treated with placebo over a 12-month period. Table 5: Duodenal Ulcer Prevalence Multicenter Trial Double-Blind, Multicenter, Placebo-Controlled Trials Drug Duodenal Ulcer Prevalence 0-4 Months 0-8 Months 0-12 Months No. of Patients USA RAN 20%* 24%* 35%* 138 PLC 44% 54% 59% 139 Foreign RAN 12%* 21%* 28%* 174 PLC 56% 64% 68% 165 % = Life table estimate. * = P < 0.05 (ZANTAC versus comparator). RAN = ranitidine (ZANTAC). PLC = placebo. As with other H2-antagonists, the factors responsible for the significant reduction in the prevalence of duodenal ulcers include prevention of recurrence of ulcers, more rapid healing of ulcers that may occur during maintenance therapy, or both. Gastric Ulcer: In a multicenter, double-blind, controlled, US study of endoscopically diagnosed gastric ulcers, earlier healing was seen in the patients treated with ZANTAC as shown in Table 6. Table 6: Gastric Ulcer Patient Healing Rates ZANTAC* Placebo* Number Entered Healed/ Evaluable Number Entered Healed/ Evaluable Outpatients Week 2 92 16/83 94 10/83 (19%) (12%) Week 6 50/73 35/69 (68%)† (51%) *All patients were permitted antacids as needed for relief of pain. †P = 0.009. In this multicenter trial, significantly more patients treated with ZANTAC became pain free during therapy. Maintenance of Healing of Gastric Ulcers: In 2 multicenter, double-blind, randomized, placebo-controlled, 12-month trials conducted in patients whose gastric ulcers had been previously healed, ZANTAC 150 mg at bedtime was significantly more effective than placebo in maintaining healing of gastric ulcers. Pathological Hypersecretory Conditions (such as Zollinger-Ellison syndrome): ZANTAC inhibits gastric acid secretion and reduces occurrence of diarrhea, anorexia, and pain in patients with pathological hypersecretion associated with Zollinger-Ellison syndrome, systemic mastocytosis, and other pathological hypersecretory conditions (e.g., postoperative, “short-gut” syndrome, idiopathic). Use of ZANTAC was followed by healing of ulcers in 8 of 19 (42%) patients who were intractable to previous therapy. Gastroesophageal Reflux Disease (GERD): In 2 multicenter, double-blind, placebo-controlled, 6-week trials performed in the United States and Europe, ZANTAC 150 mg twice daily was more effective than placebo for the relief of heartburn and other symptoms associated with GERD. Ranitidine-treated patients consumed significantly less antacid than did placebo-treated patients. The US trial indicated that ZANTAC 150 mg twice daily significantly reduced the frequency of heartburn attacks and severity of heartburn pain within 1 to 2 weeks after starting therapy. The improvement was maintained throughout the 6-week trial period. Moreover, patient response rates demonstrated that the effect on heartburn extends through both the day and night time periods. In 2 additional US multicenter, double-blind, placebo-controlled, 2-week trials, ZANTAC 150 mg twice daily was shown to provide relief of heartburn pain within 24 hours of initiating therapy and a reduction in the frequency of severity of heartburn. In these trials, ZANTAC EFFERdose Tablets were shown to provide heartburn relief within 45 minutes of dosing. Erosive Esophagitis: In 2 multicenter, double-blind, randomized, placebo-controlled, 12-week trials performed in the United States, ZANTAC 150 mg 4 times daily was significantly more effective than placebo in healing endoscopically diagnosed erosive esophagitis and in relieving associated heartburn. The erosive esophagitis healing rates were as follows: Table 7: Erosive Esophagitis Patient Healing Rates Healed/Evaluable Placebo* n = 229 ZANTAC 150 mg 4 times daily* n = 215 Week 4 43/198 (22%) 96/206 (47%)† Week 8 63/176 (36%) 142/200 (71%)† Week 12 92/159 (58%) 162/192 (84%)† *All patients were permitted antacids as needed for relief of pain. †P < 0.001 versus placebo. No additional benefit in healing of esophagitis or in relief of heartburn was seen with a ranitidine dose of 300 mg 4 times daily. Maintenance of Healing of Erosive Esophagitis: In 2 multicenter, double-blind, randomized, placebo-controlled, 48-week trials conducted in patients whose erosive esophagitis had been previously healed, ZANTAC 150 mg twice daily was significantly more effective than placebo in maintaining healing of erosive esophagitis. Last reviewed on RxList: 12/6/2010 Zantac Medication Guide PATIENT INFORMATION Phenylketonurics ZANTAC 25 EFFERdose Tablets contain phenylalanine 2.81 mg per 25 mg of ranitidine. ZANTAC EFFERdose Tablets should not be chewed, swallowed whole, or dissolved on the tongue. Last reviewed on RxList: 12/6/2010 Zantac Consumer IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you. RANITIDINE TABLET - ORAL (ran-IT-uh-deen) COMMON BRAND NAME(S): Zantac USES: Ranitidine is used to treat ulcers of the stomach and intestines and prevent them from returning after treatment. This medication is also used to treat and prevent certain stomach and throat (esophagus) problems caused by too much stomach acid (e.g., Zollinger-Ellison syndrome, erosive esophagitis) or a backward flow of stomach acid into the esophagus (gastroesophageal reflux disease-GERD). Ranitidine is known as an H2 histamine blocker. It works by reducing the amount of acid in your stomach. This helps heal and prevent ulcers and improves symptoms such as heartburn and stomach pain. This medication is also available without a prescription. It is used to prevent and treat heartburn and other symptoms caused by too much acid in the stomach (acid indigestion). If you are taking this medication for self-treatment, it is important to read the manufacturer's package instructions carefully so you know when to consult your doctor or pharmacist. HOW TO USE: Take this medication by mouth with or without food, usually once or twice daily or as directed by your doctor. It may be prescribed 4 times a day for some conditions. If you are taking this medication once daily, it is usually taken after the evening meal or before bedtime. The dosage and length of treatment are based on your medical condition and response to therapy. In children, dosage may also be based on body weight. Follow your doctor's instructions carefully. You may take other medications (e.g., antacids) for your condition as recommended by your doctor. Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time(s) each day. Do not increase your dose or take it more often than prescribed. Do not stop taking this without your doctor's approval because this may delay healing of the ulcer. If you are using nonprescription ranitidine for self-treatment of acid indigestion or heartburn, take 1 tablet by mouth with a glass of water as needed. To prevent heartburn, take 1 tablet by mouth with a glass of water 30-60 minutes before eating food or drinking beverages that cause heartburn. Do not take more than 2 tablets in 24 hours unless directed by your doctor. Do not take for more than 14 days in a row without talking with your doctor. Inform your doctor if your condition does not improve or if it worsens. Zantac Consumer (continued) SIDE EFFECTS: Headache, dizziness, constipation or diarrhea may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. If your doctor has directed you to use this medication, remember that he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor immediately if any of these unlikely but serious side effects occur: blurred vision, mental/mood changes (e.g., agitation, confusion, depression, hallucinations). Tell your doctor immediately if any of these rare but very serious side effects occur: easy bleeding/bruising, enlarged breasts, severe tiredness, fast/slow/irregular heartbeat, signs of infection (e.g., fever, persistent sore throat, cough), severe stomach/abdominal pain, dark urine, yellowing skin/eyes. A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 begin_of_the_skype_highlighting 1-800-FDA-1088 end_of_the_skype_highlighting. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345 begin_of_the_skype_highlighting 1-866-234-2345 end_of_the_skype_highlighting. PRECAUTIONS: Before taking ranitidine, tell your doctor or pharmacist if you are allergic to it; or to other H2 histamine blockers (e.g., cimetidine, famotidine); or if you have any other allergies. This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: a certain blood disorder (porphyria). Before using this medication, tell your doctor or pharmacist your medical history, especially of: immune system problems, kidney problems, liver problems, lung diseases (e.g., asthma, chronic obstructive pulmonary disease-COPD), other stomach problems (e.g., tumors). Some symptoms may actually be signs of a more serious condition. Tell your doctor immediately if you have: heartburn combined with lightheadedness/sweating/dizziness, chest pain or shoulder/jaw pain (especially with trouble breathing), pain spreading to arms/neck/shoulders, unexplained weight loss. This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages. Do not use to treat children younger than 12 unless directed by the doctor. Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, elderly people may be at greater risk for side effects while using this drug. Caution is advised when using this drug in the elderly because they may be more sensitive to its effects, especially confusion and dizziness. Ranitidine should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. Ranitidine passes into breast milk. Consult your doctor before breast-feeding. Zantac Consumer (continued) DRUG INTERACTIONS: The effects of some drugs can change if you take other drugs or herbal products at the same time. This can increase your risk for serious side effects or may cause your medications not to work correctly. These drug interactions are possible, but do not always occur. Your doctor or pharmacist can often prevent or manage interactions by changing how you use your medications or by close monitoring. To help your doctor and pharmacist give you the best care, be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before starting treatment with this product. While using this product, do not start, stop, or change the dosage of any other medicines you are using without your doctor's approval. Some products that may interact with this drug include: procainamide, propantheline, warfarin. This medication decreases the amount of acid in your stomach. This can change the amount of medication absorbed from your stomach which may affect how these medications work. Examples of affected drugs include atazanavir, delavirdine, dasatinib, gefitinib, glipizide, raltegravir, triazolam among others. Azole antifungals such as ketoconazole may also be affected. This medication can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include metoprolol and phenytoin among others. Check the labels on all your medicines because they may contain aspirin or aspirin-like NSAIDs (e.g., ibuprofen, naproxen) that can cause stomach irritation/ulcers. Ask your pharmacist about the safe use of those products. Low-dose aspirin, as prescribed by your doctor for specific medical reasons such as heart attack or stroke prevention (usually at dosages of 81-325 milligrams per day), should be continued. Consult your doctor or pharmacist for more details. This medication and similar H2 histamine blockers (e.g., cimetidine, famotidine) are available both over-the-counter and by prescription. Do not take them at the same time. This medication may interfere with certain laboratory tests (e.g., urine protein), possibly causing false test results. Make sure laboratory personnel and your doctors know you use this drug. This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222 begin_of_the_skype_highlighting 1-800-222-1222 end_of_the_skype_highlighting. Canadian residents should call their local poison control center directly. Symptoms of overdose may include difficulty walking, severe dizziness/fainting. NOTES: Do not share this medication with others. Lifestyle changes such as stress reduction programs, stopping smoking, limiting alcohol, and diet changes (e.g., avoiding caffeine, certain spices) may increase the effectiveness of this medication. Talk to your doctor or pharmacist about lifestyle changes that might benefit you. Laboratory and/or medical tests (e.g., endoscopy, kidney function tests) may be performed to monitor your progress or check for side effects. Consult your doctor for more details. MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up. STORAGE: Store the US product in a tightly closed container at room temperature between 59-86 degrees F (15-30 degrees C) away from moisture and light. Store the nonprescription medication at room temperature between 68-86 degrees F (20-30 degrees C). Store the Canadian product in a tightly closed container between 35.6 and 86 degrees F (2 and 30 degrees C) away from moisture and light. Do not store in the bathroom. Keep all medicines away from children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.