Omeprazole/sodiium Bicarbonate

Omeprazole and Sodium Bicarbonate capsules are indicated in adults for the: short-term treatment of active duodenal ulcer. Most patients heal within four weeks. Some patients may require an additional four weeks of therapy. short-term treatment (4 to 8 weeks) of active benign gastric ulcer. treatment of heartburn and other symptoms associated with GERD for up to 4 weeks. short-term treatment (4 to 8 weeks) of EE due to acid-mediated GERD which has been diagnosed by endoscopy in adults. The efficacy of Omeprazole and Sodium Bicarbonate capsules used for longer than 8 weeks in patients with EE has not been established. If a patient does not respond to 8 weeks of treatment, an additional 4 weeks of treatment may be given. If there is recurrence of EE or GERD symptoms (e.g., heartburn), additional 4 to 8-week courses of Omeprazole and Sodium Bicarbonate capsules may be considered. maintenance of healing of EE due to acid-mediated GERD. Controlled studies do not extend beyond 12 months.

Important Administration Instructions Omeprazole and Sodium Bicarbonate is available as a capsule in 20 mg and 40 mg strengths of omeprazole for adult use. All recommended doses throughout the labeling are based upon omeprazole. The sodium content of Omeprazole and Sodium Bicarbonate capsules should be taken into consideration when prescribing this product [see Warnings and Precautions (5.3)]: Omeprazole and Sodium Bicarbonate capsule: each 20 mg and 40 mg capsule contains 1,100 mg (13 mEq) of sodium bicarbonate. The total content of sodium in each capsule is 304 mg. Due to the sodium bicarbonate content of Omeprazole and Sodium Bicarbonate capsules: Do not substitute two 20 mg Omeprazole and Sodium Bicarbonate capsules with one 40 mg Omeprazole and Sodium Bicarbonate capsule. 2.2 Dosage Regimen The recommended dosage regimen by indication in adults of Omeprazole and Sodium Bicarbonate capsules is summarized in Table 1. All recommended dosages are based upon omeprazole content. Table 1: Recommended Dosage Regimen of Omeprazole and Sodium Bicarbonate Capsules in Adults by Indication 1. Most patients heal within 4 weeks. Some patients may require an additional 4 weeks of therapy [see Clinical Studies (14.1)]. 2.The efficacy of Omeprazole and Sodium Bicarbonate capsules used for longer than 8 weeks in patients with EE has not been established. If a patient does not respond to 8 weeks of treatment, an additional 4 weeks of treatment may be given. If there is recurrence of EE or GERD symptoms (e.g., heartburn), additional 4 to 8-week courses of Omeprazole and Sodium Bicarbonate capsules may be considered. Indication Dosage of Omeprazole and Sodium Bicarbonate capsules Treatment Duration Treatment of Active Duodenal Ulcer 20 mg once daily 4 weeks1,2 Treatment of Active Benign Gastric Ulcer 40 mg once daily 4 to 8 weeks Treatment of Symptomatic GERD 20 mg once daily Up to 4 weeks Treatment of EE due to Acid-Mediated GERD 20 mg once daily 4 to 8 weeks2 Maintenance of Healing of EE due to Acid-Mediated GERD 20 mg once daily Controlled studies do not extend beyond 12 months. 2.3 Preparation and Administration Omeprazole and Sodium Bicarbonate Capsules Swallow capsules intact with water. Do not open the capsule and do not administer with liquids other than water. Take on an empty stomach at least one hour before a meal [see Clinical Pharmacology (12.3)].

Presence of Gastric Malignancy In adults, symptomatic response to therapy with Omeprazole and Sodium Bicarbonate capsules does not preclude the presence of gastric malignancy. Consider additional follow-up and diagnostic testing in adult patients who have a suboptimal response or an early symptomatic relapse after completing treatment with a proton pump inhibitor (PPI). In older patients, also consider an endoscopy. 5.2 Acute Tubulointerstitial Nephritis Acute tubulointerstitial nephritis (TIN) has been observed in patients taking PPIs and may occur at any point during PPI therapy. Patients may present with varying signs and symptoms from symptomatic hypersensitivity reactions to non-specific symptoms of decreased renal function (e.g., malaise, nausea and anorexia). In reported case series, some patients were diagnosed on biopsy and in the absence of extra-renal manifestations (e.g., fever, rash or arthralgia). Discontinue Omeprazole and Sodium Bicarbonate capsules and evaluate patients with suspected acute TIN [see Contraindications (4)]. 5.3 Sodium Bicarbonate Buffer Content Each 20 mg and 40 mg Omeprazole and Sodium Bicarbonate capsule contains 1,100 mg (13 mEq) of sodium bicarbonate. The total content of sodium in each capsule is 304 mg. Chronic administration of bicarbonate with calcium or milk can cause milk-alkali syndrome. Chronic use of sodium bicarbonate may lead to systemic alkalosis, and increased sodium intake can produce edema and weight gain. The sodium content of Omeprazole and Sodium Bicarbonate products should be taken into consideration when administering to patients on a sodium-restricted diet or those at risk for developing congestive heart failure. Avoid Omeprazole and Sodium Bicarbonate capsules in patients with Bartter’s syndrome, hypokalemia, hypocalcemia, and problems with acid-base balance. 5.4 Clostridium difficile-Associated Diarrhea Published observational studies suggest that PPI therapy like Omeprazole and Sodium Bicarbonate capsules may be associated with an increased risk of Clostridium difficile-associated diarrhea, especially in hospitalized patients. This diagnosis should be considered for diarrhea that does not improve [see Adverse Reactions (6.2)]. Patients should use the lowest dose and shortest duration of PPI therapy appropriate to the condition being treated. 5.5 Bone Fracture Several published observational studies suggest that proton pump inhibitor (PPI) therapy may be associated with an increased risk for osteoporosis-related fractures of the hip, wrist, or spine. The risk of fracture was increased in patients who received high-dose, defined as multiple daily doses, and long-term PPI therapy (a year or longer). Patients should use the lowest dose and shortest duration of PPI therapy appropriate to the condition being treated. Patients at risk for osteoporosis-related fractures should be managed according to the established treatment guidelines [see Dosage and Administration (2.2) and Adverse Reactions (6.2)]. 5.6 Severe Cutaneous Adverse Reactions Severe cutaneous adverse reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP) have been reported in association with the use of PPIs [see Adverse Reactions (6.2)]. Discontinue Omeprazole and Sodium Bicarbonate capsules at the first signs or symptoms of severe cutaneous adverse reactions or other signs of hypersensitivity and consider further evaluation. 5.7 Cutaneous and Systemic Lupus Erythematosus Cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE) have been reported in patients taking PPIs, including omeprazole. These events have occurred as both new onset and an exacerbation of existing autoimmune disease. The majority of PPI-induced lupus erythematosus cases were CLE. The most common form of CLE reported in patients treated with PPIs was subacute CLE (SCLE) and occurred within weeks to years after continuous drug therapy in patients ranging from infants to the elderly. Generally, histological findings were observed without organ involvement. Systemic lupus erythematosus (SLE) is less commonly reported than CLE in patients receiving PPIs. PPI associated SLE is usually milder than non-drug induced SLE. Onset of SLE typically occurred within days to years after initiating treatment in patients ranging from young adults to the elderly. The majority of patients presented with rash; however, arthralgia and cytopenia were also reported. Avoid administration of PPIs for longer than medically indicated. If signs or symptoms consistent with CLE or SLE are noted in patients receiving Omeprazole and Sodium Bicarbonate capsules, discontinue the drug and refer the patient to the appropriate specialist for evaluation. Most patients improve with discontinuation of the PPI alone in 4 to 12 weeks. Serological testing (e.g., ANA) may be positive and elevated serological test results may take longer to resolve than clinical manifestations. 5.8 Interaction with Clopidogrel Avoid concomitant use of Omeprazole and Sodium Bicarbonate capsules with clopidogrel. Clopidogrel is a prodrug. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. The metabolism of clopidogrel to its active metabolite can be impaired by use with concomitant medications, such as omeprazole, that interfere with CYP2C19 activity. Concomitant use of clopidogrel with 80 mg omeprazole reduces the pharmacological activity of clopidogrel, even when administered 12 hours apart. When using Omeprazole and Sodium Bicarbonate capsules, consider alternative anti-platelet therapy [see Drug Interactions (7) and Clinical Pharmacology (12.3)]. 5.9 Cyanocobalamin (Vitamin B-12) Deficiency Daily treatment with any acid-suppressing medications over a long period of time (e.g., longer than 3 years) may lead to malabsorption of cyanocobalamin (vitamin B-12) caused by hypo- or achlorhydria. Rare reports of cyanocobalamin deficiency occurring with acid-suppressing therapy have been reported in the literature. This diagnosis should be considered if clinical symptoms consistent with cyanocobalamin deficiency are observed in patients treated with Omeprazole and Sodium Bicarbonate capsules. 5.10 Hypomagnesemia and Mineral Metabolism Hypomagnesemia, symptomatic and asymptomatic, has been reported rarely in patients treated with PPIs for at least three months, in most cases after a year of therapy. Serious adverse events include tetany, arrhythmias, and seizures. Hypomagnesemia may lead to hypocalcemia and/or hypokalemia and may exacerbate underlying hypocalcemia in at-risk patients. In most patients, treatment of hypomagnesemia required magnesium replacement and discontinuation of the PPI. For patients expected to be on prolonged treatment or who take PPIs with medications such as digoxin or drugs that may cause hypomagnesemia (e.g., diuretics), health care professionals may consider monitoring magnesium levels prior to initiation of PPI treatment and periodically [see Adverse Reactions (6.2)]. Consider monitoring magnesium and calcium levels prior to initiation of Omeprazole and Sodium Bicarbonate capsules and periodically while on treatment in patients with a preexisting risk of hypocalcemia (e.g., hypoparathyroidism). Supplement with magnesium and/or calcium as necessary. If hypocalcemia is refractory to treatment, consider discontinuing the PPI. 5.11 Interaction with St. John's wort or Rifampin Drugs which induce CYP2C19 or CYP3A4 (such as St. John’s wort or rifampin) can substantially decrease omeprazole concentrations [see Drug Interactions (7)]. Avoid concomitant use of Omeprazole and Sodium Bicarbonate capsules with St. John’s wort or rifampin. 5.12 Interactions with Investigations for Neuroendocrine Tumors Serum chromogranin A (CgA) levels increase secondary to drug-induced decreases in gastric acidity. The increas

Omeprazole and Sodium Bicarbonate capsules are contraindicated in patients with known hypersensitivity to substituted benzimidazoles or to any components of the formulation. Hypersensitivity reactions may include anaphylaxis, anaphylactic shock, angioedema, bronchospasm, acute tubulointerstitial nephritis, and urticaria [see Warnings and Precautions (5.2), Adverse Reactions (6.2)]. Proton pump inhibitors (PPIs), including Omeprazole and Sodium Bicarbonate capsules, are contraindicated in patients receiving rilpivirine containing products[see Drug Interactions (7)].

Tables 6 and 7 include drugs with clinically important drug interactions and interaction with diagnostics when administered concomitantly with omeprazole and instructions for preventing or managing them. Consult the labeling of concomitantly used drugs to obtain further information about interactions with PPIs. Table 6: Clinically Relevant Interactions Affecting Drugs Co-Administered with Omeprazole and Interaction with Diagnostics Antiretrovirals Clinical Impact: The effect of PPIs on antiretroviral drugs is variable. The clinical importance and the mechanisms behind these interactions are not always known. Decreased exposure of some antiretroviral drugs (e.g., rilpivirine, atazanavir and nelfinavir) when used concomitantly with omeprazole may reduce antiviral effect and promote the development of drug resistance [see Clinical Pharmacology (12.3)]. Increased exposure of other antiretroviral drugs (e.g., saquinavir) when used concomitantly with omeprazole may increase toxicity [see Clinical Pharmacology (12.3)]. There are other antiretroviral drugs which do not result in clinically relevant interactions with omeprazole. Intervention: Rilpivirine-containing products: Concomitant use with Omeprazole and Sodium Bicarbonate capsules are contraindicated [see Contraindications (4)]. Atazanavir: Avoid concomitant use with Omeprazole and Sodium Bicarbonate capsules. See prescribing information for atazanavir for dosing information. Nelfinavir: Avoid concomitant use with Omeprazole and Sodium Bicarbonate capsules. See prescribing information for nelfinavir. Saquinavir: See the prescribing information for saquinavir for monitoring of potential saquinavir-related toxicities. Other antiretrovirals: See prescribing information for specific antiretroviral drugs. Warfarin Clinical Impact: Increased INR and prothrombin time in patients receiving PPIs, including omeprazole, and warfarin concomitantly. Increases in INR and prothrombin time may lead to abnormal bleeding and even death. Intervention: Monitor INR and prothrombin time and adjust the dose of warfarin, if needed, to maintain target INR range. Methotrexate Clinical Impact: Concomitant use of omeprazole with methotrexate (primarily at high dose) may elevate and prolong serum concentrations of methotrexate and/or its metabolite hydroxymethotrexate, possibly leading to methotrexate toxicities. No formal drug interaction studies of high-dose methotrexate with PPIs have been conducted [see Warnings and Precautions (5.12)]. Intervention: A temporary withdrawal of Omeprazole and Sodium Bicarbonate capsules may be considered in some patients receiving high-dose methotrexate. CYP2C19 Substrates (e.g., clopidogrel, citalopram, cilostazol, phenytoin, diazepam) Clopidogrel Clinical Impact: Concomitant use of omeprazole 80 mg results in reduced plasma concentrations of the active metabolite of clopidogrel and a reduction in platelet inhibition [see Clinical Pharmacology (12.3)]. There are no adequate combination studies of a lower dose of omeprazole or a higher dose of clopidogrel in comparison with the approved dose of clopidogrel. Intervention: Avoid concomitant use with Omeprazole and Sodium Bicarbonate capsules. Consider use of alternative anti-platelet therapy [see Warnings and Precautions (5.7)]. Citalopram Clinical Impact: Increased exposure of citalopram leading to an increased risk of QT prolongation [see Clinical Pharmacology (12.3)]. Intervention: Limit the dose of citalopram to a maximum of 20 mg per day. See prescribing information for citalopram. Cilostazol Clinical Impact: Increased exposure of one of the active metabolites of cilostazol (3,4-dihydro­ cilostazol) [see Clinical Pharmacology (12.3)]. Intervention: Reduce the dose of cilostazol to 50 mg twice daily. See prescribing information for cilostazol. Phenytoin Clinical Impact: Potential for increased exposure of phenytoin. Intervention: Monitor phenytoin serum concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See prescribing information for phenytoin. Diazepam Clinical Impact: Increased exposure of diazepam [see Clinical Pharmacology (12.3)]. Intervention: Monitor patients for increased sedation and reduce the dose of diazepam as needed. Digoxin Clinical Impact: Potential for increased exposure of digoxin [see Clinical Pharmacology (12.3)]. Intervention: Monitor digoxin concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See digoxin prescribing information. Drugs Dependent on Gastric pH for Absorption (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole) Clinical Impact: Omeprazole can reduce the absorption of other drugs due to its effect on reducing intragastric acidity. Intervention: Mycophenolate mofetil (MMF): Co-administration of omeprazole in healthy subjects and in transplant patients receiving MMF has been reported to reduce the exposure to the active metabolite, mycophenolic acid (MPA), possibly due to a decrease in MMF solubility at an increased gastric pH. The clinical relevance of reduced MPA exposure on organ rejection has not been established in transplant patients receiving Omeprazole and Sodium Bicarbonate capsules and MMF. Use Omeprazole and Sodium Bicarbonate capsules with caution in transplant patients receiving MMF [see Clinical Pharmacology (12.3)]. See the prescribing information for other drugs dependent on gastric pH for absorption. Tacrolimus Clinical Impact: Potential for increased exposure of tacrolimus, especially in transplant patients who are intermediate or poor metabolizers of CYP2C19. Intervention: Monitor tacrolimus whole blood concentrations. Dose adjustment may be needed to maintain therapeutic drug concentrations. See prescribing information for tacrolimus. Interactions with Investigations of Neuroendocrine Tumors Clinical Impact: Serum chromogranin A (CgA) levels increase secondary to PPI-induced decreases in gastric acidity. The increased CgA level may cause false positive results in diagnostic investigations for neuroendocrine tumors [see Warnings and Precautions (5.11) and Clinical Pharmacology (12.2)]. Intervention: Temporarily stop PRILOSEC treatment at least 14 days before assessing CgA levels and consider repeating the test if initial CgA levels are high. If serial tests are performed (e.g., for monitoring), the same commercial laboratory should be used for testing, as reference ranges between tests may vary. Interaction with Secretin Stimulation Test Clinical Impact: Hyper-response in gastrin secretion in response to secretin stimulation test, falsely suggesting gastrinoma. Intervention: Temporarily stop Omeprazole and Sodium Bicarbonate capsules treatment at least 14 days before assessing to allow gastrin levels to return to baseline [see Clinical Pharmacology (12.2)]. False Positive Urine Tests for THC Clinical Impact: There have been reports of false positive urine screening tests for tetrahydrocannabinol (THC) in patients receiving PPIs. Intervention: An alternative confirmatory method should be considered to verify positive results. Other Clinical Impact: There have been clinical reports of interactions with other drugs metabolized via the cytochrome P450 system (e.g., cyclosporine, disulfiram). Intervention: Monitor patients to determine if it is necessary to adjust the dosage of these other drugs when taken concomitantly with Omeprazole and Sodium Bicarbonate capsules. Table 7: Clinically Relevant Interactions Affecting Omeprazole When Co-Administered with Other Drugs CYP2C19 or CYP3A4 Inducers Clinical Impact: Decreased exposure of omeprazole when used concomitantly with strong inducers [see Clinical Pharmacology (12.3)]. Intervention: St. John’s wort, rifampin: Avoid concomitant use with Omeprazole and Sodium Bicarbonate capsules [see Warnings and Precautions (5.10)]. Ritonavir-containing products: See prescribing information for specific drugs. CYP2C19 or CYP3A4 Inhi

The following serious adverse reactions are described below and elsewhere in labeling: Acute Tubulointerstitial Nephritis [see Warnings and Precautions (5.2)] Clostridium difficile-Associated Diarrhea [see Warnings and Precautions (5.4)] Bone Fracture [see Warnings and Precautions (5.5)] Severe Cutaneous Adverse Reactions [see Warnings and Precautions (5.6)] Cutaneous and Systemic Lupus Erythematosus [see Warnings and Precautions (5.7)] Cyanocobalamin (Vitamin B-12) Deficiency [see Warnings and Precautions (5.9)] Hypomagnesemia and Mineral Metabolism [see Warnings and Precautions (5.10)] Fundic Gland Polyps [see Warnings and Precautions (5.14)] 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of Omeprazole and Sodium Bicarbonate capsules has been established, in part, based on oral studies of an oral delayed-release omeprazole product. Clinical Trials with Omeprazole In the U.S. clinical trial population of 465 adult patients, the adverse reactions summarized in Table 3 were reported to occur in 1% or more of patients on therapy with omeprazole. Table 3: Adverse Reactions Occurring in 1% or More of Adult Patients in US Clinical Trials of Omeprazole Therapy Omeprazole % (n = 465) Placebo % (n = 64) Ranitidine % (n = 195) Headache 7 6 8 Diarrhea 3 3 2 Abdominal Pain 2 3 3 Nausea 2 3 4 Upper Respiratory Infection (URI) 2 2 3 Dizziness 2 0 3 Vomiting 2 5 2 Rash 2 0 0 Constipation 1 0 0 Cough 1 0 2 Asthenia 1 2 2 Back Pain 1 0 1 Table 4 summarizes the adverse reactions that occurred in 1% or more of omeprazole-treated patients from international double-blind and open-label clinical trials in which 2,631 patients and subjects received omeprazole. Table 4: Adverse Reactions Occurring in 1% or More of Adult Patients in International Clinical Trials of Omeprazole Therapy Omeprazole % (n = 2631) Placebo % (n = 120) Abdominal Pain 5.2 3.3 Nausea 4.0 6.7 Diarrhea 3.7 2.5 Vomiting 3.2 10.0 Headache 2.9 2.5 Flatulence 2.7 5.8 Acid Regurgitation 1.9 3.3 Constipation 1.5 0.8 Asthenia 1.3 0.8 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of omeprazole and sodium bicarbonate. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Omeprazole Body as a Whole: Hypersensitivity reactions, including anaphylaxis, anaphylactic shock, angioedema, bronchospasm, urticaria (see also Skin below), fever, pain, fatigue, malaise, and systemic lupus erythematosus. Cardiovascular: Chest pain or angina, tachycardia, bradycardia, palpitation, elevated blood pressure, and peripheral edema. Gastrointestinal: Pancreatitis (some fatal), anorexia, irritable colon, flatulence, fecal discoloration, esophageal candidiasis, mucosal atrophy of the tongue, dry mouth, stomatitis, abdominal swelling and fundic gland polyps. Gastroduodenal carcinoids have been reported in patients with Zollinger-Ellison syndrome on long-term treatment with omeprazole. This finding is believed to be a manifestation of the underlying condition, which is known to be associated with such tumors. Hepatic: Mild and, rarely, marked elevations of liver function tests [ALT (SGPT), AST (SGOT), γ-glutamyl transpeptidase, alkaline phosphatase, and bilirubin (jaundice)]. In rare instances, overt liver disease has occurred, including hepatocellular, cholestatic, or mixed hepatitis, liver necrosis (some fatal), hepatic failure (some fatal), and hepatic encephalopathy. Infections and Infestations: Clostridium difficile-associated diarrhea. Metabolism and Nutritional Disorders: Hypomagnesemia, hypocalcemia, hypokalemia [see Warnings and Precautions (5.10)], hyponatremia, hypoglycemia, and weight gain. Musculoskeletal: Muscle cramps, myalgia, muscle weakness, joint pain, bone fracture, and leg pain. Nervous System/Psychiatric: Psychic disturbances including depression, agitation, aggression, hallucinations, confusion, insomnia, nervousness, tremors, apathy, somnolence, anxiety, dream abnormalities; vertigo; paresthesia; and hemifacial dysesthesia. Respiratory: Epistaxis, pharyngeal pain. Skin: Severe generalized skin reactions including TEN (some fatal), SJS, DRESS, AGEP, cutaneous lupus erythematosus and erythema multiforme (some severe); purpura and/or petechiae (some with rechallenge); skin inflammation, urticaria, angioedema, pruritus, photosensitivity, alopecia, dry skin, and hyperhidrosis. Special Senses: Tinnitus, taste perversion. Ocular: Blurred vision, ocular irritation, dry eye syndrome, optic atrophy, anterior ischemic optic neuropathy, optic neuritis, and double vision. Urogenital: Tubulointerstitial nephritis, urinary tract infection, microscopic pyuria, urinary frequency, elevated serum creatinine, proteinuria, hematuria, glycosuria, testicular pain, gynecomastia, and erectile dysfunction. Hematologic: Rare instances of pancytopenia, agranulocytosis (some fatal), thrombocytopenia, neutropenia, leukopenia, anemia, leukocytosis, and hemolytic anemia have been reported. Sodium Bicarbonate Metabolic alkalosis, seizures, and tetany.

Mechanism of Action Omeprazole belongs to a class of antisecretory compounds, the substituted benzimidazoles, that suppress gastric acid secretion by specific inhibition of the H+/K+ ATPase enzyme system at the secretory surface of the gastric parietal cell. Because this enzyme system is regarded as the acid (proton) pump within the gastric mucosa, omeprazole has been characterized as a gastric acidpump inhibitor, in that it blocks the final step of acid production. This effect is dose related and leads to inhibition of both basal and stimulated acid secretion irrespective of the stimulus. 12.2 Pharmacodynamics Antisecretory Activity Results from a pharmacokinetic/pharmacodynamic (PK/PD) study of the antisecretory effect of repeated once-daily dosing of 40 mg and 20 mg of ZEGERID for oral suspension in healthy subjects are shown in Table 8 below. Table 8: Effect of ZEGERID for Oral Suspension on Intragastric pH, Day 7 1. P < 0.05 20 mg vs. 40 mg Once-Daily Dosage of ZEGERID for Oral Suspension Parameter 40 mg omeprazole and 1,680 mg sodium bicarbonate (n = 24) 20 mg omeprazole and 1,680 mg sodium bicarbonate (n = 28) % Decrease from Baseline for Integrated Gastric Acidity (mmol•hr/L) 84% 82% Coefficient of Variation 20% 24% % Time Gastric pH >41 (Hours)1 77% (18.6 h) 51% (12.2 h) Coefficient of Variation 27% 43% Median pH 5.2 4.2 Coefficient of Variation 17% 37% Note: Values represent medians. All parameters were measured over a 24-hour period. Results from a separate PK/PD study of antisecretory effect on repeated once-daily dosing of 40 mg/1,100 mg and 20 mg/1,100 mg of Omeprazole and Sodium Bicarbonate capsules in healthy subjects show similar effects in general on the above three PD parameters as those for ZEGERID for oral suspension 40 mg/1,680 mg and 20 mg/1,680 mg, respectively. The antisecretory effect lasts longer than would be expected from the very short (1 hour) plasma half-life, apparently due to irreversible binding to the parietal H+/K+ ATPase enzyme. Enterochromaffin-like (ECL) Cell Effects Human gastric biopsy specimens have been obtained from more than 3000 patients treated with omeprazole in long-term clinical trials. The incidence of ECL cell hyperplasia in these studies increased with time; however, no case of ECL cell carcinoids, dysplasia, or neoplasia has been found in these patients. These studies are of insufficient duration and size to rule out the possible influence of long-term administration of omeprazole on the development of any premalignant or malignant conditions. Serum Gastrin Effects In studies involving more than 200 patients, serum gastrin levels increased during the first 1 to 2 weeks of once-daily administration of therapeutic doses of omeprazole in parallel with inhibition of acid secretion. No further increase in serum gastrin occurred with continued treatment. In comparison with histamine H2-receptor antagonists, the median increases produced by 20 mg doses of omeprazole were higher (1.3 to 3.6-fold vs. 1.1- to 1.8-fold increase). Gastrin values returned to pretreatment levels, usually within 1 to 2 weeks after discontinuation of therapy. Increased gastrin causes enterochromaffin-like cell hyperplasia and increased serum Chromogranin A (CgA) levels. The increased CgA levels may cause false positive results in diagnostic investigations for neuroendocrine tumors [see Warnings and Precautions (5.11)]. Other Effects Systemic effects of omeprazole in the central nervous system (CNS), cardiovascular and respiratory systems have not been found to date. Omeprazole, given in oral doses of 30 or 40 mg for 2 to 4 weeks, had no effect on thyroid function, carbohydrate metabolism, or circulating levels of parathyroid hormone, cortisol, estradiol, testosterone, prolactin, cholecystokinin or secretin. No effect on gastric emptying of the solid and liquid components of a test meal was demonstrated after a single dose of omeprazole 90 mg. In healthy subjects, a single intravenous dose of omeprazole (0.35 mg/kg) had no effect on intrinsic factor secretion. No systematic dose-dependent effect has been observed on basal or stimulated pepsin output in humans. However, when intragastric pH is maintained at 4.0 or above, basal pepsin output is low, and pepsin activity is decreased. As do other agents that elevate intragastric pH, omeprazole administered for 14 days in healthy subjects produced a significant increase in the intragastric concentrations of viable bacteria. The pattern of the bacterial species was unchanged from that commonly found in saliva. All changes resolved within three days of stopping treatment. The course of Barrett's esophagus in 106 patients was evaluated in a U.S. double-blind controlled study of omeprazole 40 mg twice daily for 12 months followed by 20 mg twice daily for 12 months or ranitidine 300 mg twice daily for 24 months. No clinically significant impact on Barrett's mucosa by antisecretory therapy was observed. Although neosquamous epithelium developed during antisecretory therapy, complete elimination of Barrett's mucosa was not achieved. No significant difference was observed between treatment groups in development of dysplasia in Barrett's mucosa, and no patient developed esophageal carcinoma during treatment. No significant differences between treatment groups were observed in development of ECL cell hyperplasia, corpus atrophic gastritis, corpus intestinal metaplasia, or colon polyps exceeding 3 mm in diameter. 12.3 Pharmacokinetics Absorption Table 9 show the systemic exposures and the time reach peak concentration (Tmax) of omeprazole in healthy subjects following administration of Omeprazole and Sodium Bicarbonate capsules, on an empty stomach one hour prior to a meal. Table 9: Arithmetic Mean (CV%) of the Systemic Exposures (Cmax, AUC) and Tmax of Omeprazole after a Single Oral Dose and Multiple Once-Daily Doses of Omeprazole and Sodium Bicarbonate Capsules n.a.: not applicable *AUC0-24h was used on Day 7 20 mg Omeprazole and Sodium Bicarbonate capsules 40 mg Omeprazole and Sodium Bicarbonate capsules Day 1 Day 7 % Change (Day 7/ Day 1) Day 1 Day 7 % Change (Day 7/ Day 1) Cmax (ng/mL) 498.1 (50.9) 679.8 (44.0) 36 1154 (53.0) 1526 (48.7) 32 Tmax (hr) [min – max] 0.61 [0.25-1.5] 0.82 [0.25-1.5] n.a. 0.56 [0.25-1.5] 0.97 [0.25-3.5] n.a. AUC0-inf* (ng•hr/mL) 509.7 (60.5) 1029 (67.9) 102 1882 (120) 3866 (83.3) 105 Following single or repeated once-daily dosing, peak plasma concentrations (Cmax) of omeprazole from Omeprazole and Sodium Bicarbonate capsules were approximately proportional from 20 to 40 mg doses. A greater than dose proportional increase in mean steady-state AUC (more than three-fold increase on Day 7) was observed when doubling the dose to 40 mg. The bioavailability of omeprazole from Omeprazole and Sodium Bicarbonate capsules increases upon repeated administration. The percent changes in Cmax and AUC between steady-state (Day 7) and single dose (Day 1) indicate omeprazole is a time-dependent autoinhibitor of CYP2C19. When Omeprazole and Sodium Bicarbonate capsule 40 mg is administered one hour after a meal, the omeprazole AUC is reduced by approximately 27% and 22%, respectively, relative to administration one hour prior to a meal [see Dosage and Administration (2.3)]. Distribution Omeprazole is bound to plasma proteins. Protein binding is approximately 95%. Elimination Metabolism Omeprazole is extensively metabolized by the cytochrome P450 (CYP) enzyme system. The major part of its metabolism is dependent on the polymorphically expressed CYP2C19 [see Clinical Pharmacology (12.5)], responsible for the formation of hydroxyomeprazole, the major metabolite in plasma. The remaining part is dependent on another specific isoform, CYP3A4, responsible for the formation of omeprazole sulphone. The mean plasma omeprazole half-life following administration of Omeprazole and Sodium Bicarbonate capsule in healthy subjects is approximately 1 hour (range 0.4 to 4.2 hours), and the total body