Omeprazole

1 INDICATIONS AND USAGE Omeprazole is a proton pump inhibitor (PPI) indicated for the: • Treatment of active duodenal ulcer in adults (1.1) • Eradication of Helicobacter pylori to reduce the risk of duodenal ulcer recurrence in adults (1.2) • Treatment of active benign gastric ulcer in adults (1.3) • Treatment of symptomatic gastroesophageal reflux disease (GERD) in patients 2 years of age and older (1.4) • Maintenance of healing of EE due to acid-mediated GERD in patients 2 years of age and older (1.6) • Pathologic hypersecretory conditions in adults (1.7) 1.1 Treatment of Active Duodenal Ulcer Omeprazole delayed-release capsules are indicated for short-term treatment of active duodenal ulcer in adults. Most patients heal within four weeks. Some patients may require an additional four weeks of therapy. 1.2 Helicobacter pylori Eradication to Reduce the Risk of Duodenal Ulcer Recurrence Eradication of H. pylori has been shown to reduce the risk of duodenal ulcer recurrence. Triple Therapy Omeprazole delayed-release capsules in combination with clarithromycin and amoxicillin, are indicated for treatment of patients with H. pylori infection and duodenal ulcer disease (active or up to 1-year history) to eradicate H. pylori in adults. Dual Therapy Omeprazole delayed-release capsules in combination with clarithromycin are indicated for treatment of patients with H. pylori infection and duodenal ulcer disease to eradicate H. pylori in adults. Among patients who fail therapy, omeprazole delayed-release capsules with clarithromycin are more likely to be associated with the development of clarithromycin resistance as compared with triple therapy. In patients who fail therapy, susceptibility testing should be done. If resistance to clarithromycin is demonstrated or susceptibility testing is not possible, alternative antimicrobial therapy should be instituted [see Clinical Pharmacology (12.4) and the clarithromycin prescribing information, Microbiology section]. 1.3 Treatment of Active Benign Gastric Ulcer Omeprazole delayed-release capsules are indicated for short-term treatment (4 to 8 weeks) of active benign gastric ulcer in adults. 1.4 Treatment of Symptomatic Gastroesophageal Reflux Disease (GERD) Omeprazole delayed-release capsules are indicated for the treatment of heartburn and other symptoms associated with GERD for up to 4 weeks in patients 2 years of age and older. 1.5 Treatment of Erosive Esophagitis (EE) Due to Acid-Mediated GERD Pediatric Patients 2 Years of Age to Adults Omeprazole delayed-release capsules are indicated for the short-term treatment (4 to 8 weeks) of EE due to acid-mediated GERD that has been diagnosed by endoscopy in patients 2 years of age and older. The efficacy of omeprazole delayed-release 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 delayed-release capsules may be considered. 1.6 Maintenance of Healing of EE Due to Acid-Mediated GERD Omeprazole delayed-release capsules are indicated for the maintenance healing of EE due to acid-mediated GERD in patients 2 years of age and older. Controlled studies do not extend beyond 12 months. 1.7 Pathological Hypersecretory Conditions Omeprazole delayed-release capsules are indicated for the long-term treatment of pathological hypersecretory conditions (e.g., Zollinger-Ellison syndrome, multiple endocrine adenomas and systemic mastocytosis) in adults.

2 DOSAGE AND ADMINISTRATION Indication Recommended Adult (2.1) and Pediatric Dosage (2.2) Treatment of Active Duodenal Ulcer 20 mg once daily for 4 weeks; some patients may require an additional 4 weeks (2.1) H. pylori Eradication to Reduce the Risk of Duodenal Ulcer Recurrence Triple Therapy: Omeprazole delayed-release capsules Amoxicillin Clarithromycin 20 mg 1000 mg 500 mg Each drug twice daily for 10 days (2.1) * Dual Therapy: Omeprazole delayed-release capsules Clarithromycin 40 mg once daily for 14 days** 500 mg three times daily for 14 days (2.1) Active Benign Gastric Ulcer 40 mg once daily for 4 to 8 weeks (2.1) Symptomatic GERD 20 mg once daily for up to 4 weeks (2.1) See full prescribing information for weight based dosing in pediatric patients 2 years of age and older (2.2) EE due to Acid-Mediated GERD 20 mg once daily for 4 to 8 weeks (2.1) *** Maintenance of Healing of EE due to Acid-Mediated GERD 20 mg once daily (2.1) **** See full prescribing information for weight based dosing in pediatric patients 2 years of age and older (2.2) Pathological Hypersecretory Conditions Starting dose is 60 mg once daily (varies with individual patient, see full prescribing information) as long as clinically indicated (2.1) * if ulcer present, continue omeprazole delayed-release capsules 20 mg once daily for an additional 18 days. ** if ulcer present, continue omeprazole delayed-release capsules 20 mg once daily for an additional 14 days. *** an additional 4 weeks of treatment may be given if no response; if recurrence additional 4 to 8 week courses may be considered. **** studied for 12 months. Reduce the dosage to 10 mg once daily for patients with hepatic impairment (Child-Pugh Class A, B, or C) and Asian patients ( 8.6 , 8.7 ) 2.1 Recommended Adult Dosage Regimen by Indication Table 1 shows the recommended dosage of omeprazole delayed-release capsules in adult patients by indication. Table 1: Recommended Dosage Regimen of Omeprazole Delayed-Release Capsules in Adults by Indication Indication Dosage of Omeprazole Delayed-Release Capsules Treatment Duration Treatment of Active Duodenal Ulcer 20 mg once daily 4 weeks 1 Helicobacter pylori Eradication to Reduce the Risk of Duodenal Ulcer Recurrence Triple Therapy Omeprazole delayed-release capsules 20 mg Amoxicillin 1000 mg Clarithromycin 500 mg Take all three drugs twice daily 10 days In patients with an ulcer present at the time of initiation of therapy, continue omeprazole delayed-release capsules 20 mg once daily for an additional 18 days for ulcer healing and symptom relief. Dual Therapy Omeprazole delayed-release capsules 40 mg once daily Clarithromycin 500 mg three times daily 14 days In patients with an ulcer present at the time of initiation of therapy, an additional 14 days of omeprazole delayed-release capsules 20 mg once daily is recommended for ulcer healing and symptom relief. 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 weeks 2 Maintenance of Healing of EE due to Acid-Mediated GERD 20 mg once daily 3 Controlled studies do not extend beyond 12 months. Pathological Hypersecretory Conditions Starting dose is 60 mg once daily; adjust to patient needs Daily dosages of greater than 80 mg should be administered in divided doses. Dosages up to 120 mg three times daily have been administered. As long as clinically indicated. Some patients with Zollinger-Ellison syndrome have been treated continuously for more than 5 years. 1. Most patients heal within 4 weeks; some patients may require an additional 4 weeks of therapy to achieve healing 2. The efficacy of omeprazole delayed-release 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 delayed-release capsules may be considered. 3 . Dosage reduction to 10 mg once daily is recommended for patients with hepatic impairment (Child-Pugh Class A, B or C) and Asian patients when used for the maintenance of healing of EE [see Use in Specific Populations ( 8.6 , 8.7 ) and Clinical Pharmacology ( 12.3 , 12.5 ) ]. 2.2 Recommended Pediatric Dosage Regimen by Indication Table 2 shows the recommended dosage of omeprazole delayed-release capsules in pediatric patients by indication. Table 2: Recommended Dosage Regimen of Omeprazole Delayed-Release Capsules in Pediatric Patients by Indication Indication Omeprazole Delayed-Release Capsules Dosage Regimen and Duration Treatment of Symptomatic GERD Patient Age Weight-Based Dose (mg) Regimen and Duration 2 to 16 years 10 to less than 20 kg: 10 mg Once daily for up to 4 weeks 20 kg and greater: 20 mg Treatment of EE due to Acid-Mediated GERD 2 to 16 years 10 to less than 20 kg: 10 mg Once daily for 4 to 8 weeks 1 20 kg and greater: 20 mg Maintenance of Healing of EE due to Acid-Mediated GERD 2 to 16 years 10 to less than 20 kg: 10 mg Once daily. Controlled studies do not extend beyond 12 months 20 kg and greater: 20 mg 1. The efficacy of omeprazole delayed-release 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 delayed-release capsules may be considered. 2.3 Administration Instructions • Take omeprazole delayed-release capsules before meals. • Antacids may be used concomitantly with omeprazole delayed-release capsules. • Missed doses: If a dose is missed, administer as soon as possible. However, if the next scheduled dose is due, do not take the missed dose, and take the next dose on time. Do not take two doses at one time to make up for a missed dose. Omeprazole Delayed-Release Capsules • Swallow omeprazole delayed-release capsules whole; do not chew. • For patients unable to swallow an intact capsule, omeprazole delayed-release capsules can be opened and administered as follows: 1. Place one tablespoon of applesauce into a clean container (e.g., empty bowl). The applesauce used should not be hot and should be soft enough to be swallowed without chewing. 2. Open the capsule. 3. Carefully empty all of the pellets inside the capsule on the applesauce. 4. Mix the pellets with the applesauce. 5. Swallow applesauce and pellets immediately with a glass of cool water to ensure complete swallowing of the pellets. Do not chew or crush the pellets. Do not save the applesauce and pellets for future use.

6 ADVERSE REACTIONS 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 (5.3) ] • Bone Fracture [see Warnings and Precautions (5.4) ] • Cutaneous and Systemic Lupus Erythematosus [see Warnings and Precautions (5.6) ] • Cyanocobalamin (Vitamin B-12) Deficiency [see Warnings and Precautions (5.8) ] • Hypomagnesemia and Mineral Metabolism [see Warnings and Precautions (5.9) ] • Fundic Gland Polyps [seeWarnings and Precautions (5.13) ] Adults: Most common adverse reactions in adults (incidence ≥2%) are • Headache, abdominal pain, nausea, diarrhea, vomiting, and flatulence (6) Pediatric patients (2 to 16 years of age): • Safety profile similar to that in adults, except that respiratory system events and fever were the most frequently reported reactions in pediatric studies. (8.4) To report SUSPECTED ADVERSE REACTIONS, contact Dr. Reddy’s Laboratories Inc., at 1-888-375-3784 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience with Omeprazole Monotherapy 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 data described below reflects exposure to omeprazole delayed-release capsules in 3096 patients from worldwide clinical trials (465 patients from U.S. studies and 2,631 patients from international studies). Indications clinically studied in U.S. trials included duodenal ulcer, resistant ulcer, and Zollinger-Ellison syndrome. The international clinical trials were double blind and open-label in design. The most common adverse reactions reported (i.e., with an incidence rate ≥2%) from omeprazole-treated patients enrolled in these studies included headache (7%), abdominal pain (5%), nausea (4%), diarrhea (4%), vomiting (3%), and flatulence (3%). Additional adverse reactions that were reported with an incidence ≥1% included acid regurgitation (2%), upper respiratory infection (2%), constipation (2%), dizziness (2%), rash (2%), asthenia (1%), back pain (1%), and cough (1%). The clinical trial safety profile in patients greater than 65 years of age was similar to that in patients 65 years of age or less. The clinical trial safety profile in pediatric patients who received omeprazole delayed-release capsules was similar to that in adult patients. Unique to the pediatric population, however, adverse reactions of the respiratory system were frequently reported in the 2 to 16 year age group (19%). In addition, accidental injuries were frequently reported in the 2 to 16 year age group (4%) [see Use in Specific Populations (8.4)] . 6.2 Clinical Trials Experience with Omeprazole in Combination Therapy for H. pylori Eradication In clinical trials using either dual therapy with omeprazole and clarithromycin, or triple therapy with omeprazole, clarithromycin, and amoxicillin, no adverse reactions unique to these drug combinations were observed. Adverse reactions observed were limited to those previously reported with omeprazole, clarithromycin, or amoxicillin alone. Dual Therapy (omeprazole/clarithromycin) Adverse reactions observed in controlled clinical trials using combination therapy with omeprazole and clarithromycin (n = 346) that differed from those previously described for omeprazole alone were taste perversion (15%), tongue discoloration (2%), rhinitis (2%), pharyngitis (1%) and flu-syndrome (1%). (For more information on clarithromycin, refer to the clarithromycin prescribing information, Adverse Reactions section.) Triple Therapy (omeprazole/clarithromycin/amoxicillin) The most frequent adverse reactions observed in clinical trials using combination therapy with omeprazole, clarithromycin, and amoxicillin (n = 274) were diarrhea (14%), taste perversion (10%), and headache (7%). None of these occurred at a higher frequency than that reported by patients taking antimicrobial agents alone. (For more information on clarithromycin or amoxicillin, refer to the respective prescribing information, Adverse Reactions sections.) 6.3 Postmarketing Experience The following adverse reactions have been identified during post-approval use of omeprazole. Because these reactions are voluntarily reported from a population of uncertain size, it is not always possible to reliably estimate their actual frequency or establish a causal relationship to drug exposure. Body As a Whole: Hypersensitivity reactions including anaphylaxis, anaphylactic shock, angioedema, bronchospasm, interstitial nephritis, urticaria, (see also Skin below); fever; pain; fatigue; malaise; systemic lupus erythematosus Cardiovascular: Chest pain or angina, tachycardia, bradycardia, palpitations, elevated blood pressure, peripheral edema Endocrine: Gynecomastia Gastrointestinal: Pancreatitis (some fatal), anorexia, irritable colon, fecal discoloration, esophageal candidiasis, mucosal atrophy of the tongue, stomatitis, abdominal swelling, dry mouth, microscopic colitis, fundic gland polyps. Gastroduodenal carcinoids have been reported in patients with ZE 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: Liver disease including hepatic failure (some fatal), liver necrosis (some fatal), hepatic encephalopathy hepatocellular disease, cholestatic disease, mixed hepatitis, jaundice, and elevations of liver function tests [ALT, AST, GGT, alkaline phosphatase, and bilirubin] Infections and Infestations: Clostridium difficile-associated diarrhea Metabolism and Nutritional disorders: Hypoglycemia, hypomagnesemia, with or without hypocalcemia and/or hypokalemia, hyponatremia, weight gain [see Warnings and Precautions ( 5.9 )]. Musculoskeletal: Muscle weakness, myalgia, muscle cramps, joint pain, leg pain, bone fracture Nervous System/Psychiatric: Psychiatric and sleep disturbances including depression, agitation, aggression, hallucinations, confusion, insomnia, nervousness, apathy, somnolence, anxiety, and dream abnormalities; tremors, paresthesia; vertigo Respiratory: Epistaxis, pharyngeal pain Skin: Severe generalized skin reactions including toxic epidermal necrolysis (some fatal), Stevens-Johnson syndrome, cutaneous lupus erythematosus and erythema multiforme; photosensitivity; urticaria; rash; skin inflammation; pruritus; petechiae; purpura; alopecia; dry skin; hyperhidrosis Special Senses: Tinnitus, taste perversion Ocular: Optic atrophy, anterior ischemic optic neuropathy, optic neuritis, dry eye syndrome, ocular irritation, blurred vision, double vision Urogenital: Interstitial nephritis, hematuria, proteinuria, elevated serum creatinine, microscopic pyuria, urinary tract infection, glycosuria, urinary frequency, testicular pain, erectile dysfunction Hematologic: Agranulocytosis (some fatal), hemolytic anemia, pancytopenia, neutropenia, anemia, thrombocytopenia, leukopenia, leukocytosis

12.3 Pharmacokinetics Omeprazole is a time-dependent inhibitor of CYP2C19, resulting in autoinhibition and nonlinear pharmacokinetics. The systemic exposure increases in a more than dose proportional manner after multiple oral doses of omeprazole. Compared to the first dose, the systemic exposure (C max and AUC 0-24h ) at steady state following once a day dosing increased by 61% and 62%, respectively, compared to after the first dose for the 20 mg dose of omeprazole delayed-release capsules and increased by 118% and 175%, respectively, for the 40 mg dose of omeprazole delayed-release capsules. Absorption Omeprazole delayed-release capsules contain an enteric-coated granule formulation of omeprazole (because omeprazole is acid-labile), so that absorption of omeprazole begins only after the granules leave the stomach. Absorption is rapid, with peak plasma concentrations of omeprazole occurring within 0.5 to 3.5 hours. Peak plasma concentrations of omeprazole and AUC are approximately proportional to doses up to 40 mg, but because of a saturable first-pass effect, a greater than linear response in peak plasma concentration and AUC occurs with doses greater than 40 mg. Absolute bioavailability (compared with intravenous administration) is about 30 to 40% at doses of 20 to 40 mg, due in large part to presystemic metabolism. In healthy subjects the plasma half-life is 0.5 to 1 hour, and the total body clearance is 500 to 600 mL/min. The bioavailability of omeprazole increases slightly upon repeated administration of omeprazole delayed-release capsules. The systemic exposure (C max and AUC) are similar when a 40 mg omeprazole delayed-release capsule is administered with and without applesauce. However, administration of a 20 mg omeprazole delayed-release capsule with applesauce, results in a mean 25% reduction in C max without a significant change in AUC compared to administration without applesauce. The clinical relevance of this finding is unknown. Distribution 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, 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. Excretion Following single dose oral administration of a buffered solution of omeprazole, little if any unchanged drug was excreted in urine. The majority of the dose (about 77%) was eliminated in urine as at least six metabolites. Two were identified as hydroxyomeprazole and the corresponding carboxylic acid. The remainder of the dose was recoverable in feces. This implies a significant biliary excretion of the metabolites of omeprazole. Three metabolites have been identified in plasma the sulfide and sulfone derivatives of omeprazole, and hydroxyomeprazole. These metabolites have very little or no antisecretory activity. Combination Therapy with Antimicrobials Omeprazole 40 mg daily was given in combination with clarithromycin 500 mg every 8 hours to healthy adult male subjects. The steady state plasma concentrations of omeprazole were increased (C max , AUC 0-24 , and T 1/2 increases of 30%, 89% and 34% respectively) by the concomitant administration of clarithromycin. The observed increases in omeprazole plasma concentration were associated with the following pharmacological effects. The mean 24-hour gastric pH value was 5.2 when omeprazole was administered alone and 5.7 when co-administered with clarithromycin. The plasma concentrations of clarithromycin and 14-hydroxy-clarithromycin were increased by the concomitant administration of omeprazole. For clarithromycin, the mean C max was 10% greater, the mean C min was 27% greater, and the mean AUC 0-8 was 15% greater when clarithromycin was administered with omeprazole than when clarithromycin was administered alone. Similar results were seen for 14-hydroxy-clarithromycin, the mean C max was 45% greater, the mean C min was 57% greater, and the mean AUC 0-8 was 45% greater. Clarithromycin concentrations in the gastric tissue and mucus were also increased by concomitant administration of omeprazole. Table 6: Clarithromycin Tissue Concentrations 2 hours after Dose 1 Tissue Clarithromycin Clarithromycin + Omeprazole Antrum 10.48 ± 2.01 (n = 5) 19.96 ± 4.71 (n=5) Fundus 20.81 ± 7.64 (n = 5) 24.25 ± 6.37 (n= 5) Mucus 4.15 ± 7.74 (n = 4) 39.29 ± 32.79 (n=4) 1 mean ± SD (mcg/g) Specific Populations Age: Geriatric Population The elimination rate of omeprazole was somewhat decreased in the elderly, and bioavailability was increased. Omeprazole was 76% bioavailable when a single 40 mg oral dose of omeprazole (buffered solution) was administered to healthy elderly volunteers, versus 58% in young volunteers given the same dose. Nearly 70% of the dose was recovered in urine as metabolites of omeprazole and no unchanged drug was detected. The plasma clearance of omeprazole was 250 mL/min (about half that of young volunteers) and its plasma half-life averaged one hour, about twice that of young healthy volunteers. Age: Pediatric Population 2 to 16 Years of Age The pharmacokinetics of omeprazole have been investigated in pediatric patients 2 to 16 years of age: Table 7: Pharmacokinetic Parameters of Omeprazole Following Single and Repeated Oral Administration in Pediatric Populations Compared with Adults Single or Repeated Oral Dosing /Parameter Children 1 ≤ 20 kg 2 to 5 years Children 1 > 20 kg 6 to 16 years Adults 2 (mean 76 kg) 23 to 29 years(n=12) 10 mg 20 mg Single Dosing Cmax 3 (ng/mL) 288 (n=10) 495 (n=49) 668 AUC 3 (ng h/mL) 511 (n=7) 1140 (n=32) 1220 Repeated Dosing Cmax 3 (ng/mL) 539 (n=4) 851 (n=32) 1458 AUC 3 (ng h/mL) 1179 (n=2) 2276 (n=23) 3352 1 . Data from single and repeated dose studies. Doses of 10, 20 and 40 mg omeprazole as enteric-coated granules. 2 . Data from a single and repeated dose study. Doses of 10, 20 and 40 mg omeprazole as enteric-coated granules. 3 . Plasma concentration adjusted to an oral dose of 1 mg/kg. Following comparable mg/kg doses of omeprazole, younger children (2 to 5 years of age) have lower AUCs than children 6 to 16 years of age or adults; AUCs of the latter two groups did not differ [see Dosage and Administration (2) ]. Race/Ethnicity [See Clinical Pharmacology (12.5) ]. Renal Impairment In patients with chronic renal impairment (creatinine clearance between 10 and 62 mL/min/1.73 m2), the disposition of omeprazole was very similar to that in healthy subjects, although there was a slight increase in bioavailability. Because urinary excretion is a primary route of excretion of omeprazole metabolites, their elimination slowed in proportion to the decreased creatinine clearance. This increase in bioavailability is not considered to be clinically meaningful. Hepatic Impairment In patients with chronic hepatic disease classified as Child-Pugh Class A (n=3), B (n=4) and C (n=1), the bioavailability increased to approximately 100% compared to healthy subjects, reflecting decreased first-pass effect, and the plasma half-life of the drug increased to nearly 3 hours compared with the half-life in healthy subjects of 0.5 to 1 hour. Plasma clearance averaged 70 mL/min, compared with a value of 500 to 600 mL/min in healthy subjects [see Dosage and Administration (2.1) , Use in Specific Populations (8.6) ]. Drug Interaction Studies Effect of Omeprazole on Other Drugs Omeprazole is a time-dependent inhibitor of CYP2C19 and can increase the systemic exposure of co-administered drugs that are CYP2C19 substrates. In addition, administration of omeprazole increases intragastric pH and can alter the systemic exposure of certain drugs that exhibit pH-dependent solubility. Antiretrovirals For some antiretroviral drugs, such as rilpivirine, atazanavir and nelfinavir, decreased serum concentrations have been reported when given together with omeprazole [see Drug Interactions (7) ]. Rilpivirine: Following multiple doses of rilpivirine (150 mg, daily) and omeprazole (20 mg, daily), AUC was decreased by 40%, C max by 40%, and C min by 33% for rilpivirine. Nelfinavir: Following multiple doses of nelfinavir (1250 mg, twice daily) and omeprazole (40 mg daily), AUC was decreased by 36% and 92%, Cmax by 37% and 89% and Cmin by 39% and 75% respectively for nelfinavir and M8. Atazanavir: Following multiple doses of atazanavir (400 mg, daily) and omeprazole (40 mg, daily, 2 hours before atazanavir), AUC was decreased by 94%, C max by 96%, and C min by 95%. Saquinavir: Following multiple dosing of saquinavir/ritonavir (1000/100 mg) twice daily for 15 days with omeprazole 40 mg daily co-administered days 11 to 15. AUC was increased by 82%, Cmax by 75%, and Cmin by 106%. The mechanism behind this interaction is not fully elucidated. Therefore, clinical and laboratory monitoring for saquinavir toxicity is recommended during concurrent use with omeprazole. Clopidogrel In a crossover clinical study, 72 healthy subjects were administered clopidogrel (300 mg loading dose followed by 75 mg per day) alone and with omeprazole (80 mg at the same time as clopidogrel) for 5 days. The exposure to the active metabolite of clopidogrel was decreased by 46% (Day 1) and 42% (Day 5) when clopidogrel and omeprazole were administered together. Results from another crossover study in healthy subjects showed a similar pharmacokinetic interaction between clopidogrel (300 mg loading dose/75 mg daily maintenance dose) and omeprazole 80 mg daily when co-administered for 30 days. Exposure to the active metabolite of clopidogrel was reduced by 41% to 46% over this time period. In another study, 72 healthy subjects were given the same doses of clopidogrel and 80 mg omeprazole but the drugs were administered 12 hours apart; the results were similar, indicating that administering clopidogrel and omeprazole at different times does not prevent their interaction [see Warnings and Precautions (5.7) , Drug Interactions (7) ]. Mycophenolate Mofetil Administration of omeprazole 20 mg twice daily for 4 days and a single 1000 mg dose of MMF approximately one hour after the last dose of omeprazole to 12 healthy subjects in a cross-over study resulted in a 52% reduction in the C max and 23% reduction in the AUC of MPA [see Drug Interactions (7) ]. Cilostazol Omeprazole acts as an inhibitor of CYP2C19. Omeprazole, given in doses of 40 mg daily for one week to 20 healthy subjects in cross-over study, increased Cmax and AUC of cilostazol by 18% and 26% respectively. The Cmax and AUC of one of the active metabolites, 3,4- dihydro-cilostazol, which has 4 to 7 times the activity of cilostazol, were increased by 29% and 69%, respectively. Co-administration of cilostazol with omeprazole is expected to increase concentrations of cilostazol and the above mentioned active metabolite [see Drug Interactions (7) ]. Diazepam Concomitant administration of omeprazole 20 mg once daily and diazepam 0.1 mg/kg given intravenously resulted in 27% decrease in clearance and 36% increase in diazepam half-life [see Drug Interactions (7) ]. Digoxin Concomitant administration of omeprazole 20 mg once daily and digoxin in healthy subjects increased the bioavailability of digoxin by 10% (30% in two subjects) [see Drug Interactions (7) ]. Effect of Other Drugs on Omeprazole Voriconazole Concomitant administration of omeprazole and voriconazole (a combined inhibitor of CYP2C19 and CYP3A4) resulted in more than doubling of the omeprazole exposure. When voriconazole (400 mg every 12 hours for one day, followed by 200 mg once daily for 6 days) was given with omeprazole (40 mg once daily for 7 days) to healthy subjects, the steady-state Cmax and AUC0-24 of omeprazole significantly increased: an average of 2 times (90% CI: 1.8, 2.6) and 4 times (90% CI: 3.3, 4.4), respectively, as compared to when omeprazole was given without voriconazole [see Drug Interactions (7) ].