omeprazole/amoxicillin/clarithromycin (Rx)

Brand and Other Names:Omeclamox-Pak
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Dosing & Uses


Dosing Forms & Strengths


capsule/capsule/tablet prepack

  • 20mg/500mg/500mg
  • Amoxicillin dose consists of two 500mg capsules (ie, 1000mg/dose)

Duodenal Ulcer

Indicated for eradication of H pylori to reduce risk of duodenal ulcer recurrence

Omeprazole 20 mg, amoxicillin 1000 mg, and clarithromycin 500 mg coadministered PO BID (morning and evening) for 10 days

Renal & Hepatic Impairment

Renal impairment: No dose adjustment necessary

Hepatic impairment: Avoid use

Safety and efficacy not established



Interaction Checker

and omeprazole/amoxicillin/clarithromycin

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            Adverse Effects



            • GI effects, general (13%)



            • Headache (2%)
            • Abdominal pain (2%)
            • Abnormal taste (3-7%)
            • Diarrhea (3-6%)
            • Dyspepsia (2%)
            • Heartburn (2%)
            • Nausea (3-6%)
            • Increased BUN (4%)
            • Increased PT (1%)
            • Vomiting (1%)
            • GI intolerance
            • Decrease WBC Rash


            • Acid regurgitation (1.9%)
            • Upper respiratory infection (1.9%)
            • Constipation (1.5%)
            • Dizziness (1.5%)
            • Rash (1.5%)
            • Asthenia (1.3%)
            • Back pain (1.1%)
            • Cough (1.1%)



            • QT prolongation
            • Neurology/Psychiatric: Anxiety, dizziness, hallucinations, manic behavior, neuromuscular blockade, psychosis, seizures
            • Gastrointestinal: Anorexia, glossitis, pancreatitis, jaundice, hepatitis/hepatic dysfunction, C difficile colitis
            • Laboratory: Bilirubin increased, elevated AST, LFTs, alkaline phosphate, serum creatinine; hypoglycemia, leukopenia, neutropenia, thrombocytopenia
            • Anaphylaxis, dyspnea, Stevens-Johnson syndrome

            Frequency Not Defined


            • Fracture of bone, osteoporosis-related
            • Hepatotoxicity (rare)
            • Hip fracture
            • Interstitial nephritis (rare)
            • Pancreatitis (rare)
            • Rhabdomyolysis
            • Toxic epidermal necrolysis (rare)


            • Headache
            • Rash
            • Diarrhea, nausea, vomiting
            • Anemia
            • AST/ALT elevation
            • Anaphylaxis
            • Candidiasis (mucocutaneous), pseudomembranous colitis, serum sickness


            • Torsade de pointes (rare)
            • Allergic reactions: urticaria & skin eruptions, leukocytoclastic vasculitis, toxic epidermal necrolysis, pruritus, rash
            • Transient CNS effects: psychosis, anxiety, behavioral changes, confusional states, depersonalization, disorientation, hallucinations, insomnia, nightmares, tinnitus, tremor, and vertigo
            • Hepatic failure
            • Stomatitis
            • Acute renal failure
            • Reversible hearing loss (hypoacusis)

            Postmarketing Reports

            Acute tubulointerstitial nephritis

            See individual drug monographs for more information




            Coadministration with pimozide, ergotamine or dihydroergotamine


            • • Hypersensitivity to omeprazole, benzimidazoles or other proton pump inhibitors


            • Allergy to penicillins, cephalosporins, imipenem
            • Infectious mononucleosis (relative)
            • Concomitant live bacterial vaccines


            • Clarithromycin/ranitidine bicitrate contraindicated in: severe renal impairment (CrCl<25 mL/min); history of acute porphyria



            • Liver disease may require dosage reduction
            • 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; particularly with prolonged (>1 yr), high-dose therapy
            • Hypomagnesemia may occur with prolonged use (ie, >1 year); adverse effects may result and include tetany, arrhythmias, or seizures; in 25% of cases reviewed, magnesium supplementation alone did not improve low serum magnesium levels and the PPI had to be discontinued
            • PPIs possibly associated with increased incidence of Clostridium difficile-associated diarrhea (CDAD); consider diagnosis of CDAD for patients taking PPIs with diarrhea that does not improve
            • Cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE) reported with PPIs; avoid using for longer than medically indicated; discontinue if signs or symptoms consistent with CLE or SLE are observed and refer patient to specialist
            • Symptomatic response does not preclude concomitant underlying malignancy
            • Acute tubulointerstitial nephritis (TIN) reported in patients taking PPIs; TIN 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 (eg, malaise, nausea, anorexia); in reported case series, some patients were diagnosed on biopsy and in the absence of extra-renal manifestations (eg, fever, rash or arthralgia); discontinue drug and evaluate patients with suspected acute TIN
            • Concomitant use with colchicine has resulted in deaths, especially in elderly with renal insufficiency; monitor patients for clinical symptoms of colchicine toxicity


            • Allergy to cephalosporins, carbapenems
            • Endocarditis prophylaxis: use only for high risk patients, per recent AHA Guidelines
            • High doses may cause false urine glucose test by some methods


            • Severe renal impairment
            • Do not refrigerate oral solution
            • Endocarditis prophylaxis: use only for high risk patients, per recent AHA Guidelines
            • Exacerbation of symptoms of myasthenia gravis and new onset of symptoms reported with clarithromycin; monitor patients for symptoms

            Pregnancy & Lactation


            Based on findings in animal studies for omeprazole and clarithromycin during pregnancy may cause fetal harm; therapy is not recommended for use in pregnant women except in clinical circumstances where no alternative therapy is appropriate; Ii therapy is administered during pregnancy, or if pregnancy occurs while receiving therapy, the patient should be apprised of the potential hazard to fetus; there are no adequate and well controlled studies of omeprazole, clarithromycin, or amoxicillin (used separately or together) in pregnant women

            Animal data

            • Clarithromycin demonstrated adverse developmental effects in four animal species at clinically relevant doses; omeprazole increased embryo-fetal loss in rabbits, but animal studies and multiple human studies do not show an increased risk for major malformations; there was no evidence of harm to fetus in mice and rats due to amoxicillin


            Based on limited human data, clarithromycin and its active metabolite 14-OH clarithromycin are present in human milk at less than 2% of maternal weight-adjusted dose; in a separate observational study, reported adverse effects on breast-fed children (rash, diarrhea, loss of appetite, somnolence) were comparable to amoxicillin

            No data are available to assess effects of clarithromycin or 14-OH clarithromycin on milk production

            Limited data from a single case report suggest omeprazole may be present in human milk; there are no clinical data on effects of omeprazole on breastfed infant or on milk production

            Data from a published clinical lactation study indicate that amoxicillin is present in human milk; published adverse effects with amoxicillin exposure in breast-fed infant include diarrhea; there are no data on effects of amoxicillin on milk production

            Development and health benefits of breastfeeding should be considered along with mother’s clinical need for omeprazole or clarithromycin or amoxicillin and any potential adverse effects on breast-fed child from clarithromycin or from underlying maternal condition.

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.



            Mechanism of Action


            • Proton pump inhibitor; binds to H+/K+-exchange ATPase (proton pump) in gastric parietal cells resulting in blocking acid secretion


            • Ampicillin derivative; elicits antibacterial effect by inhibiting biosynthesis of cell wall mucopeptide


            • Semisynthetic macrolide antibiotic that reversibly binds to P site of 50S ribosomal subunit of susceptible organisms and may inhibit RNA-dependent protein synthesis by stimulating dissociation of peptidyl t-RNA from ribosomes, causing bacterial growth inhibition



            • Half-Life: 0.5-1 hr; increases to 3 hr with hepatic impairment
            • Bioavailability: 30-40%
            • Peak Plasma Time: 0.5-3.5 hr
            • Protein Bound: 95-96%
            • Total Body Clearance: 500-600 mL/min
            • Metabolism: hepatic
            • Excretion: 77% urine; 16-19% feces (mainly in bile)


            • Half-Life: 1.5 hr
            • Absorption: 74-92%
            • Distribution: most body fluids and bone, CSF<1%
            • Peak Plasma Time: 1-2 hr
            • Protein Bound: 17-20%
            • Metabolism: hepatic
            • Excretion: urine


            • Half-Life: 3-7 hr
            • Peak Plasma Time: 2-4 hr
            • Absorption: highly stable in presence of gastric acid (unlike erythromycin); food delays but does not affect extent of absorption
            • Distribution: widely into most body tissues except CNS Metabolism: partially hepatic (P450 enzyme CYP3A4); converted to 14-OH clarithromycin (active metabolite)
            • Renal Clearance: approximates normal GFR
            • Excretion: primarily urine




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            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.