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omeprazole/amoxicillin/clarithromycin (Omeclamox-Pak)

 

Classes: PUD Combos; H pylori Agents

Dosing and uses of Omeclamox-Pak (omeprazole/amoxicillin/clarithromycin)

 

Adult dosage forms and strengths

omeprazole/amoxicillin/clarithromycin

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

 

Other Information

Combination therapy (omeprazole, amoxicillin, clarithromycin) indicated for the treatment of patients with H pylori infection and duodenal ulcer disease (active or 1-year history of a duodenal ulcer) to eradicate H pylori

To reduce development of drug-resistant bacteria and maintain efficacy of antibacterial drugs, use only to treat or prevent infections proven or strongly suspected to be caused by susceptible bacteria

 

Pediatric dosage forms and strengths

Safety and efficacy not established

 

Omeclamox-Pak (omeprazole/amoxicillin/clarithromycin) adverse (side) effects

>10%

Clarithromycin

  • GI effects, general (13%)

 

1-10%

Clarithromycin

  • 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

Omeprazole

  • 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%)

 

<1%

Clarithromycin

  • 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

Omeprazole

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

Amoxicillin

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

Clarithromycin

  • 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

See individual drug monographs for more information

 

Warnings

Contraindications

Coadministration with pimozide, ergotamine or dihydroergotamine

Omeprazole

  • • Hypersensitivity to omeprazole or other proton pump inhibitors

Amoxicillin

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

Clarithromycin

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

 

Cautions

Omeprazole

  • 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
  • Symptomatic response does not preclude concomitant underlying malignancy
  • Acute interstitial nephritis reported in patients taking PPIs
  • Concomitant use with colchicine has resulted in deaths, especially in elderly with renal insufficiency; monitor patients for clinical symptoms of colchicine toxicity

Amoxicillin

  • 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

Clarithromycin

  • 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 and lactation

 

Pregnancy category: C

Based on the pregnancy category for omeprazole and clarithromycin

No adequate and well-controlled studies in pregnant women; do not use clarithromycin or omeprazole in pregnant women except in circumstances in which no alternative therapy is appropriate

Lactation: Not recommended

 

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.

 

Pharmacology of Omeclamox-Pak (omeprazole/amoxicillin/clarithromycin)

Mechanism of action

Omeprazole

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

Amoxicillin

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

Clarithromycin

  • 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

 

Pharmacokinetics

Omeprazole

  • 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)

Amoxicillin

  • 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

Clarithromycin

  • 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