Omeprazole + Metronidazole + Clarithromycin

Indications

Omeprazole + Metronidazole + Clarithromycin is used for: H-pylori infection.

Adult Dose

Oral H.pylori infection Adult: As triple therapy: Omeprazole 20 mg combined w/ clarithromycin 250 mg and metronidazole 400 mg bid Each kit twice daily for 7-14 days.

Child Dose

Renal Dose

Administration

Contra Indications

Known hypersensitivity to any of its component.

Precautions

Serious and occasional hypersensitivity reactions have been reported in patients on amoxycillin therapy. Elderly patients may suffer from hepatic and renal impairment.

Pregnancy-Lactation

Interactions

Omeprazole: Increased risk of hypomagnesaemia w/ diuretics. May increase INR and prothrombin time w/ warfarin. Increased risk of digoxin-induced cardiotoxic effects. May increase plasma concentration benzodiazepines (e.g. diazepam), clarithromycin and methotrexate. Decreased absorption of itraconazole, ketoconazole, posaconazole, dasatinib, iron salts. May prolong elimination of diazepam, cilostazol, phenytoin and ciclosporin. May reduce the antiplatelet effect of clopidogrel. Potentially Fatal: May decrease plasma concentrations and pharmacological effects of rilpivirine, nelfinavir and atazanavir. Metronidazole: Concurrent use w/ disulfiram may produce psychotic reactions. May potentiate the effect of oral anticoagulants. May increase risk of lithium toxicity. May reduce the renal clearance resulting to increased toxicity of 5-fluorouracil. May increase serum levels of ciclosporin. May increase plasma levels of busulfan resulting to severe busulfan toxicity. Enhanced metabolism w/ phenobarbital and phenytoin resulting to decreased serum concentrations. Clarithromycin: Reduced efficacy w/ CYP3A inducers (e.g. phenytoin, carbamazepine). Strong inducers of CYP450 system (e.g. efavirenz, rifampicin) may accelerate metabolism, thus lower plasma levels of clarithromycin. Inhibition of metabolism w/ ritonavir. Torsades de pointes may result from concomitant quinidine or disopyramide. Increased phosphodiesterase inhibitor exposure w/ sildenafil, tadalafil or vardenafil. Increased risk of digoxin toxicity. Decreased concentration of zidovudine. Concomitant use w/ atazanavir, itraconazole or saquinavir may result to bi-directional drug interactions. Hypotension, bradyarrhythmias, and lactic acidosis may result when taken w/ verapamil. Increased risk of myopathy, including rhabdomyolysis w/ HMG-CoA reductase inhibitors. Increased risk of hypoglycaemia w/ oral hypoglycaemic drugs (e.g. pioglitazone) and insulin. Risk of serious haemorrhage and elevation of INR and prothrombin time w/ oral anticoagulants. Increased ototoxicity w/ aminoglycosides. Increased and prolonged sedation w/ triabenzodiazepines (e.g. midazolam). Potentially Fatal: Concurrent use w/ ergot alkaloids (e.g. ergotamine or dihydroergotamine) is associated w/ acute ergot toxicity characterised by vasospasm and ischaemia of the extremities. Concomitant use w/ astemizole, cisapride, pimozide and terfenadine may result in QT prolongation or ventricular cardiac arrhythmia.

Side Effects

Side effects of Omeprazole + Metronidazole + Clarithromycin : Nausea, vomiting, diarrhoea, dark stools, dry mouth, stomatitis, myalgia, confusion, headache, dizziness, vaginitis.

Mode of Action

Omeprazole is a substituted benzimidazole gastric antisecretory agent and is also known as PPI. It blocks the final step in gastric acid secretion by specific inhibition of H+/K+ ATPase enzyme system present on the secretory surface of the gastric parietal cell. Both basal and stimulated acid are inhibited. Metronidazole is converted to reduction products that interact w/ DNA to cause destruction of helical DNA structure and strand leading to a protein synthesis inhibition and cell death in susceptible organisms. It is active against most anaerobic protozoa, some gm+ve, gm-ve and facultative anaerobes. Clarithromycin inhibits protein synthesis in susceptible organisms by penetrating the cell wall and binding to 50S ribosomal subunits. It has activity against a variety of aerobic and anaerobic gm+ve and gm-ve bacteria.