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Amoxicillin / Clarithromycin / Lansoprazole Dosage

Applies to the following strength(s): 500 mg-500 mg-30 mg

The information at is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for Helicobacter pylori Infection

1000 mg amoxicillin, 500 mg clarithromycin, and 30 mg lansoprazole, orally two times daily (morning and evening) for 10 to 14 days.

Renal Dose Adjustments

Amoxicillin/clarithromycin/lansoprazole (Prevpac) is not recommended in patients with CrCl less than 30 mL/min.

Liver Dose Adjustments

In patients with severe hepatic disease, a reduction in the dose of lansoprazole should be considered.


Amoxicillin/clarithromycin/lansoprazole is contraindicated for use in patients who are receiving drugs primarily metabolized in the liver by the CYP3A isoform. Concomitant administration with cisapride, pimozide, astemizole, terfenadine, ergotamine or dihydroergotamine is contraindicated. There have been postmarketing reports of drug interactions when clarithromycin and/or erythromycin are administered concomitantly with cisapride, pimozide, astemizole, or terfenadine resulting in cardiac arrhythmias (QT prolongation, ventricular tachycardia, ventricular fibrillation, and torsades de pointes). Fatalities have been reported.

Serious and occasionally fatal hypersensitivity reactions have been reported in patients on penicillin therapy. Before initiating amoxicillin therapy, a careful evaluation should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins, or other allergens. The drug should be discontinued immediately at the first appearance of a skin rash or other signs of hypersensitivity. Severe, acute hypersensitivity reactions may require treatment with epinephrine and other resuscitative measures including oxygen, intravenous fluids, antihistamines, corticosteroids, cardiovascular support and airway management as clinically indicated.

Proton pump inhibitors may interfere with the detection of H pylori by the urea breath test. Therefore, testing for H pylori with the urea breath test is not recommended in patients who have received proton pump inhibitors in the preceding two weeks.

Clarithromycin should not be used in pregnant women except in clinical circumstances where no alternative therapy is appropriate. If pregnancy occurs while taking clarithromycin, the patient should be apprised of the potential hazard to the fetus.

Pseudomembranous colitis has been reported with all antibiotics and may potentially be life-threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhea while receiving amoxicillin and clarithromycin therapy. Mild cases generally improve with discontinuation of the drug, while severe cases may require supportive therapy and treatment with an antimicrobial agent effective against Clostridium difficile.

Clarithromycin is primarily excreted via the liver and kidneys. In patients with hepatic impairment and normal renal function, clarithromycin may be administered without dosage adjustment. However, decreased dosage or prolonged dosing intervals may be appropriate in the presence of severe renal impairment with or without coexisting hepatic impairment.

The possibility of developing a superinfection with mycotic or bacterial pathogens should be kept in mind. If superinfections occur, amoxicillin/clarithromycin/lansoprazole should be discontinued and appropriate therapy started.

Symptomatic response to therapy with amoxicillin/clarithromycin/lansoprazole does not preclude the presence of gastric malignancy.

Proton pump inhibitors should be used with caution in patients who have hypocalcemia or hypoparathyroidism.

Calcium absorption is decreased in patients with achlorhydria.

Proton pump inhibitors could contribute to the development of vitamin B12 deficiency with prolonged use.


Amoxicillin is dialyzable. Clarithromycin and lansoprazole are not dialyzable.