Omeprazole Antacids

Dofetilide is not administered with cimetidine because dofetilide plasma levels may be increased by as much as 50%. When treatment for gastric disorders is necessary, patients receiving dofetilide should take omeprazole ranitidine, or antacids as an alternative to cimetidine. 

Antacid/alginic acid (Gaviscon) 2 tablets or 1 5 mL after meals and at bedtime AND/OR C. Patient-directed therapy Over-the-counter H2RAs (each taken up to twice daily) - Cimetidine 200 mg - Lamotidine 1 0 mg - Nizatidine 75 mg - Ranitidine 75 mg OR Over-the-counter PPI (taken once daily) - Omeprazole 20 mg agent. 

Drug therapy, if necessary, may be initiated with aluminum, calcium, or magnesium antacids sucralfate or cimetidine or ranitidine. Lansoprazole, omeprazole, and metoclopramide are also options if the patient does not respond to histamine-2 receptor blockers. 

Drugs that may affect HMG-CoA reductase inhibitors include alcohol, amiodarone, antacids, azole antifungals, bile acid sequestrants, cimetidine, cyclosporine, diltiazem, erythromycin, gemfibrozil, isradipine, nefazodone, niacin, nicotinic acid, omeprazole, phenytoin, propranolol, protease inhibitors, ranitidine, rifampin, St. John s wort, and verapamil. 

OMEPRAZOLE Take before eating. Do not open, crush, or chew the capsule swallow whole. In clinical trials, antacids were used concomitantly with omeprazole. 

Agents in this class are omeprazole, lansoprazole, pantoprazole and rabeprazole. Esomeprazole is the S-enantiomer of omeprazole. After ingestion of gastric acid resistant formulations they are rapidly and more or less completely absorbed. Bioavailability may be reduced if administered with food or antacids. Elimination is via metabolism in the liver and the renal excretion of inactive metabolites. The elimination half-live is very variable, however, as explained above, not related to the duration of action. 

Atazanavir PI2 400 mg daily or 300 mg daily with ritonavir 100 daily. Adjust dose in hepatic insufficiency Take with food. Separate dosing from ddl or antacids by 1 h. Separate dosing from cimetidine and other acid-reducing agents by 12 h Nausea, vomiting, diarrhea, abdominal pain, headache, peripheral neuropathy, skin rash, indirect hyperbilirubinemia, prolonged PR and/or QTC interval See footnote 4 for contraindicated medications. Also avoid indinavir, irinotecan, and omeprazole. Avoid in severe hepatic insufficiency... 

Drug Interactions Gemfibrozil Niacin Erythromycin Cholestyramine Digoxin Cimetidine/ranitidine/ omeprazole Rifampicin Warfarin Itraconazole Gemfibrozil Niacin Erythromycin Propranolol Digoxin Warfarin Antacids Colestipol Digoxin Erythromycin Oral contraceptives Fibrates Niacin Azole antifungals... 

Gastrointestinal drugs. Avoid cimetidine and omeprazole which inhibit the clearance of R warfarin, and sucralfate which may impair its absorption. Ranitidine may be used but INR should be checked if the dose is high. Most antacids are safe. 

Cederberg C, Andersson T, Skanberg 11989 Omeprazole pharmacokinetics and metabolism in man. Scandinavian Journal of Gastroenterology Supplement 166 33-42 Clark C K, Merritt A M, Burrow J A et al 1996 Effect of an aluminum-magnesium hydroxide antacid and BSS on gastric pH in horses. Journal of the American Veterinary Medical Association 208 1687-1691 Clarke L L, Argenzio R A, Roberts M C 1990 Effect of meal feeding on plasma volume and urinary electrolyte clearance in ponies. American Journal of Veterinary Research 51 571-576... 

The coadministration of medications with EN can result in alterations in bioavailability and/or changes in the desired pharmacologic effects of several medications, including phenytoin, warfarin, selected antibiotics, antacids, and omeprazole. 

Atomoxetine did not aiter desipramine pharmacokinetics and wouid therefore not be expected to affect other substrates of CYP2D6. Atomoxetine did not aiter midazolam pharmacokinetics and wouid therefore not be expected to affect other substrates of CYP3A4. Antacids and omeprazole do not alter atomoxetine bioavaiiabiiity. 

Vincent J, Gardner MJ, Baris B, Willavize SA. Concurrent adm inistration of omeprazole and antacid does not alter the pharmacokinetics and phaim acody nam ic of dofetilide in healtiiy suh-iects. ClinPhamacolTher( 996) 59,182. 

An established interaction. Because of the likely increased risk of torsade de pointes, the manufacturer contraindicates the use of cimetidine in patients on dofetilide. This would seem to be a prudent precaution. This applies equally to cimetidine at over-the-counter doses, and patients on dofetilide should be warned to avoid this. No special precautions appear to be necessary with ranitidine. Note that omeprazole , (p.256) and antacids , (p.254) also appear not to interact with dofetilide. 

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