Medications that may interact with omeprazole include certain antibiotics; anticoagulants, such as warfarin; atazanavir; benzodiazepines, such as Valium; and cyclosporine. Pletal, Plavix, digoxin, diuretics and Antabuse may also interact with omeprazole, states MedlinePlus. Other medications, including tacrolimus, iron supplements, ketoconazole, methotrexate and phenytoin, may cause problems when taken with omeprazole.
To avoid potential drug interactions, patients should inform their doctors or pharmacists of all medications they are taking, including prescription and over-the-counter medications, vitamins, supplements and herbal products, advises MedlinePlus. Even if an interaction exists between omeprazole and a specific medication, sometimes doctors instruct patients to continue both medications. These patients may require dosage adjustments and close monitoring for unwanted side effects.
Omeprazole is a proton-pump inhibitor, which works by decreasing the amount of acid produced by the stomach. It is typically used to treat ulcers, gastroesophageal reflux disease and frequent heartburn, according to MedlinePlus. Side effects that may occur while taking omeprazole include constipation, gas, nausea, vomiting and headache. It is necessary to report these side effects to a doctor only if they are severe or persistent. Severe side effects, including difficulty breathing or swallowing, dizziness, seizures, watery stools, and swelling of the face, lips, throat or tongue, warrant immediate medical attention.