Drug Interaction Report

Chronic use of drugs known as proton pump inhibitors including lansoprazole can sometimes cause hypomagnesemia (low blood levels of magnesium), and the risk may be further increased when combined with other medications that also have this effect such as panitumumab. In severe cases, hypomagnesemia can lead to irregular heart rhythm, palpitations, muscle spasm, tremor, and seizures. In children, abnormal heart rhythm may cause fatigue, upset stomach, dizziness, and lightheadedness. A dose adjustment or more frequent monitoring by the doctor may be required to safely use both medications. If you are using an over-the-counter proton pump inhibitor medication such as Prilosec OTC, Zegerid OTC or Prevacid 24 HR, you should follow the directions on the package carefully. Do not use the medication more frequently or for a longer period than recommended on the label unless otherwise prescribed by your doctor. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.