Drug Interaction Report

Itraconazole may increase the blood levels and effects of erlotinib. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Let your doctor know if you experience severe or persistent diarrhea, nausea, vomiting, loss of appetite, skin rash, shortness of breath, cough, or fever while taking these medications, as these may be symptoms of excessive erlotinib effects. 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.

Food increases the absorption of itraconazole capsules but decreases the absorption of itraconazole oral solution. Capsules should be taken immediately after a full meal and the solution be taken on an empty stomach to ensure best results.

Erlotinib should be taken on an empty stomach at least 1 hour before or 2 hours after a meal and at the same time each day unless otherwise directed by your doctor. You should also avoid grapefruit and grapefruit juice while taking erlotinib. Food and grapefruit juice can increase the absorption of erlotinib from the gastrointestinal tract, which may lead to higher blood levels of the medication and possibly increased side effects. If you are a smoker, you should try to quit as soon as you can. Cigarette smoking can reduce the blood levels of erlotinib, which may make the medication less effective in treating your cancer. It is best to avoid smoking during erlotinib therapy. Talk to a healthcare professional if you have any questions or concerns. If you start smoking or undergo smoking cessation, your doctor may need to adjust your dose of erlotinib. 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.