Drug Interactions between dexamethasone / lidocaine and pazopanib

Do not consume grapefruit or grapefruit juice during treatment with PAZOPanib unless directed otherwise by your doctor. Grapefruit juice can increase the blood levels of PAZOPanib, which may lead to an increased risk of serious side effects such as liver damage, irregular heart rhythm, bleeding, high blood pressure, heart attack, and stroke. Taking PAZOPanib with food can also significantly increase its absorption and levels in the blood. Therefore, you should take PAZOPanib on an empty stomach, at least one hour before or two hours after eating. Call your doctor immediately if you develop fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. You should also seek immediate medical attention if you experience signs and symptoms that could indicate cardiovascular problems such as sudden dizziness; lightheadedness; fainting; fast or pounding heartbeats; chest pain or tightness; pain in your arms, back, neck, or jaw; shortness of breath; numbness or weakness on one side of your body; and slurred speech or difficulty speaking. 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.

Grapefruit juice may increase the blood levels of lidocaine, which may increase the risk of side effects such as low blood pressure, slow heart rate, irregular heart rhythm, difficulty breathing and convulsions. Cigarette smoking may reduce the blood levels of lidocaine, which may make the medication less effective. It is best to avoid smoking during lidocaine therapy. Consuming cruciferous vegetables (e.G., broccoli, brussels sprouts) may also reduce the blood levels of lidocaine. Talk to a healthcare professional if you have any questions or concerns. 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.

Consumer information for this interaction is not currently available.

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.