Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Rifampin may speed how quickly your body processes valproic acid.
What might happen:
Your blood levels of valproic acid may decrease and it may not work as well.
What you should do about this interaction:
Let your healthcare professional (e.g. doctor or pharmacist) know that you are taking these medicines together. If different doctors have prescribed these two medicines make sure each of them knows you take this combination. If you experience decreased effectiveness of valproic acid (e.g. increase in seizures, migraine headaches, or unstable mood) contact your doctor. Your doctor may check valproic acid blood levels one or more times during the first 2 to 3 weeks you are on this combination. To keep your condition stable, the dose of valproic acid may need to be increased while you are also taking rifampin.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.Reference:1.Depakote (divalproex sodium) US prescribing information. AbbVie Inc. June, 2013.