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:
When these two medicines are taken together, valproic acid may interfere with your phenytoin and phenytoin may interfere with your valproic acid.
What might happen:
Your blood levels of phenytoin may increase and your blood levels of valproic acid may decrease.
What you should do about this interaction:
If you experience a seizure, loss of coordination, constant unintentional eye movements, drowsiness, or mental changes, contact your doctor. It may be necessary to adjust the dose of either medicine.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this drug interaction and may be monitoring you for it. Do not stop, start, or change the dosage of any medicine before checking with them first.
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