Phenytoin/Sulthiame Interactions
This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.
Medical warning:
Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Sulthiame may slow down how quickly your liver processes phenytoin.
What might happen:
The amount of phenytoin in your blood may increase and cause toxic effects, such as nausea, vomiting, confusion, dizziness, changes in vision, loss of coordination, or drowsiness.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Your doctor may want to check the amount of phenytoin in your blood more frequently when you start taking sulthiame and if you stop taking sulthiame. Let your healthcare professional know if you have any symptoms of phenytoin toxicity (nausea, vomiting, confusion, dizziness, changes in vision, loss of coordination, or drowsiness). Your doctor may need to change the dosage of your phenytoin.Your healthcare professionals 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.
- 1.Hansen JM, Kristensen M, Skovsted L. Sulthiame (Ospolot) as inhibitor of diphenylhydatoin metabolism. Epilepsia 1968 Mar;9(1):17-22.
- 2.Olesen OV, Jensen ON. Drug--interaction between sulthiame (Ospolot (R)) and phenytoin in the treatment of epilepsy. Dan Med Bull 1969 May; 16(5):154-8.
- 3.Houghton GW, Richens A. Proceedings: Inhibition of phenytoin metabolism by sulthiame. Br J Pharmacol 1973 Sep;49(1):157P-158P.
- 4.Houghton GW, Richens A. Phenytoin intoxication induced by sulthiame in epileptic patients. J Neurol Neurosurg Psychiatry 1974 Mar;37(3):275-81.
- 5.Dilantin (phenytoin sodium) US prescribing information. Pfizer, Inc. March, 2022.
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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.