Phenytoin, used to treat and prevent seizures, also has a relatively narrow therapeutic range. Documented reports describe elevated phenytoin levels when trazodone is added, which could increase phenytoin side effects like unsteadiness or vision changes. Anyone on phenytoin who starts trazodone should have levels monitored.
Trazodone and phenytoin
Similar to digoxin, case reports describe trazodone increasing phenytoin blood levels, which is relevant because phenytoin also has a narrow safety margin.
Editorially reviewed
Key points
- Phenytoin has a narrow therapeutic range
- Documented reports of elevated phenytoin levels with trazodone
- Monitor phenytoin levels when starting this combination
Not medical advice. Always tell your prescriber and pharmacist about every medication, supplement, and substance you use so they can check for interactions specific to your situation.