Phenytoin: Side Effects, Uses & Monitoring
Facts extracted from current FDA product labeling for Phenytoin. Educational only — not medical advice.
Reported adverse reactions
| Reaction | Highest frequency reported* |
|---|---|
| Nystagmus | 59.1% |
| Pruritus | 48.9% |
| Dizziness | 31.1% |
| Somnolence | 27.3% |
| Ataxia | 18.2% |
| Nausea | 13.6% |
| Hypotension | 9.1% |
| Vomiting | 9.1% |
| Tremor | 9.1% |
| Hypesthesia | 9.1% |
| Tinnitus | 9.1% |
| Amblyopia | 9.1% |
| Stupor | 7.7% |
| Ecchymosis | 7.3% |
| Accidental injury | 6.6% |
| Vasodilatation | 5.6% |
| Reflexes decreased | 4.9% |
| Headache | 4.5% |
| Dry mouth | 4.5% |
| Incoordination | 4.5% |
*Highest percentage across placebo-controlled trial tables summarized in current labeling.
Labeled uses
Fosphenytoin sodium injection, USP is indicated for the control of generalized tonic-clonic status epilepticus and prevention and treatment of seizures occurring during neurosurgery. Fosphenytoin can also be substituted, short-term, for oral phenytoin. Fosphenytoin should be used only when oral phenytoin administration is not possible. Fosphenytoin must not be given orally.
Source: FDA labeling via NIH DailyMed (set 87ff8a91…). Not affiliated with FDA or NIH.
Medical disclaimer: Always consult a qualified healthcare professional about any medication.