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fosphenytoin (fos-fen-i-toyn)



Therapeutic: anticonvulsants

Pharmacologic: hydantoin derivatives


Short-term (<5 day) parenteral management of generalized, convulsive status epilepticus when use of phenytoin is not feasible. Treatment and prevention of seizures during neurosurgery when use of phenytoin is not feasible.


Limits seizure propagation by altering ion transport. May also decrease synaptic transmission. Fosphenytoin is rapidly converted to phenytoin, which is responsible for its pharmacologic effects. Therapeutic Effects: Diminished seizure activity.

Adverse Reactions/Side Effects

CNS: dizziness, drowsiness, nystagmus, agitation, brain edema, headache, stupor, vertigo. EENT: amblyopia, deafness, diplopia, tinnitus. CV: hypotension (with rapid IV administration), tachycardia. GI: dry mouth, nausea, taste perversion, tongue disorder, vomiting. Derm: pruritus, rash, STEVENS-JOHNSON SYMDROME. MS: back pain. Neuro: ataxia, dysarthria, extrapyramidal syndrome, hypesthesia, incoordination, paresthesia, tremor. Misc: pelvic pain.


Examination and Evaluation

  • Monitor skin reactions (rash, itching/burning skin, hives, exfoliation, dermatitis). Notify physician immediately about because certain skin reactions may indicate serious hypersensitivity reactions (Stevens-Johnson syndrome).

  • Document the number, duration, and severity of seizures to help determine if this drug is effective in reducing seizure activity.

  • Assess dizziness and vertigo that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

  • Monitor drowsiness, confusion, agitation, stupor, or signs of brain edema (changes in mood and behavior, decreased consciousness, headache, lethargy, seizures, vomiting). Notify physician immediately of these signs.

  • Assess gait and motor function and document any signs of incoordination, ataxia, or other motor symptoms that might indicate extrapyramidal syndrome such as involuntary movements of the jaw, limbs, Parkinson-like symptoms, and other dystonias and dyskinesias. Report these signs to the physician.

  • Assess signs of tremor, paresthesia (numbness, tingling) or other changes in sensation. Perform objective tests, including electroneuromyography and sensory testing to document any drug-related neuropathic changes.

  • Assess blood pressure after IV administration and compare to normal values (See Appendix F). Report low blood pressure (hypotension), especially if patient experiences dizziness or syncope.

  • Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report rapid heart rate (tachycardia) or symptoms of other arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

  • Assess any back pain or pelvic pain to rule out musculoskeletal pathology; that is, try to determine if pain is drug induced rather than caused by anatomic or biomechanical problems.


  • Guard against falls and trauma (hip fractures, head injury, and so forth), especially if drowsiness, dizziness, or motor problems (ataxia, dyskinesias) affect gait and balance. Implement fall prevention strategies, especially if balance ...

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