PHENYTOIN

(fen’i-toy-in)
Dilantin-125, Dilantin-30 Pediatric, Dilantin Infatab
PHENYTOIN SODIUM EXTENDED
Dilantin Kapseals
PHENYTOIN SODIUM PROMPT
Dilantin
Classifications:
central nervous system agent; anticonvulsant; hydantoin
Pregnancy Category: D

NURSING IMPLICATIONS

Assessment & Drug Effects

  • Continuously monitor vital signs and symptoms during IV infusion and for an hour afterward. Watch for respiratory depression. Constant observation and a cardiac monitor are necessary with older adults or patients with cardiac disease. Margin between toxic and therapeutic IV doses is relatively small.
  • Be aware of therapeutic serum concentration: 10–20 mcg/mL; toxic level: 30–50 mcg/mL; lethal level: 100 mcg/mL. Steady-state therapeutic levels are not achieved for at least 7–10 d.
  • Lab tests: Periodic serum phenytoin concentration; CBC with differential, platelet count, and Hct and Hgb; serum glucose, serum calcium, and serum magnesium; and liver funtion tests.
  • Observe patient closely for neurologic adverse effects following IV administration. Have on hand oxygen, atropine, vasopressor, assisted ventilation, seizure precaution equipment (mouth gag, nonmetal airway, suction apparatus).
  • Be aware that gingival hyperplasia appears most commonly in children and adolescents and never occurs in patients without teeth.
  • Make sure patients on prolonged therapy have adequate intake of vitamin D-containing foods and sufficient exposure to sunlight.
  • Monitor diabetics for loss of glycemic control.
  • Check periodically for decrease in serum calcium levels. Particularly susceptible: patients receiving other anticonvulsants concurrently, as well as those who are inactive, have limited exposure to sun, or whose dietary intake is inadequate.
  • Observe for symptoms of folic acid deficiency: neuropathy, mental dysfunction.
  • Be alert to symptoms of hypomagnesemia (see Appendix F); neuromuscular symptoms: tetany, positive Chvostek’s and Trousseau’s signs, seizures, tremors, ataxia, vertigo, nystagmus, muscular fasciculations.

Patient & Family Education

  • Be aware that drug may make urine pink or red to red-brown.
  • Report symptoms of fatigue, dry skin, deepening voice when receiving long-term therapy because phenytoin can unmask a low thyroid reserve.
  • Do not alter prescribed drug regimen. Stopping drug abruptly may precipitate seizures and status epilepticus.
  • Do not to request/accept change in drug brand when refilling prescription without consulting physician.
  • Understand the effects of alcohol: Alcohol intake may increase phenytoin serum levels, leading to phenytoin toxicity.
  • Discontinue drug immediately if a measles-like skin rash or jaundice appears and notify physician.
  • Be aware that influenza vaccine during phenytoin treatment may increase seizure activity. Understand that a change in dose may be necessary.
  • Do not breast feed while taking this drug.

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