Phenytoin
Trade names: Epanutin, Dilantin
Class: anticonvulsant , antiarrhythmic
Pregnancy:
(Category D) Action:
acts in the motor cortex of the brain to reduce the spread
of electrical
discharges
from the rapidly firing epileptic foci in this area. Also activity of centers
in the brain stem responsible for the tonic phase of grand mal seizures
Uses:
• Chronic epilepsy.
• Premature ventricular contractions.
• Tachycardia.
Dose:
by mouth, initially 3–4 mg/kg daily or
150–300 mg daily (as a single dose or in 2 divided doses) increased gradually
as necessary; usual dose 200–500 mg daily; CHILD initially 5 mg/kg daily in 2
divided doses, usual dose range 4–8 mg/kg daily (max. 300 mg) By intravenous
injection : status epilepticus, 15 mg/kg at a rate not exceeding 50 mg per
minute, as a loading dose; maintenance doses of about 100 mg should be given
thereafter at intervals of every 6–8 hours; rate and dose reduced according to
weight; CHILD 15 mg/kg
as a loading dose (neonate 15–20 mg/kg
at rate of 1–3 mg/kg/minute) Prophylaxis of convulsion : 4-7 mg/kg/day, divided
into 2 doses.
Ventricular arrhythmias , by
intravenous injection via caval catheter " Central Line", 3.5–5 mg/kg
at a rate not exceeding 50 mg/minute, with blood pressure and ECG monitoring;
repeat once if necessary.
Contraindications:
• Hypersensitivity.
Side effects:
§
Drowsiness,
§
ataxia,
§
dizziness,
§
measles-like rash,
§
gingival hyperplasia,
§ Hirsutism (excessive hair growth) ,and § hypoglycemia.
N.B :
Rapid I.V. administration Hypotension &
arrhythmia.
Nursing
considerations:
• I.V. phenytoin may forms a precipitate, so flush tubing by
saline (not dextrose) before & after administration.
• Assess for hypersensitivity.
• If a pregnant woman takes this drug, tell her not to breast-feed her baby.
• Obtain
liver & kidney function studies.
• Monitor serum drug levels on a routine basis.
• During I.V. therapy, monitor B.P. for signs of hypotension . Take e food to minimize GI
upset.
• If the patient is diabetic, monitor for signs of hypoglycemia.
• Oral hygiene to minimize bleeding from the gum.
• Report any excessive growth of hair.
