Adult Dosing
Generalized tonic-clonic (grand mal) and complex partial (psychomotor, temporal lobe) seizures
- Capsules
- Initial dose: 100 mg PO tid
- Loading dose: 1000 mg/day divide in 3 dose (400 mg. 300 mg, 300 mg); administer at 2 hr of interval
- 300 mg ER qd
- Suspension
- 5 mL PO tid
- May increase to 25 mL/day, if necessary
- Infatabs
- Initial dose: 100 mg PO tid
- Maintenance dose: 300-400 mg daily; increase to 600 mg/day, if necessary
- Note: Infatabs can be either chewed thoroughly before being swallowed or swallowed whole
Pediatric Dosing
Generalized tonic-clonic (grand mal) and complex partial (psychomotor, temporal lobe) seizures
- Capsule/Suspension/Tablet
- Initial dose; 5 mg/kg/day 2-3 equal divide dose; Max dose 300 mg
- Maintenance dose: 4-8 mg/kg
- >6 yrs and adolescents: May require minimum adult dose 300 mg/day
[Outline]
See Supplemental Patient Information
- Do not withdraw drug abruptly as this may precipitate status epilepticus; proceed slowly in case of dose reduction, discontinuation, or substitution of alternative antiepileptic drug
- Worsening of depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior may occur
- Advise families and caregivers to closely observe for emergence or worsening of sign/symptoms of depression, any unusual changes in mood or behavior, emergence of suicidality,or thoughts about self-harm and report such symptoms immediately to health care providers
- A relationship between phenytoin use and the development of lymphadenopathy (local or generalized) has been suggested. Lymph nodes involvement may occur with or without signs and symptoms resembling serum sickness (eg, fever, liver involvement, rash)
- Acute alcohol intake may increase phenytoin serum levels while chronic alcohol use may decrease serum levels
- Exacerbation of porphyria has been reported, caution should be exercised in patients suffering from this disease
- Increase in seizure frequency may occur during pregnancy because of altered phenytoin pharmacokinetics. Periodically measure plasma phenytoin concentration which may help to adjust the dose for management of pregnant women
- Patient should be apprised of the potential harm to the fetus by the usage of the drug during pregnancy or if the patient becomes pregnant while taking the drug
- Prenatal exposure to phenytoin may increase the risks for congenital and major malformations, minor anomalies, growth abnormalities, mental deficiencies and other adverse developmental outcomes. The risks and benefits of phenytoin should be weighed during pregnancy
- Life-threatening bleeding disorder related to decreased levels of vitamin K have occurred during postpartum period, administer vitamin K to mother before delivery and to the neonate after birth
- Patients with hepatic impairment, elderly patients, and those who are gravely ill may show early signs of toxicity
- Dilantin can cause rare, serious skin adverse events such as exfoliative dermatitis, Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. If the rash is exfoliative or of severe type, discontinue the drug.Alternate therapy must be preferred. If rash is of milder type, therapy may be resumed after the rash has completely disappeared. If rash reoccurs upon reinstitution of therapy, further phenytoin medication is contraindicated
- Hyperglycemia has been reported and may be caused by the inhibitory effects of phenytoin on insulin release. May also raise serum glucose levels in patients with diabetes
- Osteomalacia has been associated with phenytoin therapy and is thought to be caused by phenytoin's interference with vitamin D metabolism
- Not indicated for seizures due to hypoglycemic or other metabolic causes.Use appropriate diagnostic procedures
- If tonic-clonic (grand mal) and absence (petit mal) seizures are present combination therapy is needed as phenytoin is not effective against absence seizures
- Serum levels of phenytoin above the optimal range may produce confusional states or, rarely, irreversible cerebellar dysfunction
Cautions: Use cautiously in
- Thyroid disease
- HLA-B*1502-positive patients
Supplemental Patient Information
- Instruct patients to follow a good dental hygiene to minimize the development of gingival hyperplasia and its complications
- Advise patients to report promptly to their physicians if they develop skin rash
Pregnancy Category:D
Breastfeeding: As the levels of drug ingested by breastfed infants are small and usually cause no difficulties when used alone except for rare idiosyncratic reactions. Combination therapy with sedating anticonvulsants may result in infant sedation or withdrawal reactions. This information is based upon LactMed database (available at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT last accessed 21 February 2011). Manufacturer advises use with caution. As per manufacturer data it is not recommended because it appears in low concentration in human milk.
Pricing data from www.DrugStore.com in U.S.A.
- Phenytek 300 MG CAPS [Bottle] (MYLAN)
100 mg = $175
300 mg = $474.98 - Dilantin Infatabs 50 MG CHEW [Bottle] (PFIZER U.S.)
90 mg = $53.99
270 mg = $142.97 - Dilantin 125 MG/5ML SUSP [Bottle] (PFIZER U.S.)
237 5ml = $82.99
711 5ml = $220.97 - Dilantin 30 MG CAPS [Bottle] (PFIZER U.S.)
90 mg = $54.99
270 mg = $164.96 - Dilantin 100 MG CAPS [Bottle] (PFIZER U.S.)
90 mg = $58.99
270 mg = $150.97 - Phenytek 200 MG CAPS [Bottle] (MYLAN)
30 mg = $42.89
90 mg = $92.36 - Phenytoin 125 MG/5ML SUSP [Bottle] (MORTON GROVE PHARMACEUTICALS)
237 5ml = $28.98
711 5ml = $80.96
Warning: This pricing information is subject to change at the sole discretion of DS Pharmacy. For the most current and up-to-date pricing information, please visit drugstore.com.
