PHENYTOIN tablet, chewable

Country: United States

Language: English

Source: NLM (National Library of Medicine)

Active ingredient:

PHENYTOIN (UNII: 6158TKW0C5) (PHENYTOIN - UNII:6158TKW0C5)

Available from:

American Health Packaging

INN (International Name):

PHENYTOIN

Composition:

PHENYTOIN 50 mg

Administration route:

ORAL

Prescription type:

PRESCRIPTION DRUG

Therapeutic indications:

Phenytoin chewable tablets are indicated for the treatment of generalized tonic-clonic (grand mal) and complex partial (psychomotor, temporal lobe) seizures and prevention and treatment of seizures occurring during or following neurosurgery. Phenytoin chewable tablets are contraindicated in patients with: - A history of hypersensitivity to phenytoin, its inactive ingredients, or other hydantoins [see Warnings and Precautions (5.5)] . Reactions have included angioedema. - A history of prior acute hepatotoxicity attributable to phenytoin [see Warnings and Precautions (5.8)] . - Coadministration with delavirdine because of the potential for loss of virologic response and possible resistance to delavirdine or to the class of non-nucleoside reverse transcriptase inhibitors. Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antiepileptic drugs (AEDs), such as phenytoin, during pregnancy. Physicians are advised to recommend that pregnant patients taking phenytoin enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll free number 1-888-233-2334, and must be done by patients themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/. Risk Summary In humans, prenatal exposure to phenytoin may increase the risks for congenital malformations and other adverse developmental outcomes. Prenatal phenytoin exposure is associated with an increased incidence of major malformations, including orofacial clefts and cardiac defects. In addition, the fetal hydantoin syndrome, a pattern of abnormalities including dysmorphic skull and facial features, nail and digit hypoplasia, growth abnormalities (including microcephaly), and cognitive deficits has been reported among children born to epileptic women who took phenytoin alone or in combination with other antiepileptic drugs during pregnancy [see Data] . There have been several reported cases of malignancies, including neuroblastoma, in children whose mothers received phenytoin during pregnancy. Administration of phenytoin to pregnant animals resulted in an increased incidence of fetal malformations and other manifestations of developmental toxicity (including embryofetal death, growth impairment, and behavioral abnormalities) in multiple species at clinically relevant doses [see Data] . In the U.S. general population, the estimated background risk of major birth defects and of miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown. Clinical Considerations Disease-associated maternal risk An increase in seizure frequency may occur during pregnancy because of altered phenytoin pharmacokinetics. Periodic measurement of serum phenytoin concentrations may be valuable in the management of pregnant women as a guide to appropriate adjustment of dosage [see Dosage and Administration (2.4, 2.8)] . However, postpartum restoration of the original dosage will probably be indicated [see Clinical Pharmacology (12.3)] . Fetal/Neonatal Adverse Reactions A potentially life-threatening bleeding disorder related to decreased levels of vitamin K-dependent clotting factors may occur in newborns exposed to phenytoin in utero . This drug-induced condition can be prevented with vitamin K administration to the mother before delivery and to the neonate after birth. Data Human Data Meta-analyses using data from published observational studies and registries have estimated an approximately 2.4-fold increased risk for any major malformation in children with prenatal phenytoin exposure compared to controls. An increased risk of heart defects, facial clefts, and digital hypoplasia has been reported. The fetal hydantoin syndrome is a pattern of congenital anomalies including craniofacial anomalies, nail and digital hypoplasia, prenatal-onset growth deficiency, and neurodevelopmental deficiencies. Animal Data Administration of phenytoin to pregnant rats, rabbits, and mice during organogenesis resulted in embryofetal death, fetal malformations, and decreased fetal growth. Malformations (including craniofacial, cardiovascular, neural, limb, and digit abnormalities) were observed in rats, rabbits, and mice at doses as low as 100 mg/kg, 75 mg/kg, and 12.5 mg/kg, respectively. Risk Summary Phenytoin is secreted in human milk. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for phenytoin and any potential adverse effects on the breastfed infant from phenytoin or from the underlying maternal condition. Initially, 5 mg/kg/day in two or three equally divided doses, with subsequent dosage individualized to a maximum of 300 mg daily. A recommended daily maintenance dosage is usually 4 mg/kg to 8 mg/kg. Children over 6 years and adolescents may require the minimum adult dosage (300 mg/day) [see Dosage and Administration (2.3)] . Phenytoin clearance tends to decrease with increasing age [see Clinical Pharmacology (12.3)] . Lower or less frequent dosing may be required [see Dosage and Administration (2.7)] . The liver is the chief site of biotransformation of phenytoin; patients with impaired liver function, elderly patients, or those who are gravely ill may show early signs of toxicity. Because the fraction of unbound phenytoin is increased in patients with renal or hepatic disease, or in those with hypoalbuminemia, the monitoring of phenytoin serum levels should be based on the unbound fraction in those patients. Patients who are intermediate or poor metabolizers of CYP2C9 substrates (e.g., *1/*3, *2/*2, *3/*3) may exhibit increased phenytoin serum concentrations compared to patients who are normal metabolizers (e.g., *1/*1). Thus, patients who are known to be intermediate or poor metabolizers may ultimately require lower doses of phenytoin to maintain similar steady-state concentrations compared to normal metabolizers. If early signs of dose-related central nervous system (CNS) toxicity develop, serum concentrations should be checked immediately [see Clinical Pharmacology (12.5)].

Product summary:

Phenytoin Chewable Tablets USP, 50 mg are yellow, uniform to slightly mottled, round normal convex tablets, scored and engraved with "T" above the score and "50" below the score on one side and plain on the other side. The tablets are banana flavored. They are supplied as follows: Unit dose packages of 30 (5 x 6) NDC 60687-156-25 Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Protect from moisture. FOR YOUR PROTECTION: Do not use if blister is torn or broken.

Authorization status:

Abbreviated New Drug Application

Patient Information leaflet

American Health Packaging
----------
Dispense with Medication Guide.
To order more Medication Guides call American Health Packaging at
1‐800‐707‐4621.
8415625/0323
MEDICATION GUIDE
Phenytoin (fen´ i toin) chewable tablets
What is the most important information I should know about phenytoin
chewable tablets?
1. Do not stop taking phenytoin chewable tablets without first talking
to your healthcare provider.
•
Stopping phenytoin chewable tablets suddenly can cause serious
problems.
•
Stopping a seizure medicine suddenly can cause you to have seizures
more often or seizures that
will not stop (status epilepticus).
2. Like other antiepileptic drugs, phenytoin chewable tablets may
cause suicidal thoughts or actions in a
very small number of people, about 1 in 500. Call a healthcare
provider right away if you have any of
these symptoms, especially if they are new, worse, or worry you:
•
Thoughts about suicide or dying
•
Attempts to commit suicide
•
New or worse depression
•
New or worse anxiety
•
Feeling agitated or restless
•
Panic attacks
•
Trouble sleeping (insomnia)
•
New or worse irritability
•
Acting aggressive, being angry, or violent
•
Acting on dangerous impulses
•
An extreme increase in activity and talking
(mania)
•
Other unusual changes in behavior or mood
Suicidal thoughts or actions can be caused by things other than
medicines. If you have suicidal thoughts
or actions, your healthcare provider may check for other causes.
How can I watch for early symptoms of suicidal thoughts and actions?
•
Pay attention to any changes, especially sudden changes, in mood,
behaviors, thoughts, or
feelings.
•
Keep all follow-up visits with your healthcare provider as scheduled.
Call your healthcare provider between visits as needed, especially if
you are worried about symptoms.
3. Phenytoin chewable tablets can cause a type of serious allergic
reaction that may affect different parts
of the body such as your liver, kidneys, blood, heart, skin or other
parts of your body. These can be ve

Summary of Product characteristics

PHENYTOIN- PHENYTOIN TABLET, CHEWABLE
AMERICAN HEALTH PACKAGING
----------
HIGHLIGHTS OF PRESCRIBING INFORMATION
THESE HIGHLIGHTS DO NOT INCLUDE ALL THE INFORMATION NEEDED TO USE
PHENYTOIN CHEWABLE
TABLETS SAFELY AND EFFECTIVELY. SEE FULL PRESCRIBING INFORMATION FOR
PHENYTOIN CHEWABLE
TABLETS.
PHENYTOIN CHEWABLE TABLETS, FOR ORAL USE
INITIAL U.S. APPROVAL: 1953
INDICATIONS AND USAGE
Phenytoin chewable tablets are indicated for the treatment of
generalized tonic-clonic (grand mal) and
complex partial (psychomotor, temporal lobe) seizures and prevention
and treatment of seizures
occurring during or following neurosurgery. ( 1)
DOSAGE AND ADMINISTRATION
NOT FOR ONCE-A-DAY DOSING ( 2.1)
Adult starting dose in patients who have received no previous
treatment is two phenytoin chewable
tablets three times a day, with dose adjustments as necessary. For
most adults, the satisfactory
maintenance dose will be six to eight phenytoin chewable tablets
daily; an increase to twelve phenytoin
chewable tablets daily may be made, if necessary. ( 2.2)
Pediatric starting dose is 5 mg/kg/day in two to three equally divided
doses, with dosage adjustments
as necessary, up to a maximum of 300 mg daily. Maintenance dosage is 4
mg/kg/day to 8 mg/kg/day. (
2.3)
Serum blood level determinations may be necessary for optimal dosage
adjustments—the clinically
effective serum total concentration is 10 mcg/mL to 20 mcg/mL (unbound
phenytoin concentration is 1
mcg/mL to 2 mcg/mL). ( 2.4)
DOSAGE FORMS AND STRENGTHS
Phenytoin chewable tablets are available as 50 mg scored chewable
tablets. ( 3)
CONTRAINDICATIONS
Hypersensitivity to phenytoin, its ingredients, or other hydantoins (
4, 5.5)
A history of prior acute hepatotoxicity attributable to phenytoin ( 4,
5.8)
Coadministration with delavirdine ( 4)
WARNINGS AND PRECAUTIONS
_Withdrawal Precipitated Seizure: _May precipitate status epilepticus.
Dose reductions or discontinuation
should be done gradually. ( 5.1)
_Suicidal Behavior and Ideation: _Monitor patients for the emergence
or worsening of d