Phenytoin is a Medicine belongs to Antiepileptics group whose information about Brand can be referenced from   Book : Martindale    Page : 545   Edition : 38  

  ►   Brandname : Dilantin, Epicent, Phenytek, Epanutin, Phenhydan, Aleviatin
  ►  Strength : Chewable tablets with 50 mg.  Capsule with 100 mg.  Oral Suspension with 125 mg/5mL.  Injection with 50 mg/ml.  Extended- release capsule with 30 mg.  Extended- release capsule with 100 mg.  Slow release capsules with 200 mg.  Slow release capsules with 300 mg. 

Reference of this Medicine for its Strength can be taken from   Book : Basic & Clinical pharmacology    Page : 427   Edition : 12  
A Route of administration in pharmacology and toxicology is the path by which a drug, fluid, poison, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance is applied. Common examples include oral and intravenous administration.

  ►  Route of administration : IV, Oral
Reference :-   Book : Martindale    Page : 545   Edition : 37  

Dosing of Medicine differ in Adult & Pediatrics ↓

Adult Dose

S.No Ailment   Route   Dose Min   Dose Max   Unit   Dosage Form   Frequency   Additional Info
1 Epilepsy Oral For epilepsy the dose of phenytoin should be adjusted to the needs of the individual patient to achieve adequate control of seizures, preferably with monitoring of plasma concentrations; in many patients control requires total plasma-phenytoin concentrations of 10 to 20 micrograms/mL (40 to 80 micromoles/litre). A suggested initial oral dose of phenytoin or phenytoin sodium given as a single dose or in divided doses is 3 to 4 mg/kg daily or 150 to 300 mg daily progressively increased with care to 600 mg daily if necessary; the suggested minimum interval between increments has ranged from about 7 to 10 days. Particular care is needed at higher doses, where saturation of metabolism may mean that a small increment produces a large rise in plasma concentrations.
2 Tonic-clonic status epilepticus Injection Treatment usually begun with a benzodiazepine such as diazepam or lorazepam given intravenously or rectally, and followed by phenytoin sodium intravenously. A suggested dose of phenytoin sodium is 10 to 15 mg/kg given by slow intravenous injection or by intermittent infusion at a uniform rate of not more than 50 mg/minute.
3 Seizures associated with neurosurgery IM Injection For the prevention and treatment of seizures associated with neurosurgery in patients who have not previously taken phenytoin sodium, a suggested intramuscular dose is 100 to 200 mg given at 4- hourly intervals during surgery and continued postoperatively for 48 to 72 hours. Thereafter, the dose should be reduced to a maintenance dose of 300 mg daily and adjusted according to plasma-phenytoin concentrations.

Ref :-  Book : Martindale    Page : 538   Edition : 38  

Pediatric Dose

S.No Ailment   Age Min   Age Max   Weight ( Kg ) Route   Dose Min   Dose Max   Unit   Dosage Form   Frequency  Additional Info  
1 Epilepsy
2 Seizures associated with neurosurgery or trauma slow IV injection/infusion Injection

Ref :- Book : Martindale    Page : 539   Edition : 38  
Precaution :- If a Patient is using 'Phenytoin' drug in  MEGALOBLASTIC ANEMIAS  disease, then Please Do not use .

Precaution :- If a Patient is using 'Phenytoin' drug in  Juvenile Myoclonic Epilepsy  disease, then Please exacerbates myoclonus .

Precaution :- If a Patient is using 'Phenytoin' drug in  Epilapsy  disease, then Please Contraindication: Pregnancy .

Precaution :- If a Patient is using 'Phenytoin' drug in ACUTE VIRAL HEPATITIS disease, then Please should be avoided   if he ever suffered from Siezure disorders disease.
Precaution :- If a Patient is using 'Phenytoin' drug in Acute Hepatitis disease, then Please Can cause liver injury   if he ever suffered from Siezure disorders disease.
►  Side Effect : Ataxia, Nystagmus, Incoordination, Confusion, Gingival hyperplasia, Hirsutism, Facial coarsening, Serious adverse effects are, Agranulocytosis, leucopenia, Pancytopenia, Thrombocytopenia, Megaloblastic anaemia, Hepatitis, Stevens-Johnson syndrome, Toxic epidermal necrolysis
Ref :-   Book : Principle of Pharmacology (The Pathophysiologic Basis of Drug Therapy)    Page : 236   Edition : 3.   Martindale    Page : 236   Edition : 3.  

►  Drug Interaction : Drug interaction of Phenytoin is with Sex hormones, oral contraceptives, , , Anticoagulant , Corticosteroids,  Dopamine , Lidocaine , Quinidine
Ref :-   Book : Martindale    Page : 542   Edition : 38.   Martindale    Page : 542   Edition : 38.   Martindale    Page : 539.2   Edition : 37.  

  ►    Mechanism of Drug Drug Interaction :  There are complex interactions between antiepileptics, and toxicity may be enhanced without a corresponding increase in antiepileptic activity. Such interactions are very variable and unpredictable and plasma monitoring is often advisable with combination therapy. Since phenytoin is extensively bound to plasma proteins it can be displaced by drugs competing for protein- binding sites, thus liberating more free (pharmacologically active) phenytoin into the plasma. However, elevation of free phenytoin is reported to be of little clinical significance provided hepatic function is not impaired. A potentially more serious type of interaction may occur because phenytoin metabolism is saturable: toxic concentrations of phenytoin can develop in patients given drugs that inhibit phenytoin metabolism even to quite a minor degree. Phenytoin itself is also a potent enzyme inducer, and induces the metabolism of a number of drugs, including some antibacterials, anticoagulants, corticosteroids, quinidine, and sex hormones (notably, oral contraceptives). The hypotensive properties of dopamine and the cardiac depressant properties of drugs such as lidocaine may be dangerously enhanced by intravenous phenytoin.
Ref :-   Book : Martindale    Page : 542   Edition : 38.  

►  Contraindication : SA node block, Hydantoin hypersensitivity, Sinus bradycardia, Second or third degree AV block, Stokes-Adams syndrome
Ref :-   Book : Principle of Pharmacology (The Pathophysiologic Basis of Drug Therapy)    Page : 236   Edition : 3.  
  ►  Mechanism of Action :   It alters Na, K and Ca conductance, membrane potential and the concentration of amino acids and the Neurotransmitters NE, ACH and GABA.The major action of Phenytoin is to block sodium channels and inhibits the generation of rapidly repetitive action potentials
Ref :-   Book : Basic & Clinical pharmacology    Page : 407   Edition : 12.  

Pathway of DIETARY Product

​   ► Act.Comp / Nutrient / Food / Herb as follows :- Valerian with Another pathway.  

  ►  Pathway with its reference as follows :-
  • Valeremic acid have Anticonvulsant --- (Kokate, C. (2013). Pharmacognosy (4th ed.). Pune: Nirali Prakashan. )

  •   ►  URL --
  • .
  • +C.+K.+Kokate .
  • +A.P.+Purohit .
  • +S.B.+Gokhale .

  • DIETARY Substance Interactions

    ​   ► This Medicine interact with :- VITAMIN B12 with Decrease in Nutrient Level.   VITAMIN B6 with Decrease in Nutrient Level.  

      ►  Reference :-
  • Gaby, A. (2006). A–Z Guide to Drug-Herb-Vitamin Interactions. 2nd ed. New York: Three Rivers Press

  •   ►  URL --

    ContraIndication DIETARY Substance

    ​   ► This Medicine contraindicate with :- VITAMIN B6 with Interect with anticonvulsins.   FOLIC ACID with Interect with anticonvulsins.   FOLIC ACID with cause seisures in patient taking phenytoin ..  

      ►  Reference :-
  • Eldelberg, D. The New Age of nutritional and herbal remedies. New Zealand
  • Williamson, E. (2009). Stockley's Herbal Medicines Interaction .. London: Pharmacutical press.

  •   ►  URL --

    ►   Route of Elimination :   Renal
    Ref :-   Book : Martindale    Page : 545   Edition : 37.  

    ►    Plasma Half-life :   Min value :-   mean plasma half-life appears to be about 22 hours at steady state,    Max value :-   NA
    Ref :-   Book : Martindale    Page : 545   Edition : 38.  

    ►    Peak Plasma Concentration :   Min value :-   NA    Max value :-   NA