Фенитоин Constitutional formula

The description is actual on 19.08.2015

  • Latin name: Phenytoinum
  • ATH code: N03AB02, N03AB52
  • Chemical formula: C15H12N2O2
  • CAS code: 57-41-0

Chemical name


Chemical properties

Phenytoinum – the antiepileptic means derivative of hydantoin, on the chemical structure is close to barbituric acid. Substance is included into the list of the major lek. means of WHO, in the list of vital drugs.

Means was synthesized in 1908, and to 1937 found its anticonvulsant properties. Substance represents white crystal powder, almost not soluble in water. Connection can be dissolved in r-ah caustic alkalis (1%), its molecular weight = 252,3 grams on mol.

As a part of various drugs use mix of hydrosodium carbonate and diphenylhydantoin. Medicine is entered orally and parenterally.

Pharmacological action

Anticonvulsant, antiarrhytmic, antiepileptic, myorelaxation.

Pharmacodynamics and pharmacokinetics

Anticonvulsant activity of means is rather high and is not followed by drowsiness and block. Phenytoinum – the effective bioelectric stabilizer. In high dosages substance is capable to break coordination of movements. Means activates the central nervous system, makes antiarrhytmic impact on a cardiac muscle, raises an excitation threshold, reduces the speed of passing of impulses on Purkinye's fibers and a ventriculonector.

The mechanism of effect of substance is not up to the end studied, however it is possible to assume that its fundamental property is ability of medicine to stabilize neyronalny membranes of a body of nervous cells, synoptic bonds. Thus, it is possible to limit process of distribution of neyronalny excitement and convulsive activity. Substance influences fabrics back and a brain, autonomous a ganglion, the cardiac muscle, peripheral nerves which is carrying out system of heart, unstriated muscles of vessels and intestines. Phenytoinum reduces concentration of sodium in neurons, facilitates transport of ions of sodium from cells, reduces intracellular transport of calcium. Also means influences work of neuroglias, fibroblasts and endocrine cells. Ability of this connection to accelerate healing of wounds, to improve supply with oxygen of cells, bodies and fabrics in the conditions of a hypoxia and poisoning with toxins, to suppress activity of glutamate receptors is found.

In therapeutic doses drug calms and has moderately tonic effect, does not cause accustoming.

At oral administration active ingredient is easily acquired by an organism, however its pharmacokinetic parameters differ at various groups of patients. The maximum concentration in blood reaches within 3-15 hours (to 28 for tablets). The effect of reception of substance after reception of tablets is observed in 60 minutes, after intravenous administration – in several minutes. About 80% of substance take up with proteins of a blood plasma. At the persons suffering from diseases of kidneys, this indicator reaches 43%. Means quickly breaks a blood-brain barrier, is distributed practically on all to fabrics and bodies.

Less than 5% of connection are removed by means of kidneys, the rest is exposed to a metabolism in a liver (turns into inactive glucuronides and paraoksifenila which then are removed with bile).

The combined use of Phenytoinum with vitamin D and To, phenobarbital and other antiepileptic means is shown.

Indications to use

Medicine is appointed:

  • at epilepsy;
  • as a prophylactic after operations and injuries;
  • at supraventricular and ventricular arrhythmia, which the cardiac glycosides or antidepressants caused by overdose;
  • for treatment of a syndrome of Menyer;
  • at an epileptiform neuralgia, especially at resistance to carbamazepine;
  • to patients with the epileptic status with toniko-clonic attacks difficult partial attacks;
  • at disturbance of thought processes, behavioural frustration and frustration of mentality;
  • sick ulcer colitis or syndrome of the angry intestines, at inefficiency of other methods of treatment;
  • at squint and glaucoma;
  • to patients with disturbances of processes of regeneration (caries, burns, a scleroderma, ulcers);
  • at a garapata disease and a hypothalamic syndrome.


Medicine is contraindicated:

  • at a serious illness of kidneys or liver;
  • to patients with heart failure, AV blockade 2 or 3 degrees, bradycardia;
  • at a leukopenia or a cachexia;
  • to the feeding women;
  • to the persons possessing hypersensitivity to substance;
  • at a porphyria;
  • to pregnant women;
  • at Morganyi-Adams-Stokes's syndrome.

It is necessary to be careful to alcoholics, a sick diabetes mellitus, at a hyperthermia or a lupus erythematosus.

Side effects

At use of Phenytoinum:

  • at 2-4% of patients skin allergic reactions, korepodobny rash develop (to cancel medicine before elimination of symptoms of rash);
  • seldom there are heavy allergic reactions, an extensive enanthesis, fever, Stephens-Johnson's syndrome, hepatitis, an erythema, Quincke's diseases;
  • dozozavisimy disturbances from a nervous system, fibrillation can develop a century and lips, a nystagmus, an ataxy, concern, a tremor, dizziness, an acrimony, an insomniya, touch neuropathy (long reception of high doses);
  • there is a hyperplasia of gums, osteomalacy, a macrocytosis, is rare – megaplastic anemia, a pancytopenia, thrombocytopenia, hemolitic anemia, a hirsutism, a lymphadenopathy;
  • the hypertrichosis, hyperpegmentation, coarsening of features, polyarthritis, weight reduction can be observed.

At reception of the first dose can develop: nausea, dyspepsia, frustration from a gastrointestinal tract, gastritis, a gastralgia, increase of level of enzymes of a liver. Side effects such it is possible to warn if to take a pill during food.

Phenytoinum, application instruction (Way and dosage)

The dosage is selected individually, depending on an illness and age of the patient.

The drug Phenytoinum dose for treatment of not epileptic diseases is several times lower, than at treatment of epilepsy. A pill is taken during food.

The daily dosage for adults makes 1-3 tablets distributed on 2-3 receptions. If necessary it is possible to increase a daily dosage to 4 tablets.

The maximum daily dosage makes 8 tablets. For once the patient can take 3 pill.

Aged till 5 flyings appoint on quarters of a tablet, 2 times a day. Children are from 5 to 8 years old – on quarters, 3-4 times a day. To the children who reached 8-year age about 1-2 tablets, are recommended to take for 2 receptions.

Medicine is often combined with other drugs, antiepileptic means.

Duration of treatment is defined by the specialist.


Reception of high doses of means leads to development for a long time: nystagmus, ataxy, hyperkinesias, diplopia, touch neuropathy. Also can be shown: strengthening of attacks of epilepsy, lump, sopor, hyperglycemia.

Substance has no specific antidote. Treatment should be carried out according to the shown symptoms.


At a combination to theophylline there is a mutual easing of efficiency both lek. means.

Medicine exerts impact on efficiency of paracetamol.

Drug reduces plasma concentration of Nimodipin, Verapamil and Felodipin.

Acetazoleamide increases probability of development of rickets or osteomalacy.

Substance exerts impact on efficiency of glucocorticosteroids, antifungal means, digitoxin, furosemide, the oral combined contraceptives, rifampicin, clozapine, a dikumarol, doxycycline, ekstrogen, quinidine, vitamin D.

At a drug combination to the means oppressing work of TsNS, perhaps mutual strengthening of effects.

The combined drug intake with Flukonazol, Miconazolum, Amphotericinum In, Ketokonazoly, intrakonazoly, Hloramfenikoly, Diazepam, blockers of histamine H1 receptors, the Isoniazid, Omeprazol, estrogen, phenylbutazone, suktsinimida, sulfonamides, Trazodonum, Sulfinpyrazonum, a halothane, felbamaty, methylphenidate, Fluoxetine or salicylates leads to increase of its plasma concentration and increase of risk of development of side reactions.

The concomitant use of substance with derivatives of a fenotiazin, thioridazine, chloropromazinum, Phenobarbital, prochlorperazine, Klaritromitsin, antineoplastic means can lead to increase of concentration of Phenytoinum in blood.

The acyclovir and Sukralfat reduce efficiency and plasma concentration of means.

With extra care medicine is combined with valproic acid. Acid leads to reduction of efficiency and concentration in blood of active ingredient, especially in the first several weeks of carrying out therapy. Then plasma concentration of Phenytoinum is recovered to normal level. Also it is considered that valproic acid increases quantity of a secondary inactive, but gepatotoksichny metabolite.

The concomitant use of medicine with gabapentiny, desipramine, diltiazem, nifidepiny, Disulfiramum can lead to increase of toxicity of medicines and increase in plasma concentration of Phenytoinum.

Efficiency of drug decreases at its combined reception with carbamazepine, Reserpinum, vigabatriny, folic acid, sukralfaty a little.

At a combination of funds from 200 mg of a pyridoxine in days, its plasma concentration and efficiency decreases.

Nature of interaction of Phenytoinum with ritonaviry is not finalized, cases of increase of plasma concentration of antiepileptic means were registered.

Terms of sale

The recipe is necessary.

Storage conditions

Tablets store in the dry, dark place, at the room temperature.

Period of validity

5 years.

Special instructions

Patients with epilepsy cannot sharply stop taking medicine, it can lead to development of a withdrawal. At an urgent need of drug withdrawal (the allergy to drug, hypersensitivity reactions) is recommended to use other anticonvulsants.

Treatments by this means exerts impact on the level of bilirubin, cholesterol, an alkaline phosphatase, glucose, enzymes of a liver, calcium of blood serum and hormone of thyroxine.

If at the patient hypersensitivity reactions to hydantoic anticonvulsants were observed earlier, then development of similar reactions to this substance is possible.

Phenytoinum is actively metabolized in liver tissues therefore during treatment patients need to observe care with a liver failure.

During treatment it is recommended to eat and provide standard daily rate of production of vitamin D normally.

During passing of a course of treatment means cannot be steered the car and to carry out potentially dangerous types of activity.

To children

It is necessary to correct a daily dosage and the mode of dosing. Use of medicine at children during the periods of active growth can lead to disturbances in growth and development of connecting fabric.

Dipheninum, Dilantinum, Diphenylhydantoin.

About Phenytoinum

Responses of patients good. Medicine is well transferred, costs little, does not lose the anticonvulsant properties even at prolonged use. Many positive comments about this medicine were left by the patients accepting it as a part of complex treatment.

Phenytoinum price where to buy

It is possible to buy Phenytoinum which is a part of tablets Difenin for 30-50 rubles, 10 tablets on 100 mg.

Section: Active ingredients
PAY ATTENTION! Information on active ingredients on the website is help generalizing, collected from public sources and can form the basis for making decision on use of these substances it is not aware of treatment. Before substance Phenytoinum use surely consult with the attending physician.
Tablets Pantokaltsin
Valine formula
Potassium acetate formula
Doksilamina succinate