FENITOIN (Phenytoin)

     Chemical name: 5,5-Difenil-2, 4-imidazolidindion (in the form of sodium salt)

     Description: The white crystalline powder. Almost nerastvorim in water, soluble in 1% caustic alkali solution.

     Pharmacology: Farmakologicheskoe action-protivoepilepticheskoe, protivosudorozhnoe, antiaritmicheskoe, miorelaksiruyuschee.

Has protivosudorozhnoy activity (without express sedative and hypnotic effect), reflected in the generalized and partial seizures. In high doses violates coordinated movements. Provides activator effect on the central (shorter period of immobilization is testing "despair" and reduces Ptosis due rezerpinom) antiaritmicheskoe at heart (reducing the maximum speed depolarization, increases the threshold for excitability slows conductivity on beam and fiber Purkine Gisa). Suppresses vestibular despite decreases of some forms of the syndrome Menera. Affects active and passive transport of sodium and calcium ions across cell membranes and subkletochnye nerve cells. Significantly reduces the level of sodium in the neuron, because it reduces their income, blocking the Na +-K +-ATFazu brain and facilitate the active transport of cells. Changes in calcium fosfolipidnoe interaction cell membranes and reduces the active transport of potassium and calcium inhibits release neyromediatornyh amino acids (glutamate, aspartata) of the nerve end, than to protivosudorozhny effect. It has the ability to inhibit glutamatnye receptors. Protivoaritmicheskaya activity realized through lower central adrenergic effects on the heart, stabilize membranes in kardiomiotsitov uvelicheniie their permeability to potassium ions.

When admission into easily absorbed. The speed of absorption varies among different patients, it is time to Cmax variabelno - 3-15 h. Linked to 70-90% of the plasma proteins (with kidney failure-43%). Free passes gistagematicheskie barriers and quickly spread to organs and tissues (including the brain). Less than 5% is allocated to the urine unchanged to, the rest of liver enzymes transformed to inactive metabolites, mainly glyukuronidov (ekskretiruyutsya kidneys) and paraoksifenilnyh derivatives; The last part is made with bile. T1 / 2 in the plasma with / in the introduction, 9-14 h after oral admission, 22-28 h. Children (especially during growth) are encouraged to nominate phenytoin in combination with vitamins D and K, as possible development osteopaty like rickets, gipokaltsiemii violations collapse blood. With little additional effect should apply Phenobarbital or other protivoepileptichesky product. Used in addition, in cases of resistance karbamazepinu to treat neuralgia troynichnogo nerve. Fixes (50-90%) and supraventrikulyarnye zheludochkovye arrhythmia caused by overdoses of cardiac glycosides, but ineffectual when supraventrikulyarnyh arrhythmia etc. dysfunction. A clear effect of violations of rhythm during anaesthesia, cardiac catheterization, after operations on the heart, ie when broken central feature structures governing the sympathetic nervous system activity.

     Application: Epilepsy (spasmodic large seizures), and prevention of post postneyrohirurgicheskoy epilepsy, zheludochkovye arrhythmia, including intoxication with cardiac glycosides, some forms of the syndrome Menera, troynichnogo nerve neuralgia.

     Contraindications: Hypersensitivity, as a violation of the liver and kidney, cardiac failure, cachexy, Porphyria.

     Restrictions to apply: During pregnancy appointed only on the testimony of life.

     Adverse actions: Vertigo, agitation, tremor, ataxia, eye, fever, nausea, vomiting, changes in connective tissue (ogrubenie features of a person kontraktury Dyupyuitrena), allergic skin reaction (rash, itching); With long-term use (especially for children) - dispersion , malignant gums, Osteopathy, gipokaltsiemiya, megaloblastnaya anaemia, less-limfoadenopatiya, girsutizm.

     Networking: Uskoryayut biotransformation Phenobarbital and Carbamazepine, slow (may increase side effects), isoniazid and its derivatives, levomitsetin, kumariny, Aspirin acid teturam.

     Overdose: When concentrations in the blood of children for more than 20 mg / L may develop acute intoxication - eye, ataxia, a violation psyche, pain in the joints; In more severe cases, aetiology, flickering ventricular, trepetanie predserdy, asistoliya and coma. Treatment of symptomatic (no specific antidote).

     Dosing and Administration: inside, during or after the meal (to avoid gastric mucosa irritation). Adults on 1/2-1 table. 2-3 times a day if necessary to increase the daily dose of 3-4 tablets. the maximum daily dose of 8 tablets. Children under 5 years and 1 / 4 tablets. 2 times a day, for 5-8 years - 1 / 4 tablets. 3-4 times a day over eight years on 1/2-1 table. two times a day.

     Precautions: A careful selection of doses (epilepsy with a concentration in the blood at the 7-10 day care), because elimination-saturable process and increasing doses may be accompanied by a disproportionate increase in the plasma. When expressed adverse events should reduce the dose or stop the drug.

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