Dilantin - Phenytoin

Anticonvulsdnts. An early observation that BN patients may have abnormal electroencephalogram (EEG) resnlts led to specnlation that binge eating may represent an atypical behavioral presentation of seiznre activity. Thus, the first controlled medication study for the treatment of BN evaluated the use of the antiseizure medication phenytoin (Dilantin). Phenytoin was not found to be significantly superior to placebo, and the earlier reports of EEG abnormalities were not confirmed. The results of a subsequent trial of carbamazepine (Tegretol), an anticonvulsant that has been reported to be effective in the treatment of bipolar disorder, were also disappointing. As a result, anticonvulsants are not routinely used in the treatment of BN. 

There are many drugs that increase the rate of the liver s metabolism. More commonly used medications that fall into this category include rifampin, which is used to treat tuberculosis, and dilantin, phenytoin, and carbamazepine, which are medications commonly used to treat seizures and epilepsy. Chronic alcohol abuse also speeds up the metabolism of the liver. Since all of these substances cause the liver to break down methadone faster then it normally would, one way to correct the problem would be to increase the dose of methadone or break down the dose into several smaller doses given throughout the day. This should only be done on a physician s advice. 

A small fraction of epileptics treated with anticonvulsants dilantin, phenytoin, diphenylhydantoin) develop folate deficiency. Epilepsy is not a rare disease. Hence, there is an awareness of the possibility of the occurrence of megaloblastic anemia in epileptics treated with the aforementioned anticonvulsant. Supplementing epileptics with folate can alleviate the deficiency however, the supplements may also result in an increase in Ihe seizure rate. Thus, physicians must be prepared to halt folate supplementation of epileptics beuig treated for anemia. 

Dilantin Phenytoin sod. Parke Davis Propylene glycol 40% Ethanol 10% IM, IV... 

Prescribing Information for Dilantin (Phenytoin Sodium Injection, U.S.P.), Warner-Lambert, 1994. 

Phenytoin (Dilantin) Phenytoin stabilizes neuronal membranes which reduces sodium and potassium currents during an action potential. Suppresses repetitive firing of neurons. Used in all types of epilepsy except absence seizures. Therapeutic serum concentrations are 10-20 pg/ml. Toxicity includes nystagmus, ataxia, other CNS disturbances, bone marrow suppression, gingival hyperplasia, hepatotoxicity, Gl disturbances. Intravenous administration may cause CNS depression, severe hypotension, arrhythmias and hyperkinesis. Metab 90% protein bound, meti)olized in liver. 

Dilantin Phenytoin Antiepileptic 31 % lower total phenytoin levels for generic Rosenbaum etal. (1994)... 

Ganapathi R, Hercbeigs Grabowski D, Ford J. Selective enhancement of vincristine cytotoxicity in multidrug-resistant tumor cells by dilantin (phenytoin). Cancer Res (1993) 53, 3262-5. Correction, ibid 6079. 

Causes of hypocalcemia include hypoparathyroidism, hypomagnesemia, alcoholism, hyperphosphatemia, blood product infusion (due to chelation by the citrate buffers), chronic renal failure, vitamin D deficiency, acute pancreatitis, alkalosis, and hypoalbuminemia. Medications that cause hypocalcemia include phosphate replacement products, loop diuretics, phenytoin (Dilantin, available as generic), pheno-barbital (available as generic), corticosteroids, aminoglycoside antibiotics, and acetazolamide (available as generic).34,39,42... 

Johnston, M.C., Sulik, K.K. and Dudley, K.H. (1979). Genetic and metabolic studies of the differential sensitivity of A/J and C57BL/6J mice to phenytoin ( Dilantin )-induced cleft lip. Teratology 19 33 A. 

Phenytoin is used primarily in the treatment of major epileptic attacks. Difhydan, alepsin, dilantin, and solantin are the primary synonyms for phenytoin. 

Phenytoin has the same main effects on the heart as lidocaine. Its use is essentially limited, and it is primarily used only as an oral replacement of lidocaine for paroxysmal tachycardia that is caused particularly by intoxication of digitahs drugs. Synonyms of this drug are dilantin and diphenylan. 

Phenobarbital Phenytoin (Dilantin) Tiagabine (Gabitril) Topiramate (Topamax) Valproic Acid (Depakene, Depakote) Zonisamide (Zonegran)... 

Phenytoin (Dilantin) [Anticenvulsant/Hydantoin] Uses Sz disorders Action X Sz spread in the motor cortex Dose Load Adults Peds. 15-20 mg/kg IV, 25 mg/min max or PO in 400-mg doses at 4-h intervals Maint Adults. Initial, 200 mg PO or IV bid or 300 mg hs then follow levels Peds. 4-7 mg/kg/24h PO or IV -s- daily-bid avoid PO susp (erratic absorption) Caution [D, +] Contra Heart block, sinus bradycardia Disp Caps, susp, inj SE Nystag-mus/ataxia early signs of tox gum hyperplasia w/ long-term use. IV BP, bradycardia, arrhythmias, phlebitis peripheral neuropathy, rash, blood dyscrasias, Stevens-Johnson synd Notes Levels Trough Just before next dose Therapeutic Peak 10-20 mcg/mL Toxic >20 mcg/mL phenytoin albumin bound, levels = bound free phenytoin w/ i albumin azotemia, low levels may be therapeutic (nl free levels) Interactions T Effects W/ amiodarone, allopurinol, chloramphenicol, disulfiram, INH, omeprazole, sulfonamides, quinolones, trimethoprim t... 

Phenytoin (Dilantin) was originally introduced for the control of convulsive disorders (see Chapter 32) but has now also been shown to be effective in the treatment of cardiac arrhythmias. Phenytoin appears to be particularly effective in treating ventricular arrhythmias in children. 

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