Phenytoin sodium

Phenytoin. Phenytoin sodium is sodium diphenylhydantoin [630-93-3] which is stmcturally related to the barbiturates. It was originally introduced as an anticonvulsant (18) (see Hypnotics, sedatives, and anticonvulsants) and later found to have antiarrhythmic properties (19), although not approved by the PDA for any arrhythmic indications. Phenytoin is effective in the treatment of ventricular arrhythmias associated with acute MI and with digitalis toxicity (20). It is not very effective in treatment of supraventricular arrhythmias (20). 

Table 1 In Vitro Dissolution Characteristics of Two Commercial Phenytoin Sodium Capsule... 

Phenytoin decreases folic add absorption, but folic acid replacement enhances phenytoin clearance and can result in loss of efficacy. Phenytoin tablets and suspension contain phenytoin acid, while the capsules and parenteral solution are phenytoin sodium, which is 92% phenytoin. Clinicians should remember that there are two different strengths of phenytoin suspension and capsules. 

FIGURE 56-1. Algorithm for the management of generalized convulsive status epilepticus. (CBC, complete blood cell count EEG, electroencephalogram HR, heart rate PE, phenytoin sodium equivalents PR, per rectum RR, respiratory rate.)... 

The dose of fosphenytoin sodium is expressed as phenytoin sodium equivalents (PE). 

Likewise, the antoconvulsant phenytoin sodium and neomycin—an aminoglycoside antibiotic also decrease the cholesterol levels, and... 

Phenytoin sodium 0.4 g 1 -Naphthol benzein Each ml of 0.1 N HC104 e= 0.02743 g of C15H N2Na02... 

A pediatric patient was presented to the emergency room (ER) experiencing seizures for which 150-mg Cerebyx (fosphenytoin anticonvulsant) IV was ordered. The pharmacy technician took the call for Cerebyx and delivered three 10-mL vials of Cerebyx 50-mg PE (phenytoin sodium equivalents) per mL to the ER as a floor stock transaction. A nurse misread the 50-mg PE/mL on the 10-mL container label, making the assumption that the entire vial contained 50 mg PE. The contents of all three vials were prepared for administration. Instead of 150 mg PE, the patient was administered ten times the intended dose, or 1,500 mg PE. The patient later died. The ER staff only discovered the error after the patient s blood phenytoin levels were returned from the laboratory. 

FOSPHENYTOIN The dose, concentration in dosing solutions and infusion rate of IV fosphenytoin is expressed as phenytoin sodium equivalents (PE) to avoid the need to perform molecular weight-based adjustments when coverting between fosphenytoin and phenytoin sodium doses. Prescribe and dipense fosphenytoin in PEs. Fosphenytoin has important differences in administration from those for parenteral phenytoin sodium. 

PHENYTOIN AND PHENYTOIN SODIUM, OPAL Phenytoin sodium contains 92% phenytoin. Phenytoin and phenytoin sodium prompt are not for once/day dosing. Phenytoin sodium extended may be used for once/day dosing. 

Single daily dosage - In adults, if seizure control is established with divided doses of three 100 mg extended phenytoin sodium capsules daily, once/day dosage with 300 mg may be considered patient compliance is essential on a once/day regimen. Only extended phenytoin sodium capsules are recommended once/day. 

Incompatibilities Do not mix IV minocycline before or during administration with any solutions containing the following Adrenocorticotropic hormone (ACTH), aminophylline, amobarbital sodium, amphotericin B, bicarbonate infusion mixtures, calcium gluconate or chloride, carbenicillin, cephalothin sodium, cefazolin sodium, chloramphenicol succinate, colistin sulfate, heparin sodium, hydrocortisone sodium succinate, iodine sodium, methicillin sodium, novobiocin, penicillin, pentobarbital, phenytoin sodium, polymyxin, prochlorperazine, sodium ascorbate, sulfadiazine, sulfisoxazole, thiopental sodium, vitamin K (sodium bisulfate or sodium salt), whole blood. 

Admixture Incompatibilities Physical incompatibilities resulted when linezolid IV injection was combined with the following drugs during simulated Y-site administration amphotericin B, chlorpromazine hydrochloride, diazepam, pentamidine isothionate, erythromycin lactobionate, phenytoin sodium, and trimethoprim-sulfamethoxazole. Additionally, chemical incompatibility resulted when linezolid IV injection was combined with ceftriaxone sodium. 

Phenobarbitone, Phenytoin, sodium valproate Inoreased sedation, increased... 

Reduced ethinyl estradiol concentrations have been associated with concomitant use of substances that induce hepatic microsomal enzymes, such as rifampin, rifabutin, barbiturates, phenylbutazone, phenytoin sodium, griseofulvin, topiramate, some protease inhibitors, modafinil, and possibly St. John s wort ... 

Absorption of phenytoin is highly dependent on the formulation of the dosage form. Particle size and pharmaceutical additives affect both the rate and the extent of absorption. Absorption of phenytoin sodium from the gastrointestinal tract is nearly complete in most patients, although the time to peak may range from 3 to 12 hours. Absorption after intramuscular injection is unpredictable, and some drug precipitation in the muscle occurs this route of administration is not recommended for phenytoin. In contrast, fosphenytoin, a more soluble phosphate prodrug of phenytoin, is well absorbed after intramuscular administration. 

Phenytoin, Sodium Capsules (Prompt or Extended), Oral Suspension... 

Phenytoin sodium/ Dilantin/ Elkins-Sinn/ Anticonvulsant... 

Succinylcholine solutions contained 0.05% (w/v) methyl- -hydroxybenzoate as stabilizer. Phenytoin (sodium salt) and decanol were supplied by Sigma (St. Louis, MO) other materials were tricaprylylmethylammoniura chloride or Aliquat 336S (General Mills Chemicals, Inc., Kankakee, IL). Solutions of sodium phenytoin were prepared by serial dilution while keeping both pH and ionic strength at constant values, 10 and 0.1 mol/1, respectively. The selectivity coefficients were determined at pH 10.0 and 0.1 mol/1 ionic strength, both adjusted with borax-NaOH buffer solution of pH 10.0. 

The USP contains Phenytoin, Phenytoin Sodium and the following formulations ... 

Extended Phenytoin Sodium Capsules Prompt Phenytoin Sodium Capsules. 

USP reference standards for Phenytoin and Phenytoin Sodium are available. 

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