Status epilepticus phenytoin

Occasionally, status epilepticus (an emergency situation characterized by continual seizure activity with no interruptions) can occur. Diazepam (Valium) is most often the initial drug prescribed for this condition. However, because the effects of diazepam last less than 1 hour, a longer-lasting anticonvulsant, such as phenytoin or phenobarbital, also must be given to control the seizure activity. 

Misra UK, Kalita J, Patel R. Sodium valproate vs phenytoin in status epilepticus A pilot study. Neurology 2006 67 340-342. 

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 Working Group on Status Epilepticus recommends that phenobar-bital be given after a BZ plus phenytoin has failed. Most practitioners agree that phenobarbital is the long-acting anticonvulsant of choice in patients with hypersensitivity to the hydantoins or in those with cardiac conduction abnormalities. 

Diazepam (Valium, Diastat) [C-IVj [Anxiolytic, Skeletal Muscle Relaxant, Anticonvulsant, Sedative/Hypnotic/ Benzodiazepine] Uses Anxiety, EtOH withdrawal, muscle spasm, status epilepticus, panic disorders, amnesia, preprocedure sedation Action Benzodiazepine Dose Adults. Status epilepticus 5-10 mg IV/IM Anxiety 2-5 mg IM/IV Preprocedure 5-10 mg IV just prior to procedure Peds. Status epilepticus 0.5-2 mg IV/IM Sedation 0.2-0.5 mg/kg IV (onset w/in 5IV and 30 min IM duration about 1 h IV and IM) Caution [D, / -] Contra Coma, CNS depression, resp d es-sion, NAG, severe uncontrolled pain, PRG Disp Tabs 2, 5, 10 mg soln 1, 5 mg/mL inj 5 mg/mL rectal gel 2.5, 5, 10, 20 mg/mL SE Sedation, amnesia, bradycardia, i BP, rash, X resp rate Interactions T Effects W/ antihistamines, azole antifungals, BBs, CNS depressants, cimetidine, ciprofloxin, disulfiram, INH, OCP, omeprazole, phenytoin, valproic acid, verapamil, EtOH, kava kava, valman T effects OF digoxin, diuretics X effects w/ barbiturates, carbamazepine. 

Status epilepticus (Phenytoin) IV Loading dose 15-18 mg/kg. Maintenance dose 300 mg/day in 2-3 divided doses. 

One of the authors recently encountered a 21-year-old male presenting to the emergency room in status epilepticus (prolonged, uncontrolled seizures). This patient had a seven-year history of epilepsy, well controlled with the drug phenytoin at a dose of 300 mg/day. Indeed, he had not experienced a seizure in more than a year. In the emergency... 

Phenobarbital Enhances phasic GABAa receptor responses reduces excitatory synaptic responses Nearly complete absorption not significantly bound to plasma proteins peak concentrations in Vi to 4 h no active metabolites tjy2 varies from 75 to 125 h Generalized tonic-clonic seizures, partial seizures, myoclonic seizures, generalized seizures, neonatal seizures, status epilepticus Toxicity Sedation, cognitive issues, ataxia, hyperactivity Interactions Valproate, carbamazepine, felbamate, phenytoin, cyclosporine, felodipine, lamotrigine, nifedipine, nimodipine, steroids, theophylline, verapamil, others... 

The therapeutic plasma level of phenytoin for most patients is between 10 and 20 g/mL. A loading dose can be given either orally or intravenously the latter, using fosphenytoin, is the method of choice for convulsive status epilepticus (discussed later). When oral therapy is started, it is common... 

Therapeutic uses Phenytoin is highly effective for all partial seizures (simple and complex), for tonic-clonic seizures, and in the treatment of status epilepticus caused by recurrent tonic-clonic seizures (Figure 15.3). Phenytoin is not effective for absence seizures, which often may worsen if such a patient is treated with this drug. 

In a multicenter, randomized, double-blind comparison of diazepam (0.15 mg/kg followed by phenytoin 18 mg/kg), lorazepam (0.1 mg/kg), phenobarbital (15 mg/kg), and phenytoin (18 mg/kg) in 518 patients with generalized convulsive status epilepticus, lorazepam was more effective than phenytoin and at least as effective as phenobarbital or diazepam plus phenytoin (1). Drug-related adverse effects did not differ significantly among the treatments and included hypoventilation (up to 17%), hypotension (up to 59%), and cardiac rhythm disturbances (up to 9%). 

Antiepilepsy drugs continued medication is essential to avoid status epilepticus. Drugs must be given parenterally (e.g. phenytoin, sodium valproate) or by rectum (e.g. carbamazepine) until the patient can absorb enterally. 

Fosphenytoin, a prodrug of phenytoin, is soluble in water, easier and safer to administer its conver-tion in the blood to phenytoin is rapid and it may be used as an alternative to phenytoin for status epilepticus (Table 20.1). 

DeToledo JC, Ramsay RE. Fosphenytoin and phenytoin in patients with status epilepticus improved tolerability versus increased costs. Drug Saf 2000 22(6) 459-66. 

Seizures are present in 30% of patients with star fruit intoxication [17], and most patients have convulsive [6, 8,10,11,13,14,17,18,19] or non-convulsive [16] status epilepticus. The mortality rate of patients with seizures occurring after star fruit intoxication (severe intoxication) is significantly higher than of patients without seizures [13, 17]. Phenytoin, midazolam, diazepam and phenobarbital seem to have little or no effect on the control of persistent seizures provoked by star fruit toxicity. However, significant clinical improvement of seizure was demonstrated in one patient after the use of profofol [20]. 

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