Previous studies of phenytoin neuropathy in selected groups of chronic epileptic patients on polytherapy have indicated a widely varying incidence of clinical or electrophysiological abnormalities. In 51 previously untreated epileptic patients followed prospectively on phenytoin or carbamazepine monotherapy, assisted by blood level monitoring, for 1-5 years we found no clinical evidence of neur...

We have investigated the effects of phenytoin on the electrical and mechanical activity of isolated calf and dog cardiac Purkinje fibers. Phenytoin (5-100 microM) lowers and shortens the plateau phase of the Purkinje fiber action potential and reduces twitch tension. We studied the ionic basis of these effects by combining a conventional two-microelectrode voltage clamp procedure with pharmacol...

The relative binding of acetaminophen, lidocaine, phenobarbital, phenytoin, quinidine, and theophylline to human tissues in vitro was studied using equilibrium dialysis. Pooled human serum plus homogenates of brain, heart, liver, and placenta were incubated at 4 degrees C with each drug at concentrations of 5 and 10 mmol/L. The percent binding of each drug to each tissue was calculated. Binding...

P-glycoprotein (P-gp), an ATP-dependant efflux pump transports a wide range of substrates across cellular membranes. Earlier studies have identified drug efflux due to the over-expression of P-gp as one of the causes for the resistance of phenytoin, an anti-epileptic drug (AED). While no clear evidence exists on the specific characteristics of phenytoin association with the human P-gp, this stu...

Cross reactivity between phenytoin, carbamazepine, and oxcarbazepine is reported. An 8 year old boy with partial seizures developed maculopapular rashes with itching on day 15 of carbamazepine therapy. After stopping carbamazepine, phenytoin 100 mg daily was prescribed two days later. On the 12th day of phenytoin therapy he developed cervical and axillary lymphadenopathy with fever. Lymph nodes...

The study determined the population estimates for Km and Vmax of phenytoin in Thai patients. The serum phenytoin concentrations collected prospectively from outpatients who received phenytoin were analyzed to estimate population pharmacokinetic parameters. There were 197 steady-state concentrations and associated dosage rates (mg/day) from 167 outpatients. The data were analyzed using NONMEM, a...

Fifty-four per cent of 41 chronically institutionalized adult patients with epilepsy had ataxia of gait (wide mean stride width). None of the following correlated with stride width: serum phenytoin, previous phenytoin toxicity, seizure frequency, or status epilepticus. Seventeen of the 41 patients had computed tomographic head scans. Patients with radiological evidence of cerebellar atrophy had...

Specific [3H]phenytoin binding in rat cortical membranes is associated with a micromolar affinity site through which diazepam can exert an enhancing effect. In contrast to diazepam, (+)bicuculline, isoguvacine and pentobarbital inhibited phenytoin binding, while GABA and (-)baclofen had no effect. Decreased phenytoin binding and a loss of the diazepam effect were observed in phospholipase A2-tr...

BACKGROUND Recurrent aphthous stomatitis (RAS) appears to be the most common type of oral ulcers. The lesion is usually self limited but its painful presentation results in some difficulties. Therefore, an efficient therapeutic strategy is required and currently existing therapies seem to be inadequate because of its unclear etiology. Here the therapeutic effect of triamcinolone acetonide ointm...

Clinical and electrical evidence of peripheral neuropathy may result from long term treatment with phenytoin or barbiturates, especially in combination, or after repeated exposure to toxic blood concentrations of either drug. Prolonged acute toxicity with phenytoin may rarely lead to permanent residual ataxia. Reversible dystonia may occasionally be precipitated by phenytoin or carbamazepine; a...