Common side effects include nausea, stomach pain, loss of appetite, poor coordination, Phenytoin was first made in 1908 by the German chemist Common side effects include nausea, stomach pain, loss of appetite, poor coordination, Phenytoin is known to be a causal factor in the development of Folate is present in food in a polyglutamate form, which is then converted into monoglutamates by There is no good evidence that phenytoin is a human Phenytoin therapy has been linked to the life-threatening skin reactions Phenytoin is primarily metabolized to its inactive form by the enzyme Phenytoin is also associated with induction of reversible Phenytoin may increase risk of suicidal thoughts or behavior. \\ Corrected\;phenytoin\;(equation\;2) = \frac{(Measured\;phenytoin)}{0.29 * Albumin + 0.1}
Loading doses (generally 10-20 mg/kg) Oral (PO) 1000 mg divided into three doses (400 mg initially, 300 mg 2 hours later, and 300 mg 2 hours later). 7 x wt (kg) Table 2 gives the approximate increase in concentration following doses of 250 to 750mg. $$
Initially by slow intravenous injection, or by intravenous infusion For Child 1 month–11 years Loading dose 20 mg/kg, then (by slow intravenous injection or by intravenous infusion) 2.5–5 mg/kg twice daily. Phenytoin sodium 'top-up' dose (mg) = (20 - measured concentration (mg/L)) x 0.7 x wt (kg) Table 2 gives the approximate increase in concentration following doses of 250–750mg. Because phenytoin has demonstrated some saturable and erratic oral absorption beyond 400 mg, the use of large oral loading doses is controversial.
For example, if the patient weighs 70kg and has a measured concentration of 5mg/L, a single dose … For phenytoin, a
PHENYTOIN (Dilantin) infusion. Phenytoin induces metabolizing enzymes in the liver. A small increase in dose may lead to a large increase in drug concentration as elimination becomes saturated. If phenytoin is already present but the patient is still not controlled, a 'top-up' loading dose may be useful. Top-Up Phenytoin = (20 –(measured concentration (mg/L)) x 0.7 x weight (kg) Sodium Dose Table 1 describes how much the serum concentration will increase with a 'top-up' loading dose. Osborn HH, et al. It hasa rapid onset of action and is highly protein bound. Phenytoin for neuroprotection in patients with acute optic neuritis: a randomised, placebo-controlled, phase 2 trial, The Lancet Neurology, Volume 15, Issue 3, March 2016, Pages 259–269 Using mgPE, no adjustment is needed when converting between phenytoin and fosphenytoin. It is used as an anticonvulsant in thetreatment of neonatal seizures unresponsive to Phenobarbitone. Conversion half-life to phenytoin ~15 minutes : SE: Hypotension, arrhythmias . Load: 20 mg/kg IV; … To avoid confusion, fosphenytoin doses are reported as "mgPE" (milligrams of phenytoin equivalents). Phenytoin typical doses are 3–5mg/kg/day. Two studies have examined the safety and efficacy of phenytoin oral loading doses. See phenytoin . New York, NY: Pfizer Inc.; 2013. The precise mechanism of anticonvulsantactivity has not been determined. Press 'Calculate' to view calculation results. Maintenance: See phenytoin • IV filter and NS flush following administration not required . Single-dose oral phenytoin loading. Because phenytoin has demonstrated some saturable and erratic oral absorption beyond 400 mg, the use of large oral loading doses is controversial. $$
Liver disease: Do not use oral loading dose. There is limited data regarding an adjustment factor for loading phenytoin in obese patients. IV loading does achieve quicker therapeutic level (3 hours), so there may still be a risk of seizure for a short time after oral loading.