A Comparison of Phenytoin-loading Techniques in the Emergency Department

Abstract

Objectives: To compare the effectivenesses of three phenytoin-loading techniques. Methods: Patients with subtherapeutic phenytoin concentrations who presented within 48 hours of a seizure were randomized to receive either 20 mg/ kg of oral phenytoin (PO), divided in maximum doses of 400 mg every two hours, 18 mg/kg of intravenous phenytoin (IVP) at an initial infusion rate of 50 mg/min, or 18 mg/kg (phenytoin equivalents) of intravenous fosphenytoin (IVF) at an initial infusion rate of 150 mg/min. Results: A total of 45 patients were enrolled: 16 in the PO group, 14 in the IVP group, and 15 in the IVF group. The times required to reach therapeutic drug concentrations were (mean 6 standard deviation [SD]) 5.62 6 0.28 hours, 0.24 6 0.3 hours, and 0.21 6 0.28 hours, respectively. A total of 17, 27, and 32 adverse drug events were observed in the PO, IVP, and IVF groups, respectively, with significantly fewer events in the PO group (p ¼ 0.02, p ¼ 0.01). No significant difference was found between the numbers of necessary adjustments to the infusions in the two IV groups. The average time to safe emergency department discharge was significantly shorter for the IV groups compared with the PO group (p\0.001). Conclusions: Oral loading has fewer adverse drug events than either IV loading method, but its use may be limited when therapeutic concentrations are required quickly. Although IVF loading is faster, from an adverse-drug event perspective, no advantage of IVF over IVP was apparent.

Predictors of outcome in children with status epilepticus during resuscitation in pediatric emergency department: A retrospective observational study

“…Data comparing intravenous phenytoin and fosphenytoin have shown that the latter also causes cardiotoxicity, suggesting that the solvent is not the culprit. [2223] A consensus guideline recommended that intravenous phenytoin should be avoided in patients with cardiovascular disease or when symptoms of debilitating illness, emaciation, hyponatremia, peripheral vascular disease, hemodynamic instability, or sepsis coexist. [24] The increased mortality due to prehospital phenytoin might have resulted from failure to recognize these complications in our cohort.…”

Efficacy of levetiracetam versus fosphenytoin for the recurrence of seizures after status epilepticus

“…Although FPHT exhibits a lower incidence of adverse reactions, it can still cause blood pressure reduction and arrhythmia, which is an issue. [5,6] …”

Contraindications to Phenytoin in Emergency Department Patients with Seizures

“…Patients with contraindications may be at risk for phenytoin toxicity after administration. This is compounded by the fact that adverse drug effects can be influenced by route of administration (13). Additionally, patients not currently taking any seizure medication may be prescribed phenytoin by an emergency physician for long-term seizure management.…”