7 DRUG INTERACTIONS. Fosphenytoin is extensively bound to human plasma proteins. Drugs highly bound to albumin could increase the unbound fraction of. Mylan manufactures FOSPHENYTOIN SODIUM Injection in strengths of mg PE in 2ml Vial mg PE in 10 ml Vial. Category: Human Prescription Drug. Fosphenytoin, the long-awaited phosphate ester pro-drug of phenytoin, was developed to overcome many of the .. Cerebyx package insert. Morris Plains, N.J.
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Fosphenytoin sodium injection is a prodrug intended for parenteral administration; its active metabolite is phenytoin. The amount and concentration of fosphenytoin is always expressed in terms of mg PE. One mL of Pro-Epanutin contains 75 mg of fosphenytoin sodium equivalent to 50 mg of phenytoin sodium see section 4.
Pro-Epanutin is a clear, colourless to pale yellow, sterile solution buffered with trometamol adjusted to pH 8. Throughout all Pro-Epanutin product labelling, the amount and concentration of fosphenytoin is always expressed in terms of phenytoin sodium equivalents PE to avoid the need to perform molecular weight-based adjustments when converting between fosphenytoin and phenytoin sodium doses. Pro-Epanutin should always be prescribed and dispensed in phenytoin sodium equivalent units PE.
Note, however, that fosphenytoin has important differences in administration from parenteral phenytoin sodium see section 4. The IM route should be considered for adult patients when there is not an urgent need to control seizures. If rapid phenytoin loading is a primary goal, IV administration of Pro-Epanutin is preferred because the time to achieve therapeutic plasma phenytoin concentrations following IV administration is faster as compared to IM administration.
Pro-Epanutin should not be administered by IM route in emergency situations such as status epilepticus. Pro-Epanutin is intended for short-term parenteral administration, and has not been evaluated for periods of more than 5 days. The concentration should range from 1.
The use of a device controlling the rate of infusion is recommended. Continuous monitoring of electrocardiogram, blood pressure and respiratory function for the duration of the infusion is essential. The patient should also be observed throughout the period where maximal plasma phenytoin concentrations occur.
This is approximately 30 minutes after the end of the Pro-Epanutin infusions. Please refer to Tables for examples of dosing, dilution, and infusion time calculations. For Dose reduction in the Elderly or patients with Renal or Hepatic impairment, please see guidance towards the end of this section.
Intramuscular IM administration of Pro-Epanutin is not recommended in the treatment of status epilepticus. In order to obtain rapid seizure control in patients with continuous seizure activity, IV diazepam or lorazepam should be administered prior to administration of Pro-Epanutin.
See Table 1 for infusion times. If administration of Pro-Epanutin does not terminate seizures, the use of alternative anticonvulsants should be considered. Appropriate dose, dosing volume, number of vials of Pro-Epanutin, volume of diluent, and minimum infusion time should always be calculated for the patient’s exact body weight when not included in the examples. After administration of a loading dose, maintenance doses should typically be started at the next identified dosing interval.
For example, if the intended dose frequency is every 12 hours then the first maintenance dose of Pro-Epanutin should be administered 12 hours after the loading dose.
Dilution Cerebyx ® -fosphenytoin – GlobalRPH
Maintenance doses should be adjusted according to patient response and trough plasma phenytoin concentrations see Therapeutic Drug Monitoring. See Table 2 for infusion times. Table 2 displays dosing information for status epilepticus maintenance dose in adults. See Table 3 for infusion times. Table 3 displays dosing information for seizure treatment or prophylaxis loading dose in adults.
See Table 4 for infusion times. Table 4 displays dosing information for seizure treatment or prophylaxis maintenance dose in adults. Temporary substitution of oral phenytoin sodium therapy with Pro-Epanutin.
The same total daily phenytoin sodium equivalents PE dose and dosing frequency as for oral phenytoin sodium therapy should be used and can be administered by IV infusion or packqge IM injection. Doses should be adjusted according to patient response and trough plasma phenytoin concentrations see Therapeutic Drug Monitoring.
See Table 5 for infusion times. Table 5 displays dosing information for the temporary substitution of oral phenytoin sodium in adults. The doses of Pro-Epanutin for children have been predicted from the known pharmacokinetics dosphenytoin Pro-Epanutin in adults and children aged 5 to 10 years and of parenteral phenytoin in adults and children.
For Dose reduction in patients with Fosphfnytoin or Hepatic impairment, please see guidance towards the end of this section. In order to obtain rapid seizure control in patients with continuous seizure activity IV diazepam or lorazepam should be administered prior to administration of Pro-Epanutin. See Table 6 for infusion times.
See Table 7 for infusion times. Table 7 displays dosing information for status epilepticus maintenance dose in children.
See Table 8 for infusion times. Table 8 displays dosing information for seizure treatment or prophylaxis loading dose in children. See Table 9 for infusion times. Table 9 displays dosing information for seizure treatment or prophylaxis maintenance dose in children. The same total daily phenytoin sodium equivalents PE dose and dosing frequency as for oral phenytoin sodium therapy should be administered by IV infusion.
See Table 10 for infusion times. Table 10 displays dosing information for the temporary substitution of oral phenytoin sodium in children. Phenytoin metabolism is slightly decreased in elderly patients.
Packzge rate of conversion of IV Pro-Epanutin to phenytoin may be increased in these patients. While the clearance rate of total phenytoin is not affected, the plasma unbound phenytoin concentrations may be fosphdnytoin. Unbound concentration of phenytoin may be elevated in patients with hyperbilirubinaemia see section 4. It pcakage therefore more appropriate to measure plasma unbound phenytoin concentrations rather than plasma total phenytoin fophenytoin in these patients see section 5.
Prior to complete conversion, immunoanalytical techniques may significantly overestimate plasma phenytoin concentrations due to cross-reactivity with fosphenytoin.
Chromatographic assay methods e. HPLC accurately quantitate phenytoin concentrations in biological fluids in the presence of fosphenytoin. It is advised that blood samples to assess phenytoin concentration should not be obtained for at least 2 hours after IV Pro-Epanutin infusion or 4 hours after IM Pro-Epanutin injection.
Plasma phenytoin concentrations sustained above the optimal range may produce signs of acute toxicity see section 4. For this reason, plasma phenytoin concentrations may increase when IM or IV Pro-Epanutin is substituted for oral phenytoin sodium therapy. Fospyenytoin, it is not necessary to adjust the initial doses when substituting oral phenytoin with Pro-Epanutin or vice versa. Hypersensitivity to fosphenytoin sodium phenytoin or other hydantoins, or to any of the excipients listed in section 6.
Parenteral phenytoin affects ventricular automaticity. Pro-Epanutin is therefore, contra-indicated in patients with sinus bradycardia, sino-atrial block, second and third degree A-V block and Adams-Stokes syndrome. Coadministration of Pro-Epanutin is contra-indicated with delavirdine due to the potential for loss of virologic response and possible resistance to delavirdine fosphenytooin to the class of non-nucleoside reverse transcriptase inhibitors see section 4.
Pro-Epanutin is a prodrug intended for parenteral administration; its active metabolite is phenytoin.
Note that Pro-Epanutin has important differences in administration insrrt parenteral phenytoin sodium. Dosing errors associated with Pro-Epanutin have resulted in patients receiving the wrong dose of Pro-Epanutin.
In some cases, overdoses were associated with fatal outcomes, including in children under 5 years of age. To help minimize confusion, the prescribed dosphenytoin of Pro-Epanutin should always be expressed in milligrams of phenytoin equivalents mg PE see section 4. Care should be taken to ensure the appropriate volume of Pro-Epanutin is withdrawn from the vial packagge preparing the drug for administration.
Attention to these details may prevent some Pro-Epanutin medication errors from occurring. Cardiac resuscitative equipment should be available. Pro-Epanutin should be used with caution in patients with hypotension and severe ppackage insufficiency.
Severe cardiovascular reactions including atrial and ventricular conduction depression, ventricular fibrillation, asystole and fatalities pafkage been reported following phenytoin and fosphenytoin administration. A reduction in the rate of administration or discontinuation of dosing may be necessary see section 4. Severe cardiac complications have been reported in elderly, children especially infantsor gravely ill patients following administration of fosphenytoin.
Cardiac adverse events have also been reported in adults and children without underlying cardiac disease or comorbidities and at recommended doses and infusion rates.
Therefore, careful cardiac including respiratory monitoring is needed when administering IV loading doses of inseert. Patients with an acute cerebrovascular event may be at increased risk of hypotension and require particularly close monitoring. Phenytoin is not effective in absence seizures. If tonic-clonic seizures are present simultaneously with absence seizures, combined drug therapy is recommended.
Abrupt withdrawal of antiepileptic drugs may increase seizure frequency and may lead to status epilepticus. Suicidal ideation and behaviour have been reported in patients treated with anti-epileptic agents in several indications. A meta-analysis of randomised, placebo controlled trials of anti-epileptic drugs has also shown fosohenytoin small increased risk of suicidal ideation and behaviour. The mechanism of this risk is not known and the available data do not exclude fosphhenytoin possibility of an increased risk for fosphenytoin.
Therefore patients should be monitored for signs of suicidal ideation and behaviours and appropriate treatment should be considered. Patients and caregivers of patients should be advised to seek medical advice should signs of suicidal ideation or behaviour emerge. This may or may not be associated with extravasation. Packgae syndrome may not develop for several days after injection.
Although resolution of symptoms may occur without treatment, skin necrosis and limb ischemia have occurred that required surgical interventions and, in rare cases, amputation. Some of these events have been fatal or life threatening. Initial symptoms may resemble an acute viral infection.
Other common manifestations include arthralgias, jaundice, hepatomegaly, leukocytosis, and eosinophilia. The interval between first drug exposure and symptoms is usually weeks of treatment but has also been reported in individuals receiving anticonvulsants for 3 or more months.
If such signs and symptoms occur, the patient should be evaluated immediately. Fosphenytoin should be discontinued if an alternative etiology for the signs and symptoms cannot be established.
The syndrome is more severe in previously sensitized individuals.