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Depacon (Valproate Sodium) - Indications and Dosage

 
 



INDICATIONS AND USAGE

DEPACON is indicated as an intravenous alternative in patients for whom oral administration of valproate products is temporarily not feasible in the following conditions:

DEPACON is indicated as monotherapy and adjunctive therapy in the treatment of patients with complex partial seizures that occur either in isolation or in association with other types of seizures. DEPACON is also indicated for use as sole and adjunctive therapy in the treatment of patients with simple and complex absence seizures, and adjunctively in patients with multiple seizure types that include absence seizures.

Simple absence is defined as very brief clouding of the sensorium or loss of consciousness accompanied by certain generalized epileptic discharges without other detectable clinical signs. Complex absence is the term used when other signs are also present.

SEE WARNINGS FOR STATEMENT REGARDING FATAL HEPATIC DYSFUNCTION.

DOSAGE AND ADMINISTRATION

DEPACON IS FOR INTRAVENOUS USE ONLY.

Use of DEPACON for periods of more than 14 days has not been studied. Patients should be switched to oral valproate products as soon as it is clinically feasible.

DEPACON should be administered as a 60 minute infusion (but not more than 20 mg/min) with the same frequency as the oral products, although plasma concentration monitoring and dosage adjustments may be necessary.

In one clinical safety study, approximately 90 patients with epilepsy and with no measurable plasma levels of valproate were given single infusions of DEPACON (up to 15 mg/kg and mean dose of 1184 mg) over 5-10 minutes (1.5-3.0 mg/kg/min). Patients generally tolerated the more rapid infusions well (see ADVERSE REACTIONS). This study was not designed to assess the effectiveness of these regimens. For pharmacokinetics with rapid infusions, see CLINICAL PHARMACOLOGY, Pharmacokinetics - Bioavailability.

Initial Exposure to Valproate

The following dosage recommendations were obtained from studies utilizing oral divalproex sodium products.

Complex Partial Seizures

For adults and children 10 years of age or older.

Monotherapy (Initial Therapy)

DEPACON has not been systematically studied as initial therapy. Patients should initiate therapy at 10 to 15 mg/kg/day. The dosage should be increased by 5 to 10 mg/kg/week to achieve optimal clinical response. Ordinarily, optimal clinical response is achieved at daily doses below 60 mg/kg/day. If satisfactory clinical response has not been achieved, plasma levels should be measured to determine whether or not they are in the usually accepted therapeutic range (50 to 100 µg/mL). No recommendation regarding the safety of valproate for use at doses above 60 mg/kg/day can be made.

The probability of thrombocytopenia increases significantly at total trough valproate plasma concentrations above 110 µg/mL in females and 135 µg/mL in males. The benefit of improved seizure control with higher doses should be weighed against the possibility of a greater incidence of adverse reactions.

Conversion to Monotherapy

Patients should initiate therapy at 10 to 15 mg/kg/day. The dosage should be increased by 5 to 10 mg/kg/week to achieve optimal clinical response. Ordinarily, optimal clinical response is achieved at daily doses below 60 mg/kg/day. If satisfactory clinical response has not been achieved, plasma levels should be measured to determine whether or not they are in the usually accepted therapeutic range (50-100 µg/mL). No recommendation regarding the safety of valproate for use at doses above 60 mg/kg/day can be made. Concomitant antiepilepsy drug (AED) dosage can ordinarily be reduced by approximately 25% every 2 weeks. This reduction may be started at initiation of DEPACON therapy, or delayed by 1 to 2 weeks if there is a concern that seizures are likely to occur with a reduction. The speed and duration of withdrawal of the concomitant AED can be highly variable, and patients should be monitored closely during this period for increased seizure frequency.

Adjunctive Therapy

DEPACON may be added to the patient's regimen at a dosage of 10 to 15 mg/kg/day. The dosage may be increased by 5 to 10 mg/kg/week to achieve optimal clinical response. Ordinarily, optimal clinical response is achieved at daily doses below 60 mg/kg/day. If satisfactory clinical response has not been achieved, plasma levels should be measured to determine whether or not they are in the usually accepted therapeutic range (50 to 100 µg/mL). No recommendation regarding the safety of valproate for use at doses above 60 mg/kg/day can be made. If the total daily dose exceeds 250 mg, it should be given in divided doses.

In a study of adjunctive therapy for complex partial seizures in which patients were receiving either carbamazepine or phenytoin in addition to DEPAKOTE (divalproex sodium), no adjustment of carbamazepine or phenytoin dosage was needed (see  CLINICAL STUDIES). However, since valproate may interact with these or other concurrently administered AEDs as well as other drugs (see Drug Interactions), periodic plasma concentration determinations of concomitant AEDs are recommended during the early course of therapy (see PRECAUTIONS - Drug Interactions).

Simple and Complex Absence Seizures

The recommended initial dose is 15 mg/kg/day, increasing at one week intervals by 5 to 10 mg/kg/day until seizures are controlled or side effects preclude further increases. The maximum recommended dosage is 60 mg/kg/day. If the total daily dose exceeds 250 mg, it should be given in divided doses.

A good correlation has not been established between daily dose, serum concentrations, and therapeutic effect. However, therapeutic valproate serum concentrations for most patients with absence seizures is considered to range from 50 to 100 µg/mL. Some patients may be controlled with lower or higher serum concentrations (see  CLINICAL PHARMACOLOGY).

As the DEPACON dosage is titrated upward, blood concentrations of phenobarbital and/or phenytoin may be affected (see PRECAUTIONS).

Antiepilepsy drugs should not be abruptly discontinued in patients in whom the drug is administered to prevent major seizures because of the strong possibility of precipitating status epilepticus with attendant hypoxia and threat to life.

Replacement Therapy

When switching from oral valproate products, the total daily dose of DEPACON should be equivalent to the total daily dose of the oral valproate product (see  CLINICAL PHARMACOLOGY), and should be administered as a 60 minute infusion (but not more than 20 mg/min) with the same frequency as the oral products, although plasma concentration monitoring and dosage adjustments may be necessary. Patients receiving doses near the maximum recommended daily dose of 60 mg/kg/day, particularly those not receiving enzyme-inducing drugs, should be monitored more closely. If the total daily dose exceeds 250 mg, it should be given in a divided regimen. There is no experience with more rapid infusions in patients receiving DEPACON as replacement therapy. However, the equivalence shown between DEPACON and oral valproate products (DEPAKOTE) at steady state was only evaluated in an every 6 hour regimen. Whether, when DEPACON is given less frequently (i.e., twice or three times a day), trough levels fall below those that result from an oral dosage form given via the same regimen, is unknown. For this reason, when DEPACON is given twice or three times a day, close monitoring of trough plasma levels may be needed.

General Dosing Advice

Dosing in Elderly Patients

Due to a decrease in unbound clearance of valproate and possibly a greater sensitivity to somnolence in the elderly, the starting dose should be reduced in these patients. Dosage should be increased more slowly and with regular monitoring for fluid and nutritional intake, dehydration, somnolence, and other adverse events. Dose reductions or discontinuation of valproate should be considered in patients with decreased food or fluid intake and in patients with excessive somnolence. The ultimate therapeutic dose should be achieved on the basis of both tolerability and clinical response (see WARNINGS).

Dose-Related Adverse Events

The frequency of adverse effects (particularly elevated liver enzymes and thrombocytopenia) may be dose-related. The probability of thrombocytopenia appears to increase significantly at total valproate concentrations of ≥ 110 µg/mL (females) or ≥ 135 µg/mL (males) (see PRECAUTIONS). The benefit of improved therapeutic effect with higher doses should be weighed against the possibility of a greater incidence of adverse reactions.

Administration

Rapid infusion of DEPACON has been associated with an increase in adverse events. There is limited experience with infusion times of less than 60 minutes or rates of infusion > 20 mg/min in patients with epilepsy (see ADVERSE REACTIONS).

DEPACON should be administered intravenously as a 60 minute infusion, as noted above. It should be diluted with at least 50 mL of a compatible diluent. Any unused portion of the vial contents should be discarded.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit.

Compatibility and Stability

DEPACON was found to be physically compatible and chemically stable in the following parenteral solutions for at least 24 hours when stored in glass or polyvinyl chloride (PVC) bags at controlled room temperature 15-30°C (59-86°F).

  • dextrose (5%) injection, USP
  • sodium chloride (0.9%) injection, USP
  • lactated ringer's injection, USP

HOW SUPPLIED

DEPACON (valproate sodium injection), equivalent to 100 mg of valproic acid per mL, is a clear, colorless solution in 5 mL single-dose vials, available in trays of 10 vials (NDC  0074-1564-10).

Recommended storage: Store vials at controlled room temperature 15-30°C (59-86°F). No preservatives have been added. Unused portion of container should be discarded.

Manufactured at
Hospira, Inc.
McPherson, KS 67460 USA

Manufactured by
Hospira, Inc.
Lake Forest, IL 60045 USA

For

Abbott Laboratories

North Chicago, IL 60064, U.S.A.

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