Overview
11 DESCRIPTION Divalproex sodium is a stable co-ordination compound comprised of sodium valproate and valproic acid in a 1:1 molar relationship and formed during the partial neutralization of valproic acid with 0.5 equivalent of sodium hydroxide. Chemically it is designated as sodium hydrogen bis(2-propylpentanoate).
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Divalproex sodium dissociates to the valproate ion in the gastrointestinal tract. The mechanisms by which valproate exerts its therapeutic effects have not been established. It has been suggested that its activity in epilepsy is related to increased brain concentrations of gamma-aminobutyric acid (GABA). 12.2 Pharmacodynamics The relationship between plasma concentration and clinical response is not well documented. One contributing factor is the nonlinear, concentration dependent protein binding of valproate which affects the clearance of the drug. Thus, monitoring of total serum valproate may not provide a reliable index of the bioactive valproate species.
Indications
- 1 INDICATIONS AND USAGE Divalproex sodium extended-release tablets are indicated for: • Acute treatment of manic or mixed episodes associated with bipolar disorder, with or without psychotic features ( 1.1 ) • Monotherapy and adjunctive therapy of complex partial seizures and simple and complex absence seizures; adjunctive therapy in patients with multiple seizure types that include absence seizures ( 1.2 ) • Prophylaxis of migraine headaches ( 1.3 ) 1.
Common Doses
- 25 mg
- 60 mg
- 15 mg
- 10 mg
Dosage
2 DOSAGE AND ADMINISTRATION Divalproex sodium extended-release tablets are an extended-release product intended for once-a-day oral administration. Divalproex sodium extended-release tablets should be swallowed whole and should not be crushed or chewed. • Divalproex sodium extended-release tablets are intended for once-a-day oral administration. Divalproex sodium extended-release tablets should be swallowed whole and should not be crushed or chewed ( 2.1 , 2.2 ).
Black Box Warning
WARNING: LIFE THREATENING ADVERSE REACTIONS Hepatotoxicity General Population: Hepatic failure resulting in fatalities has occurred in patients receiving valproate and its derivatives. These incidents usually have occurred during the first six months of treatment. Serious or fatal hepatotoxicity may be preceded by non-specific symptoms such as malaise, weakness, lethargy, facial edema, anorexia, and vomiting. In patients with epilepsy, a loss of seizure control may also occur. Patients should be monitored closely for appearance of these symptoms.
Contraindications
- 4 CONTRAINDICATIONS Divalproex sodium extended-release tablets are contraindicated in patients: • with hepatic disease or significant hepatic dysfunction [see Warnings and Precautions (5.1) ] . • known to have mitochondrial disorders caused by mutations in mitochondrial DNA polymerase γ (POLG; e.g., Alpers-Huttenlocher Syndrome) and children under two years of age who are suspected of having a POLG-related disorder [see Warnings and Precautions (5.1) ] . • with known hypersensitivity to divalproex sodium, sodium valproate, or valproic acid.
Side Effects
- 6 ADVERSE REACTIONS The following serious adverse reactions are described below and elsewhere in the labeling: • Hepatic Failure [see Warnings and Precautions (5.1) ] • Birth Defects [see Warnings and Precautions (5.2) ] • Decreased IQ and Neurodevelopmental Disorders following in utero exposure [see Warnings and Precautions (5.3) ] • Pancreatitis [see Warnings and Precautions (5.5) ] • Hyperammonemic Encephalopathy [see Warnings and Precautions (5.6 , 5.9 , 5.10) ] • Suicidal Behavior and Ideation [see Warnings and Precautions (5.
Interactions
- 7 DRUG INTERACTIONS • Hepatic enzyme-inducing drugs (e.g., phenytoin, carbamazepine, phenobarbital, primidone, rifampin) can increase valproate clearance, while enzyme inhibitors (e.g., felbamate) can decrease valproate clearance. Therefore, increased monitoring of valproate and concomitant drug concentrations and dosage adjustment are indicated whenever enzyme-inducing or inhibiting drugs are introduced or withdrawn ( 7.1 ) • Aspirin, carbapenem antibiotics, estrogen-containing hormonal contraceptives, methotrexate: Monitoring of valproate concentrations is recommended ( 7.