VALTAS OD-750MG

Indications

• Epilepsy
• Bipolar disorder
• Migraine prevention

Dosage

Children: Refer to the BNF for Children for specific pediatric dosing guidelines, which will depend on the child's age, weight, and condition.

Adults: Refer to the BNF for specific dosing information based on the condition being treated and patient characteristics.

Mechanism of action

Divaproex exerts its therapeutic effects primarily through the inhibition of voltage-gated sodium channels, leading to a decrease in neuronal excitability. Additionally, it enhances the activity of GABA, an inhibitory neurotransmitter, which contributes to its anticonvulsant and mood-stabilizing properties. By increasing GABA levels and modulating calcium channel activity, divaproex effectively reduces seizure frequency and stabilizes mood in patients with bipolar disorder.

Pharmacodynamics

Divaproex demonstrates a dose-dependent effect on the central nervous system, leading to a reduction in the frequency and severity of seizures and mood stabilization in bipolar disorder. Its efficacy in migraine prophylaxis is attributed to similar mechanisms involving the modulation of neurotransmitter release. The onset of action varies among conditions; for seizure control, it can take several days to weeks, while mood stabilization may take longer.

Pharmacokinetics

Divaproex is well absorbed after oral administration, with peak plasma concentrations typically occurring within 1-4 hours. The drug undergoes extensive hepatic metabolism, primarily through glucuronidation and beta-oxidation. The elimination half-life ranges from 9 to 16 hours, depending on individual metabolic factors. Divaproex is primarily excreted in urine as metabolites, with less than 5% excreted unchanged.

Contra-indications

• Hypersensitivity to divalproex or any component of the formulation
• Severe liver impairment
• Urea cycle disorders

Adverse effects

• Nausea
• Vomiting
• Drowsiness
• Dizziness
• Tremor
• Weight gain
• Alopecia
• Hepatotoxicity
• Pancreatitis
• Teratogenic effects

Interactions

• CNS depressants may enhance the sedative effect of divalproex
• Other antiepileptic drugs may alter the plasma concentration of divalproex
• Valproate may displace other drugs from protein binding sites, increasing their free concentrations

Precautions

• Monitor liver function tests prior to and during therapy
• Assess for signs of pancreatitis
• Monitor for signs of bleeding or bruising, indicating potential thrombocytopenia
• Consider potential teratogenic effects in women of childbearing potential

Pregnancy

Use during pregnancy is associated with an increased risk of congenital malformations and developmental delays. Consider alternative treatments where possible.

Breast-feeding

Divalproex is excreted in breast milk, but effects on the nursing infant are not well established. Weigh the benefits against potential risks.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Divalproex sodium delayed-release tablets
• Divalproex sodium extended-release tablets
• Divalproex sodium oral solution