Divalproex Sodium ER 500 mg Tablet, Extended Release, 60-count — NDC 72189-459-60 (Billing 72189-0459-60)

5.1Hepatotoxicity General Information on Hepatotoxicity Hepatic failure resulting in fatalities has occurred in patients receiving valproate. 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. Serum liver tests should be performed prior to therapy and at frequent intervals thereafter, especially during the first six months of valproate therapy.

However, healthcare providers should not rely totally on serum biochemistry since these tests may not be abnormal in all instances, but should also consider the results of careful interim medical history and physical examination. Caution should be observed when administering valproate products to patients with a prior history of hepatic disease. Patients on multiple anticonvulsants, children, those with congenital metabolic disorders, those with severe seizure disorders accompanied by mental retardation, and those with organic brain disease may be at particular risk.

See below, "Patients with Known or Suspected Mitochondrial Disease." Experience has indicated that children under the age of two years are at a considerably increased risk of developing fatal hepatotoxicity, especially those with the aforementioned conditions. When divalproex sodium extended-release tablets are used in this patient group, it should be used with extreme caution and as a sole agent. The benefits of therapy should be weighed against the risks.

In progressively older patient groups experience in epilepsy has indicated that the incidence of fatal hepatotoxicity decreases considerably. Patients with Known or Suspected Mitochondrial Disease Divalproex sodium extended-release tablets are contraindicated in patients known to have mitochondrial disorders caused by POLG mutations and children under two years of age who are clinically suspected of having a mitochondrial disorder [see Contraindications (4)]. Valproate-induced acute liver failure and liver-related deaths have been reported in patients with hereditary neurometabolic syndromes caused by mutations in the gene for mitochondrial DNA polymerase γ (POLG) (e.g., Alpers- Huttenlocher Syndrome) at a higher rate than those without these syndromes.

Most of the reported cases of liver failure in patients with these syndromes have been identified in children and adolescents. POLG-related disorders should be suspected in patients with a family history or suggestive symptoms of a POLG-related disorder, including but not limited to unexplained encephalopathy, refractory epilepsy (focal, myoclonic), status epilepticus at presentation, developmental delays, psychomotor regression, axonal sensorimotor neuropathy, myopathy cerebellar ataxia, ophthalmoplegia, or complicated migraine with occipital aura.

POLG mutation testing should be performed in accordance with current clinical practice for the diagnostic evaluation of such disorders. The A467T and W748S mutations are present in approximately 2/3 of patients with autosomal recessive POLG-related disorders. In patients over two years of age who are clinically suspected of having a hereditary mitochondrial disease, divalproex sodium extended-release tablets should only be used after other anticonvulsants have failed.

This older group of patients should be closely monitored during treatment with divalproex sodium extended-release tablets for the development of acute liver injury with regular clinical assessments and serum liver test monitoring. The drug should be discontinued immediately in the presence of significant hepatic dysfunction, suspected or apparent. In some cases, hepatic dysfunction has progressed in spite of discontinuation of drug [see BOXED WARNING and Contraindications (4)].

5.2Structural Birth De… [Excerpted — this section continues on DailyMed.]

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 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 (5.7)] Bleeding and other hematopoietic disorders [see Warnings and Precautions (5.8)] Hypothermia [see Warnings and Precautions (5.11)] Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan hypersensitivity reactions [see Warnings and Precautions (5.12)] Somnolence in the elderly [see Warnings and Precautions (5.14)] Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

Information on pediatric adverse reactions is presented in section 8.

6.1Mania The incidence of treatment-emergent events has been ascertained based on combined data from two three week placebo-controlled clinical trials of divalproex sodium extended-release tablets in the treatment of manic episodes associated with bipolar disorder. Table 3 summarizes those adverse reactions reported for patients in these trials where the incidence rate in the divalproex sodium extended-release tablet-treated group was greater than 5% and greater than the placebo incidence. Table 3.

Adverse Reactions Reported by > 5% of Divalproex Sodium Extended-Release Tablets-Treated Patients During Placebo-Controlled Trials of Acute Mania1 1The following adverse reactions/event occurred at an equal or greater incidence for placebo than for divalproex sodium extended-release tablets: headache Adverse Event Divalproex Sodium Extended-Release Tablets (n=338) % Placebo (n=263) % Somnolence 26 14 Dyspepsia 23 11 Nausea 19 13 Vomiting 13 5 Diarrhea 12 8 Dizziness 12 7 Pain 11 10 Abdominal Pain 10 5 Accidental Injury 6 5 Asthenia 6 5 Pharyngitis 6 5 The following additional adverse reactions were reported by greater than 1% of the divalproex sodium extended-release tablet-treated patients in controlled clinical trials: Body as a Whole: Back Pain, Chills, Chills and Fever, Drug Level Increased, Flu Syndrome, Infection, Infection Fungal, Neck Rigidity.

Cardiovascular System: Arrhythmia, Hypertension, Hypotension, Postural Hypotension. Digestive System: Constipation, Dry Mouth, Dysphagia, Fecal Incontinence, Flatulence, Gastroenteritis, Glossitis, Gum Hemorrhage, Mouth Ulceration. Hemic and Lymphatic System: Anemia, Bleeding Time Increased, Ecchymosis, Leucopenia.

Metabolic and Nutritional Disorders: Hypoproteinemia, Peripheral Edema. Musculoskeletal System: Arthrosis, Myalgia. Nervous System: Abnormal Gait, Agitation, Catatonic Reaction, Dysarthria, Hallucinations, Hypertonia, Hypokinesia, Psychosis, Reflexes Increased, Sleep Disorder, Tardive Dyskinesia, Tremor.

Respiratory System: Hiccup, Rhinitis. Skin and Appendages: Discoid Lupus Erythematosus, Erythema Nodosum, Furunculosis, Maculopapular Rash, Pruritus, Rash, Seborrhea, Sweating, Vesiculobullous Rash. Special Senses: Conjunctivitis, Dry Eyes, Eye Disorder, Eye Pain, Photophobia, Taste Perversion.

Urogenital System: Cystitis, Urinary Tract Infection, Menstrual Disorder, Vaginitis.

6.2Epilepsy Based on a placebo-controlled trial of adjunctive therapy for treatment of complex partial seizures, divalproex sodium delayed-release tablets was generally well tolerated with most adverse reactions rated as mild to moderate in severity. Intolerance was the primary reason for discontinuation in the divalproex sodium delayed-release tablet-treated patients (6%), compared to 1% of placebo-treated patients. Table 4 lists treatment-emergent adverse reactions which were repo… [Excerpted — this section continues on DailyMed.]

7.1Effects of Co-Administered Drugs on Valproate Clearance Drugs that affect the level of expression of hepatic enzymes, particularly those that elevate levels of glucuronosyltransferases (such as ritonavir), may increase the clearance of valproate. For example, phenytoin, carbamazepine, and phenobarbital (or primidone) can double the clearance of valproate. Thus, patients on monotherapy will generally have longer half-lives and higher concentrations than patients receiving polytherapy with antiepilepsy drugs.

In contrast, drugs that are inhibitors of cytochrome P450 isozymes, e.g., antidepressants, may be expected to have little effect on valproate clearance because cytochrome P450 microsomal mediated oxidation is a relatively minor secondary metabolic pathway compared to glucuronidation and beta-oxidation. Because of these changes in valproate clearance, monitoring of valproate and concomitant drug concentrations should be increased whenever enzyme inducing drugs are introduced or withdrawn. The following list provides information about the potential for an influence of several commonly prescribed medications on valproate pharmacokinetics.

The list is not exhaustive nor could it be, since new interactions are continuously being reported. Drugs for which a potentially important interaction has been observed Aspirin: A study involving the co-administration of aspirin at antipyretic doses (11 to 16 mg/kg) with valproate to pediatric patients (n=6) revealed a decrease in protein binding and an inhibition of metabolism of valproate. Valproate free fraction was increased 4-fold in the presence of aspirin compared to valproate alone.

The β-oxidation pathway consisting of 2-E-valproic acid, 3-OH- valproic acid, and 3-keto valproic acid was decreased from 25% of total metabolites excreted on valproate alone to 8.3% in the presence of aspirin. Whether or not the interaction observed in this study applies to adults is unknown, but caution should be observed if valproate and aspirin are to be co-administered. Carbapenem Antibiotics: A clinically significant reduction in serum valproic acid concentration has been reported in patients receiving carbapenem antibiotics (for example, ertapenem, imipenem, meropenem; this is not a complete list) and may result in loss of seizure control.

The mechanism of this interaction is not well understood. Serum valproic acid concentrations should be monitored frequently after initiating carbapenem therapy. Alternative antibacterial or anticonvulsant therapy should be considered if serum valproic acid concentrations drop significantly or seizure control deteriorates [see Warnings and Precautions (5.13)].

Estrogen-Containing Hormonal Contraceptives: Estrogen-containing hormonal contraceptives may increase the clearance of valproate, which may result in decreased concentration of valproate and potentially increased seizure frequency. Prescribers should monitor serum valproate concentrations and clinical response when adding or discontinuing estrogen containing products. Felbamate: A study involving the co-administration of 1,200 mg/day of felbamate with valproate to patients with epilepsy (n=10) revealed an increase in mean valproate peak concentration by 35% (from 86 to 115 mcg/mL) compared to valproate alone.

Increasing the felbamate dose to 2,400 mg/day increased the mean valproate peak concentration to 133 mcg/mL (another 16% increase). A decrease in valproate dosage may be necessary when felbamate therapy is initiated. Methotrexate: Methotrexate may decrease serum valproate levels and potentially result in increased frequency of seizures or bipolar symptoms.

Prescribers should monitor serum valproate concentrations and clinical response when adding or discontinuing methotrexate and adjust valproate dosage, if necessary. Rifampin: A study involving the administration of a single dose of valproate (7 mg/kg) 36 hours after 5 nights of daily dosing with rifampin (600 mg) revealed a 40% increase in the ora… [Excerpted — this section continues on DailyMed.]