Valproic Acid

1 INDICATIONS AND USAGE Valproic acid oral solution is indicated for: Monotherapy and adjunctive therapy of complex partial seizures; sole and adjunctive therapy of simple and complex absence seizures; adjunctive therapy in patients with multiple seizure types that include absence seizures ( 1 ) 1.1 Epilepsy Valproic acid oral solution 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. Valproic acid oral solution is indicated for use as sole and adjunctive therapy in the treatment of simple and complex absence seizures, and adjunctively in patients with multiple seizure types which 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 and Precautions ( 5.1 ) for statement regarding fatal hepatic dysfunction. 1.2 Important Limitations Because of the risk to the fetus of decreased IQ, neurodevelopmental disorders, neural tube defects, and other major congenital malformations, which may occur very early in pregnancy, valproate should not be used to treat women with epilepsy or bipolar disorder who are pregnant or who plan to become pregnant unless other medications have failed to provide adequate symptom control or are otherwise unacceptable. Valproate should not be administered to a woman of childbearing potential unless other medications have failed to provide adequate symptom control or are otherwise unacceptable [ see Warnings and Precautions ( 5.2 , 5.3 , 5.4 ), Use in Specific Populations ( 8.1 ), and Patient Counseling Information ( 17 ) ]. For prophylaxis of migraine headaches, valproate is contraindicated in women who are pregnant and in women of childbearing potential who are not using effective contraception [see Contraindications ( 4 )] .

2 DOSAGE AND ADMINISTRATION Valproic acid oral solution is intended for oral administration. ( 2.1 ) Simple and Complex Absence Seizures: Start at 10 to 15 mg/kg/day, increasing at 1 week intervals by 5 to 10 mg/kg/week until seizure control or limiting side effects ( 2.1 ) Safety of doses above 60 mg/kg/day is not established ( 2.1 , 2.2 ) 2.1 Epilepsy Valproic acid oral solution is intended for oral administration. Patients should be informed to take valproic acid oral solution every day as prescribed. If a dose is missed it should be taken as soon as possible, unless it is almost time for the next dose. If a dose is skipped, the patient should not double the next dose. Valproic acid oral solution is indicated as monotherapy and adjunctive therapy in complex partial seizures in adults and pediatric patients down to the age of 10 years, and in simple and complex absence seizures. As the valproic acid oral solution dosage is titrated upward, concentrations of clonazepam, diazepam, ethosuximide, lamotrigine, tolbutamide, phenobarbital, carbamazepine, and/or phenytoin may be affected [see Drug Interactions ( 7.2 ) ]. Complex Partial Seizures For adults and children 10 years of age or older. Monotherapy (Initial Therapy) Valproic acid oral solution 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 mcg/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 mcg/mL in females and 135 mcg/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 mcg/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 valproic acid oral solution 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 Valproic acid oral solution 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 mcg/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 divalproex sodium delayed-release …

5 WARNINGS AND PRECAUTIONS Hepatotoxicity; evaluate high risk populations and monitor serum liver tests ( 5.1 ) Birth defects, decreased IQ, and neurodevelopmental disorders following in utero exposure; should not be used to treat women with epilepsy or bipolar disorder who are pregnant or who plan to become pregnant or to treat a woman of childbearing potential unless other medications have failed to provide adequate symptom control or are otherwise unacceptable ( 5.2 , 5.3 , 5.4 ) Pancreatitis; valproic acid oral solution should ordinarily be discontinued ( 5.5 ) Suicidal behavior or ideation; Antiepileptic drugs, including valproic acid oral solution, increase the risk of suicidal thoughts or behavior ( 5.7 ) Bleeding and other hematopoietic disorders; monitor platelet counts and coagulation tests ( 5.8 ) Hyperammonemia and hyperammonemic encephalopathy; measure ammonia level if unexplained lethargy and vomiting or changes in mental status, and also with concomitant topiramate use; consider discontinuation of valproate therapy ( 5.6 , 5.9 , 5.10 ) Hypothermia; Hypothermia has been reported during valproate therapy with or without associated hyperammonemia. This adverse reaction can also occur in patients using concomitant topiramate ( 5.11 ) Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan hypersensitivity reaction; discontinue valproic acid oral solution ( 5.12 ) Somnolence in the elderly can occur. Valproic acid oral solution dosage should be increased slowly and with regular monitoring for fluid and nutritional intake ( 5.14 ) 5.1 Hepatotoxicity 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 valproic acid products are used in this patient group, they 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 Valproic acid oral solution is 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 …

4 CONTRAINDICATIONS Valproic acid oral solution should not be administered to patients with hepatic disease or significant hepatic dysfunction [see Warnings and Precautions ( 5.1 ) ]. Valproic acid oral solution is contraindicated in patients 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 ) ]. Valproic acid oral solution is contraindicated in patients with known hypersensitivity to the drug [see Warnings and Precautions ( 5.12 ) ]. Valproic acid oral solution is contraindicated in patients with known urea cycle disorders [see Warnings and Precautions ( 5.6 ) ]. For use in prophylaxis of migraine headaches: Valproic acid oral solution is contraindicated in women who are pregnant and in women of childbearing potential who are not using effective contraception [see Warnings and Precautions ( 5.2 , 5.3 , 5.4 ) and Use in Specific Populations ( 8.1 )]. Hepatic disease or significant hepatic dysfunction ( 4 , 5.1 ) Known mitochondrial disorders caused by mutations in mitochondrial DNA polymerase γ (POLG) ( 4 , 5.1 ) Suspected POLG-related disorder in children under two years of age ( 4 , 5.1 ) Known hypersensitivity to the drug ( 4 , 5.12 ) Urea cycle disorders ( 4 , 5.6 ) Prophylaxis of migraine headaches: Pregnant women, women of childbearing potential not using effective contraception ( 4 , 8.1 )

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: Monitoring of valproate concentrations is recommended ( 7.1 ) Co-administration of valproate can affect the pharmacokinetics of other drugs (e.g. diazepam, ethosuximide, lamotrigine, phenytoin) by inhibiting their metabolism or protein binding displacement ( 7.2 ) Patients stabilized on rufinamide should begin valproate therapy at a low dose, and titrate to clinically effective dose ( 7.2 ) Dosage adjustment of amitriptyline/nortriptyline, propofol, warfarin, and zidovudine may be necessary if used concomitantly with valproic acid oral solution ( 7.2 ) Topiramate: Hyperammonemia and encephalopathy ( 5.10 , 7.3 ) 7.1 Effects 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. 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 ) ]. Cholestyramine Cholestyramine, when concurrently administered with valproic acid, led to, on average, a 14% decrease in plasma levels of valproic acid in a study conducted in 6 healthy subjects administered valproic acid oral solution and cholestyramine. Delaying the administration of …

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 ( 5.7 ) ] 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. Most common adverse reactions (reported >5%) are abdominal pain, alopecia, amblyopia/blurred vision, amnesia, anorexia, asthenia, ataxia, bronchitis, constipation, depression, diarrhea, diplopia, dizziness, dyspepsia, dyspnea, ecchymosis, emotional lability, fever, flu syndrome, headache, increased appetite, infection, insomnia, nausea, nervousness, nystagmus, peripheral edema, pharyngitis, rhinitis, somnolence, thinking abnormal, thrombocytopenia, tinnitus, tremor, vomiting, weight gain, weight loss. ( 6.1 ) The safety and tolerability of valproate in pediatric patients were shown to be comparable to those in adults ( 8.4 ). To report SUSPECTED ADVERSE REACTIONS, contact Chartwell RX, LLC. 1-845-232-1683 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch 6.1 Epilepsy The data described in the following section were obtained using divalproex sodium delayed-release tablets. Based on a placebo-controlled trial of adjunctive therapy for treatment of complex partial seizures, divalproex sodium 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-treated patients (6%), compared to 1% of placebo-treated patients. Table 3 lists treatment-emergent adverse reactions which were reported by ≥ 5% of divalproex sodium- treated patients and for which the incidence was greater than in the placebo group, in a placebo- controlled trial of adjunctive therapy for treatment of complex partial seizures. Since patients were also treated with other antiepilepsy drugs, it is not possible, in most cases, to determine whether the following adverse reactions can be ascribed to divalproex sodium alone, or the combination of divalproex sodium and other antiepilepsy drugs. Table 3. Adverse Reactions Reported by ≥ 5% of Patients Treated with Divalproex Sodium During Placebo-Controlled Trial of Adjunctive Therapy for Complex Partial Seizures Body System/Reaction Divalpoex Sodium (n = 77) (%) Placebo (n = 70) (%) Body as a Whole Headache 31 21 Asthenia 27 7 Fever 6 4 Gastrointestinal System Nausea 48 14 Vomiting 27 7 Abdominal Pain 23 6 Diarrhea 13 6 Anorexia 12 0 Dyspepsia 8 4 Constipation 5 1 Nervous System Somnolence 27 11 Tremor 25 6 Dizziness 25 13 Diplopia 16 9 Amblyopia/Blurred Vision 12 9 Ataxia 8 1 Nystagmus 8 1 Emotional Lability 6 4 Thinking Abnormal 6 0 Amnesia 5 1 Respiratory System Flu Syndrome 12 9 Infection 12 6 Bronchitis 5 1 Rhinitis 5 4 Other Alopecia 6 1 Weight Loss 6 0 Table 4 lists treatment-emergent adverse reactions which were reported by ≥ 5% of patients in the high dose divalproex sodium group, and for which the incidence was greater than in the low dose group, in a controlled trial of divalproex sodium monotherapy treatment of complex partial seizures. Since patients were being titra…