Valproic acid

Valproic acid
Black Box Warning
Adult Indications & Dosage
Pediatric Indications & Dosage
Contraindications
Warnings & Precautions
Adverse Reactions
Drug Interactions
Use in Specific Populations
Administration & Monitoring
Overdosage
Pharmacology
Clinical Studies
How Supplied
Images
Patient Counseling Information
Precautions with Alcohol
Brand Names
Look-Alike Names

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Pratik Bahekar, MBBS [2]

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Black Box Warning

WARNING: LIFE THREATENING ADVERSE REACTIONS See full prescribing information for complete Boxed Warning. Condition Name: Hepatotoxicity General Population: 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 [see Warnings and Precautions]. Children under the age of two years are at a considerably increased risk of developing fatal hepatotoxicity, especially those on multiple anticonvulsants, those with congenital metabolic disorders, those with severe seizure disorders accompanied by mental retardation, and those with organic brain disease. When Depakene 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. The incidence of fatal hepatotoxicity decreases considerably in progressively older patient groups. Patients with Mitochondrial Disease: There is an increased risk of valproate-induced acute liver failure and resultant deaths in patients with hereditary neurometabolic syndromes caused by DNA mutations of the mitochondrial DNA Polymerase γ (POLG) gene (e.g. Alpers Huttenlocher Syndrome). Depakene 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]. In patients over two years of age who are clinically suspected of having a hereditary mitochondrial disease, Depakene should only be used after other anticonvulsants have failed. This older group of patients should be closely monitored during treatment with Depakene for the development of acute liver injury with regular clinical assessments and serum liver testing. POLG mutation screening should be performed in accordance with current clinical practice [see Warnings and Precautions]. Fetal Risk Valproate can cause major congenital malformations, particularly neural tube defects (e.g., spina bifida). In addition, valproate can cause decreased IQ scores following in utero exposure. Valproate should only be used to treat pregnant women with epilepsy if other medications have failed to control their symptoms or are otherwise unacceptable. Valproate should not be administered to a woman of childbearing potential unless the drug is essential to the management of her medical condition. This is especially important when valproate use is considered for a condition not usually associated with permanent injury or death (e.g., migraine). Women should use effective contraception while using valproate [see Warnings and Precautions]. A Medication Guide describing the risks of valproate is available for patients [see Patient Counseling Information ]. Pancreatitis Cases of life-threatening pancreatitis have been reported in both children and adults receiving valproate. Some of the cases have been described as hemorrhagic with a rapid progression from initial symptoms to death. Cases have been reported shortly after initial use as well as after several years of use. Patients and guardians should be warned that abdominal pain, nausea, vomiting, and/or anorexia can be symptoms of pancreatitis that require prompt medical evaluation. If pancreatitis is diagnosed, valproate should ordinarily be discontinued. Alternative treatment for the underlying medical condition should be initiated as clinically indicated [see Warnings and Precautions].

Overview

Valproic acid is a anticonvulsant drug that is FDA approved for the {{{indicationType}}} of absence seizure, Simple and complex, complex partial epileptic seizur, manic, bipolar I disorder, migraine; Prophylaxis. There is a Black Box Warning for this drug as shown here. Common adverse reactions include peripheral edema,alopecia, rash, increased appetite, weight increased, abdominal pain, constipation, diarrhea, indigestion, loss of appetite, nausea, vomiting, ecchymosis, sthenia, backache, amnesia, ataxia, dizziness, headache, insomnia, somnolence, tremor, amblyopia, blurred vision, diplopia, nystagmus, tinnitus, depression, disturbance in thinking, feeling nervous, mood swings, bronchitis, dyspnea, pharyngitis, respiratory tract infection, rhinitis, fever, influenza.

Adult Indications and Dosage

FDA-Labeled Indications and Dosage (Adult)

• Absence seizure, simple and complex

• Initial 15 mg/kg/day PO in 2 to 3 divided doses if total daily dose exceeds 250 mg
• Maintenance increase dosage 5 to 10 mg/kg/day PO at 1-week intervals give in 2 to 3 divided doses if total daily dose exceeds 250 mg max 60 mg/kg/day or less with a therapeutic serum range of 50 to 100 mcg/mL

• Complex partial epileptic seizure

• Initial 10 to 15 mg/kg/day PO in 2 to 3 divided doses if total daily dose exceeds 250 mg, increase dosage 5 to 10 mg/kg/day at 1-week intervals to achieve optimal respons max 60 mg/kg/day or less with a therapeutic serum range of 50 to 100 mcg/mL
• Conversion to monotherapy, 10 to 15 mg/kg/day PO in 2 to 3 divided doses if total daily dose exceeds 250 mg, increase dosage 5 to 10 mg/kg/day at 1-week intervals to achieve optimal clinical response max 60 mg/kg/day or less with a therapeutic serum range of 50 to 100 mcg/mL
• Adjunct may be added to the regimen at an initial dosage of 10 to 15 mg/kg/day PO in 2 to 3 divided doses if total daily dose exceeds 250 mg, increase dosage 5 to 10 mg/kg/day at 1-week intervals to achieve optimal clinical response max 60 mg/kg/day or less.

• Manic bipolar I disorder

• Initial, delayed-release 750 mg PO daily, in divided doses; may increase dose to achieve desired clinical response max 60 mg/kg/day or less

• Migraine Prophylaxis

• Delayed-release 250 mg PO twice daily, max dose 1000 mg/day

Off-Label Use and Dosage (Adult)

Guideline-Supported Use

There is limited information about Off-Label Guideline-Supported Use of Valproic acid in adult patients.

Non–Guideline-Supported Use

• Alcohol hallucinosis
• Bipolar disorder
• Myelodysplastic syndrome
• Myoclonic seizure

There is limited information about Off-Label Non–Guideline-Supported Use of Valproic acid in adult patients.

Pediatric Indications and Dosage

FDA-Labeled Indications and Dosage (Pediatric)

• Risk of fatal hepatotoxicity in patients under the age of 2 years
• Absence seizure, Simple and complexfor 2.5 to 13 years

• 10 mg/kg/day for 2 weeks, 15 mg/kg/day for weeks 3 and 4, 20 mg/kg/day for weeks 5 and 6, 30 mg/kg/day for weeks 7 and 8, 40 mg/kg/day for weeks 9 and 10, 50 mg/kg/day for weeks 11 and 12, 60 mg/kg/day for weeks 13 through 16; max dose 60 mg/kg/day or 3000 mg/day, whichever lower, mean dose, 34.9 mg/kg/day
• For 10 years or older, initial, 15 mg/kg/day PO give in 2 to 3 divided doses if dose exceeds 250 mg, maintenance 5 to 10 mg/kg/day PO 1-week intervals until seizures are controlled or side effects preclude further increases in 2 to 3 divided doses if total daily dose exceeds 250 mg max 60 mg/kg/day or less with a therapeutic serum range of 50 to 100 mcg/mL

• Complex partial epileptic seizure 10 years or older

• Monotherapy, initial 10 to 15 mg/kg/day PO give in 2 to 3 divided doses if total daily dose exceeds 250 mg, may increase dosage 5 to 10 mg/kg/day at 1-week intervals to achieve optimal clinical response max 60 mg/kg/day or less
• conversion to monotherapy, 10 to 15 mg/kg/day ORALLY (give in 2 to 3 divided doses if total daily dose exceeds 250 mg), may increase dosage 5 to 10 mg/kg/day at 1-week intervals to achieve optimal clinical response max 60 mg/kg/day or less
• Adjunct, may be added to the regimen at an initial dosage of 10 to 15 mg/kg/day PO in 2 to 3 divided doses if total daily dose exceeds 250 mg, may increase dosage 5 to 10 mg/kg/day at 1-week intervals to achieve optimal clinical response max 60 mg/kg/day.

Off-Label Use and Dosage (Pediatric)

Guideline-Supported Use

There is limited information about Off-Label Guideline-Supported Use of Valproic acid in pediatric patients.

Non–Guideline-Supported Use

There is limited information about Off-Label Non–Guideline-Supported Use of Valproic acid in pediatric patients.

Contraindications

There is limited information regarding Valproic acid Contraindications in the drug label.

Warnings

WARNING: LIFE THREATENING ADVERSE REACTIONS See full prescribing information for complete Boxed Warning. Condition Name: Hepatotoxicity General Population: 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 [see Warnings and Precautions]. Children under the age of two years are at a considerably increased risk of developing fatal hepatotoxicity, especially those on multiple anticonvulsants, those with congenital metabolic disorders, those with severe seizure disorders accompanied by mental retardation, and those with organic brain disease. When Depakene 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. The incidence of fatal hepatotoxicity decreases considerably in progressively older patient groups. Patients with Mitochondrial Disease: There is an increased risk of valproate-induced acute liver failure and resultant deaths in patients with hereditary neurometabolic syndromes caused by DNA mutations of the mitochondrial DNA Polymerase γ (POLG) gene (e.g. Alpers Huttenlocher Syndrome). Depakene 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]. In patients over two years of age who are clinically suspected of having a hereditary mitochondrial disease, Depakene should only be used after other anticonvulsants have failed. This older group of patients should be closely monitored during treatment with Depakene for the development of acute liver injury with regular clinical assessments and serum liver testing. POLG mutation screening should be performed in accordance with current clinical practice [see Warnings and Precautions]. Fetal Risk Valproate can cause major congenital malformations, particularly neural tube defects (e.g., spina bifida). In addition, valproate can cause decreased IQ scores following in utero exposure. Valproate should only be used to treat pregnant women with epilepsy if other medications have failed to control their symptoms or are otherwise unacceptable. Valproate should not be administered to a woman of childbearing potential unless the drug is essential to the management of her medical condition. This is especially important when valproate use is considered for a condition not usually associated with permanent injury or death (e.g., migraine). Women should use effective contraception while using valproate [see Warnings and Precautions]. A Medication Guide describing the risks of valproate is available for patients [see Patient Counseling Information ]. Pancreatitis Cases of life-threatening pancreatitis have been reported in both children and adults receiving valproate. Some of the cases have been described as hemorrhagic with a rapid progression from initial symptoms to death. Cases have been reported shortly after initial use as well as after several years of use. Patients and guardians should be warned that abdominal pain, nausea, vomiting, and/or anorexia can be symptoms of pancreatitis that require prompt medical evaluation. If pancreatitis is diagnosed, valproate should ordinarily be discontinued. Alternative treatment for the underlying medical condition should be initiated as clinically indicated [see Warnings and Precautions].

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. 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 Depakene 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 Depakene 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. 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, opthalmoplegia, 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, Depakene should only be used after other anticonvulsants have failed. This older group of patients should be closely monitored during treatment with Depakene 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.

Birth Defects

Valproate can cause fetal harm when administered to a pregnant woman. Pregnancy registry data show that maternal valproate use can cause neural tube defects and other structural abnormalities (e.g., craniofacial defects, cardiovascular malformations and malformations involving various body systems). The rate of congenital malformations among babies born to mothers using valproate is about four times higher than the rate among babies born to epileptic mothers using other anti-seizure monotherapies. Evidence suggests that folic acid supplementation prior to conception and during the first trimester of pregnancy decreases the risk for congenital neural tube defects in the general population.

Decreased IQ Following in utero Exposure

Valproate can cause decreased IQ scores following in utero exposure. Published epidemiological studies have indicated that children exposed to valproate in utero have lower cognitive test scores than children exposed in utero to either another antiepileptic drug or to no antiepileptic drugs. The largest of these studies1 is a prospective cohort study conducted in the United States and United Kingdom that found that children with prenatal exposure to valproate (n=62) had lower IQ scores at age 6 (97 [95% C.I. 94-101]) than children with prenatal exposure to the other antiepileptic drug monotherapy treatments evaluated: lamotrigine (108 [95% C.I. 105-110]), carbamazepine (105 [95% C.I. 102-108]), and phenytoin (108 [95% C.I. 104-112]). It is not known when during pregnancy cognitive effects in valproate-exposed children occur. Because the women in this study were exposed to antiepileptic drugs throughout pregnancy, whether the risk for decreased IQ was related to a particular time period during pregnancy could not be assessed. Although all of the available studies have methodological limitations, the weight of the evidence supports the conclusion that valproate exposure in utero can cause decreased IQ in children. In animal studies, offspring with prenatal exposure to valproate had malformations similar to those seen in humans and demonstrated neurobehavioral deficits. Women with epilepsy who are pregnant or who plan to become pregnant should not be treated with valproate unless other treatments have failed to provide adequate symptom control or are otherwise unacceptable. In such women, the benefits of treatment with valproate during pregnancy may still outweigh the risks.

Use in Women of Childbearing Potential

Because of the risk to the fetus of decreased IQ and major congenital malformations (including neural tube defects), which may occur very early in pregnancy, valproate should not be administered to a woman of childbearing potential unless the drug is essential to the management of her medical condition. This is especially important when valproate use is considered for a condition not usually associated with permanent injury or death (e.g., migraine). Women should use effective contraception while using valproate. Women who are planning a pregnancy should be counseled regarding the relative risks and benefits of valproate use during pregnancy, and alternative therapeutic options should be considered for these patients. To prevent major seizures, valproate should not be discontinued abruptly, as this can precipitate status epilepticus with resulting maternal and fetal hypoxia and threat to life. Evidence suggests that folic acid supplementation prior to conception and during the first trimester of pregnancy decreases the risk for congenital neural tube defects in the general population. It is not known whether the risk of neural tube defects or decreased IQ in the offspring of women receiving valproate is reduced by folic acid supplementation. Dietary folic acid supplementation both prior to conception and during pregnancy should be routinely recommended for patients using valproate.

Pancreatitis

Cases of life-threatening pancreatitis have been reported in both children and adults receiving valproate. Some of the cases have been described as hemorrhagic with rapid progression from initial symptoms to death. Some cases have occurred shortly after initial use as well as after several years of use. The rate based upon the reported cases exceeds that expected in the general population and there have been cases in which pancreatitis recurred after rechallenge with valproate. In clinical trials, there were 2 cases of pancreatitis without alternative etiology in 2416 patients, representing 1044 patient-years experience. Patients and guardians should be warned that abdominal pain, nausea, vomiting, and/or anorexia can be symptoms of pancreatitis that require prompt medical evaluation. If pancreatitis is diagnosed, valproate should ordinarily be discontinued. Alternative treatment for the underlying medical condition should be initiated as clinically indicated.

Urea Cycle Disorders (UCD)

Valproic acid is contraindicated in patients with known urea cycle disorders. Hyperammonemic encephalopathy, sometimes fatal, has been reported following initiation of valproate therapy in patients with urea cycle disorders, a group of uncommon genetic abnormalities, particularly ornithine transcarbamylase deficiency. Prior to the initiation of valproate therapy, evaluation for UCD should be considered in the following patients-1) those with a history of unexplained encephalopathy or coma, encephalopathy associated with a protein load, pregnancy-related or postpartum encephalopathy, unexplained mental retardation, or history of elevated plasma ammonia or glutamine; 2) those with cyclical vomiting and lethargy, episodic extreme irritability, ataxia, low BUN, or protein avoidance; 3) those with a family history of UCD or a family history of unexplained infant deaths (particularly males); 4) those with other signs or symptoms of UCD. Patients who develop symptoms of unexplained hyperammonemic encephalopathy while receiving valproate therapy should receive prompt treatment (including discontinuation of valproate therapy) and be evaluated for underlying urea cycle disorders.

Brain Atrophy

There have been postmarketing reports of reversible and irreversible cerebral and cerebellar atrophy temporally associated with the use of valproate products; in some cases, patients recovered with permanent sequelae. The motor and cognitive functions of patients on valproate should be routinely monitored and drug should be evaluated for continued use in the presence of suspected or apparent signs of brain atrophy. Reports of cerebral atrophy have also been reported in children who were exposed in children who were exposed in utero to valproate products.

Suicidal Behavior and Ideation

Antiepileptic drugs (AEDs), including Depakene, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior. Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide. The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed. The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5-100 years) in the clinical trials analyzed.

The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications. Anyone considering prescribing Depakene or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated. Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.

Thrombocytopenia

The frequency of adverse effects (particularly elevated liver enzymes and thrombocytopenia may be dose-related. In a clinical trial of Depakote (divalproex sodium) as monotherapy in patients with epilepsy, 34/126 patients (27%) receiving approximately 50 mg/kg/day on average, had at least one value of platelets ≤ 75 x 109/L. Approximately half of these patients had treatment discontinued, with return of platelet counts to normal. In the remaining patients, platelet counts normalized with continued treatment. In this study, the probability of thrombocytopenia appeared to increase significantly at total valproate concentrations of ≥ 110 mcg/mL (females) or ≥ 135 mcg/mL (males). The therapeutic benefit which may accompany the higher doses should therefore be weighed against the possibility of a greater incidence of adverse effects. Because of reports of thrombocytopenia, inhibition of the secondary phase of platelet aggregation, and abnormal coagulation parameters, (e.g., low fibrinogen), platelet counts and coagulation tests are recommended before initiating therapy and at periodic intervals. It is recommended that patients receiving Depakene (valproic acid) be monitored for platelet count and coagulation parameters prior to planned surgery. Evidence of hemorrhage, bruising, or a disorder of hemostasis/coagulation is an indication for reduction of the dosage or withdrawal of therapy.

Hyperammonemia

Hyperammonemia has been reported in association with valproate therapy and may be present despite normal liver function tests. In patients who develop unexplained lethargy and vomiting or changes in mental status, hyperammonemic encephalopathy should be considered and an ammonia level should be measured. Hyperammonemia should also be considered in patients who present with hypothermia. If ammonia is increased, valproate therapy should be discontinued. Appropriate interventions for treatment of hyperammonemia should be initiated, and such patients should undergo investigation for underlying urea cycle disorders. Asymptomatic elevations of ammonia are more common and when present, require close monitoring of plasma ammonia levels. If the elevation persists, discontinuation of valproate therapy should be considered.

Hyperammonemia and Encephalopathy Associated with Concomitant Topiramate Use

Concomitant administration of topiramate and valproate has been associated with hyperammonemia with or without encephalopathy in patients who have tolerated either drug alone. Clinical symptoms of hyperammonemic encephalopathy often include acute alterations in level of consciousness and/or cognitive function with lethargy or vomiting. Hypothermia can also be a manifestation of hyperammonemia . In most cases, symptoms and signs abated with discontinuation of either drug. This adverse reaction is not due to a pharmacokinetic interaction. It is not known if topiramate monotherapy is associated with hyperammonemia. Patients with inborn errors of metabolism or reduced hepatic mitochondrial activity may be at an increased risk for hyperammonemia with or without encephalopathy. Although not studied, an interaction of topiramate and valproate may exacerbate existing defects or unmask deficiencies in susceptible persons. In patients who develop unexplained lethargy, vomiting, or changes in mental status, hyperammonemic encephalopathy should be considered and an ammonia level should be measured.

Hypothermia

Hypothermia, defined as an unintentional drop in body core temperature to <35°C (95°F), has been reported in association with valproate therapy both in conjunction with and in the absence of hyperammonemia. This adverse reaction can also occur in patients using concomitant topiramate with valproate after starting topiramate treatment or after increasing the daily dose of topiramate. Consideration should be given to stopping valproate in patients who develop hypothermia, which may be manifested by a variety of clinical abnormalities including lethargy, confusion, coma, and significant alterations in other major organ systems such as the cardiovascular and respiratory systems. Clinical management and assessment should include examination of blood ammonia levels.

Multi-Organ Hypersensitivity Reactions

Multi-organ hypersensitivity reactions have been rarely reported in close temporal association to the initiation of valproate therapy in adult and pediatric patients (median time to detection 21 days: range 1 to 40 days). Although there have been a limited number of reports, many of these cases resulted in hospitalization and at least one death has been reported. Signs and symptoms of this disorder were diverse; however, patients typically, although not exclusively, presented with fever and rash associated with other organ system involvement. Other associated manifestations may include lymphadenopathy, hepatitis, liver function test abnormalities, hematological abnormalities (e.g., eosinophilia, thrombocytopenia, neutropenia), pruritus, nephritis, oliguria, hepato-renal syndrome, arthralgia, and asthenia. Because the disorder is variable in its expression, other organ system symptoms and signs, not noted here, may occur. If this reaction is suspected, valproate should be discontinued and an alternative treatment started. Although the existence of cross sensitivity with other drugs that produce this syndrome is unclear, the experience amongst drugs associated with multi-organ hypersensitivity would indicate this to be a possibility.

Interaction with Carbapenem Antibiotics

Carbapenem antibiotics (for example, ertapenem, imipenem, meropenem; this is not a complete list) may reduce serum valproate concentrations to subtherapeutic levels, resulting in loss of seizure control. Serum valproate concentrations should be monitored frequently after initiating carbapenem therapy. Alternative antibacterial or anticonvulsant therapy should be considered if serum valproate concentrations drop significantly or seizure control deteriorates.

Somnolence in the Elderly

In a double-blind, multicenter trial of valproate in elderly patients with dementia (mean age = 83 years), doses were increased by 125 mg/day to a target dose of 20 mg/kg/day. A significantly higher proportion of valproate patients had somnolence compared to placebo, and although not statistically significant, there was a higher proportion of patients with dehydration. Discontinuations for somnolence were also significantly higher than with placebo. In some patients with somnolence (approximately one-half), there was associated reduced nutritional intake and weight loss. There was a trend for the patients who experienced these events to have a lower baseline albumin concentration, lower valproate clearance, and a higher BUN. In elderly patients, dosage should be increased more slowly and with regular monitoring for fluid and nutritional intake, dehydration, somnolence, and other adverse reactions. Dose reductions or discontinuation of valproate should be considered in patients with decreased food or fluid intake and in patients with excessive somnolence.

Monitoring- Drug Plasma Concentration

Since valproate may interact with concurrently administered drugs which are capable of enzyme induction, periodic plasma concentration determinations of valproate and concomitant drugs are recommended during the early course of therapy.

Effect on Ketone and Thyroid Function Tests

Valproate is partially eliminated in the urine as a keto-metabolite which may lead to a false interpretation of the urine ketone test. There have been reports of altered thyroid function tests associated with valproate. The clinical significance of these is unknown.

Effect on HIV and CMV Viruses Replication

There are in vitro studies that suggest valproate stimulates the replication of the HIV and CMV viruses under certain experimental conditions. The clinical consequence, if any, is not known. Additionally, the relevance of these in vitro findings is uncertain for patients receiving maximally suppressive antiretroviral therapy. Nevertheless, these data should be borne in mind when interpreting the results from regular monitoring of the viral load in HIV infected patients receiving valproate or when following CMV infected patients clinically.

Adverse Reactions

Clinical Trials Experience

There is limited information regarding Valproic acid Clinical Trials Experience in the drug label.

Postmarketing Experience

There is limited information regarding Valproic acid Postmarketing Experience in the drug label.

Drug Interactions

There is limited information regarding Valproic acid Drug Interactions in the drug label.

Use in Specific Populations

Pregnancy

Pregnancy Category (FDA): There is no FDA guidance on usage of Valproic acid in women who are pregnant.
Pregnancy Category (AUS): There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Valproic acid in women who are pregnant.

Labor and Delivery

There is no FDA guidance on use of Valproic acid during labor and delivery.

Nursing Mothers

There is no FDA guidance on the use of Valproic acid in women who are nursing.

Pediatric Use

There is no FDA guidance on the use of Valproic acid in pediatric settings.

Geriatic Use

There is no FDA guidance on the use of Valproic acid in geriatric settings.

Gender

There is no FDA guidance on the use of Valproic acid with respect to specific gender populations.

Race

There is no FDA guidance on the use of Valproic acid with respect to specific racial populations.

Renal Impairment

There is no FDA guidance on the use of Valproic acid in patients with renal impairment.

Hepatic Impairment

There is no FDA guidance on the use of Valproic acid in patients with hepatic impairment.

Females of Reproductive Potential and Males

There is no FDA guidance on the use of Valproic acid in women of reproductive potentials and males.

Immunocompromised Patients

There is no FDA guidance one the use of Valproic acid in patients who are immunocompromised.

Administration and Monitoring

Administration

There is limited information regarding Valproic acid Administration in the drug label.

Monitoring

There is limited information regarding Valproic acid Monitoring in the drug label.

IV Compatibility

There is limited information regarding the compatibility of Valproic acid and IV administrations.

Overdosage

There is limited information regarding Valproic acid overdosage. If you suspect drug poisoning or overdose, please contact the National Poison Help hotline (1-800-222-1222) immediately.

Pharmacology

Valproic acid
Systematic (IUPAC) name
2-Propylpentanoic acid
Identifiers
CAS number	99-66-1
ATC code	N03AG01
PubChem	3121
DrugBank	DB00313
Chemical data
Formula	Template:OrganicBox atomTemplate:OrganicBox atomTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBox atomTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBoxTemplate:OrganicBox
Mol. mass	144.211 g/mol
SMILES	eMolecules & PubChem
Synonyms	2-Propylvaleric acid
Pharmacokinetic data
Bioavailability	Rapid absorption
Protein binding	80-90%
Metabolism	Hepatic—glucuronide conjugation 30–50%, mitochondrial β-oxidation over 40%
Half life	9–16 hours
Excretion	Urine (30-50%)
Therapeutic considerations
Licence data	US
Pregnancy cat.	D(AU) X(US)
Legal status	Prescription Only (S4)(AU) ?(CA) POM(UK) [[Prescription drug|Template:Unicode-only]](US)
Routes	Oral, intravenous

Mechanism of Action

There is limited information regarding Valproic acid Mechanism of Action in the drug label.

Structure

There is limited information regarding Valproic acid Structure in the drug label.

Pharmacodynamics

There is limited information regarding Valproic acid Pharmacodynamics in the drug label.

Pharmacokinetics

There is limited information regarding Valproic acid Pharmacokinetics in the drug label.

Nonclinical Toxicology

There is limited information regarding Valproic acid Nonclinical Toxicology in the drug label.

Clinical Studies

There is limited information regarding Valproic acid Clinical Studies in the drug label.

How Supplied

There is limited information regarding Valproic acid How Supplied in the drug label.

Storage

There is limited information regarding Valproic acid Storage in the drug label.

Images

Drug Images

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Package and Label Display Panel

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Patient Counseling Information

There is limited information regarding Valproic acid Patient Counseling Information in the drug label.

Precautions with Alcohol

Alcohol-Valproic acid interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

Brand Names

There is limited information regarding Valproic acid Brand Names in the drug label.

Look-Alike Drug Names

There is limited information regarding Valproic acid Look-Alike Drug Names in the drug label.

Drug Shortage Status

Price

References

The contents of this FDA label are provided by the National Library of Medicine.