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Trade names | Depakote, Epilim, Convulex, others |
Other names | VPA; valproic acid; sodium valproate (sodium); valproate semisodium (semisodium); 2-propylvaleric acid |
AHFS/Drugs.com | Monograph |
MedlinePlus | a682412 |
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Routes of administration | By mouth, intravenous |
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Pharmacokinetic data | |
Bioavailability | Rapid absorption |
Protein binding | 80–90% [6] |
Metabolism | Liver—glucuronide conjugation 30–50%, mitochondrial β-oxidation over 40% |
Elimination half-life | 9–16 hours [6] |
Excretion | Urine (30–50%) [6] |
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ECHA InfoCard | 100.002.525 |
Chemical and physical data | |
Formula | C8H16O2 |
Molar mass | 144.214 g·mol−1 |
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Valproate (valproic acid, VPA, sodium valproate, and valproate semisodium forms) are medications primarily used to treat epilepsy and bipolar disorder and prevent migraine headaches. [7] They are useful for the prevention of seizures in those with absence seizures, partial seizures, and generalized seizures. [7] They can be given intravenously or by mouth, and the tablet forms exist in both long- and short-acting formulations. [7]
Common side effects of valproate include nausea, vomiting, somnolence, and dry mouth. [7] Serious side effects can include liver failure, and regular monitoring of liver function tests is therefore recommended. [7] Other serious risks include pancreatitis and an increased suicide risk. [7] Valproate is known to cause serious abnormalities or birth defects in the unborn child if taken during pregnancy, [7] [8] and is contra-indicated for women of childbearing age unless the drug is essential to their medical condition and the person is also prescribed a contraceptive. [7] [9] [4] Reproductive warnings have also been issued for men using the drug. [10] The United States Food and Drug Administration has indicated a black box warning given the frequency and severity of the side effects and teratogenicity. [4] Additionally, there is also a black box warning due to risk of hepatotoxicity and pancreatitis. [11] As of 2022 the drug was still prescribed in the UK to potentially pregnant women, but use declined by 51% from 2018–19 to 2020–21. [12]
Valproate's precise mechanism of action is unclear. [7] [13] Proposed mechanisms include affecting GABA levels, blocking voltage-gated sodium channels, inhibiting histone deacetylases, and increasing LEF1. [14] [15] [16] Valproic acid is a branched short-chain fatty acid (SCFA), a derivative of valeric acid. [14]
Valproate was originally synthesized in 1881 and came into medical use in 1962. [17] It is on the World Health Organization's List of Essential Medicines. [18] It is available as a generic medication. [7] In 2022, it was the 174th most commonly prescribed medication in the United States, with more than 2 million prescriptions. [19] [20]
Valproate or valproic acid is used primarily to treat epilepsy and bipolar disorder and to prevent migraine headaches. [21]
Valproate has a broad spectrum of anticonvulsant activity, although it is primarily used as a first-line treatment for tonic–clonic seizures, absence seizures and myoclonic seizures and as a second-line treatment for partial seizures and infantile spasms. [21] [22] It has also been successfully given intravenously to treat status epilepticus. [23] [24]
In the US, valproic acid is also prescribed as an anti-epileptic drug indicated for the treatment of manic episodes associated with bipolar disorder; monotherapy and adjunctive therapy of complex partial seizures and simple and complex absence seizures; adjunctive therapy in people with multiple seizure types that include absence seizures. [4] [5]
Valproate products are used to treat manic or mixed episodes of bipolar disorder. [25] [26]
A 2016 systematic review compared the efficacy of valproate as an add-on for people with schizophrenia: [27]
There is limited evidence that adding valproate to antipsychotics may be effective for overall response and also for specific symptoms, especially in terms of excitement and aggression. Valproate was associated with a number of adverse events among which sedation and dizziness appeared more frequently than in the control groups. [27] | ||||||||||||||||||||||||||||||||||||||||||||||||
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Based upon five case reports, valproic acid may have efficacy in controlling the symptoms of the dopamine dysregulation syndrome that arise from the treatment of Parkinson's disease with levodopa. [28] [29] [30]
Valproate is not commonly used to prevent or treat migraine headaches, but it may be prescribed if other medications are effective. [31]
The medication has been tested in the treatment of AIDS and cancer, owing to its histone-deacetylase-inhibiting effects.[ citation needed ] It has cardioprotective, kidney protective, antiinflammatory, and antimicrobial effects. [32]
Contraindications include:
Most common adverse effects include: [4]
Serious adverse effects include: [4]
Valproic acid has a black box warning for hepatotoxicity, pancreatitis, and fetal abnormalities. [4]
There is evidence that valproic acid may cause premature growth plate ossification in children and adolescents, resulting in decreased height. [36] [37] [38] Valproic acid can also cause mydriasis, a dilation of the pupils. [39] There is evidence that shows valproic acid may increase the chance of polycystic ovary syndrome (PCOS) in women with epilepsy or bipolar disorder. Studies have shown this risk of PCOS is higher in women with epilepsy compared to those with bipolar disorder. [40] Weight gain is also possible. [41]
Valproate may cause increased somnolence in the elderly. In a trial of valproate in elderly patients with dementia, a significantly higher portion of valproate patients had somnolence compared to placebo. In approximately one-half of such patients, there was associated reduced nutritional intake and weight loss. [4]
Form | Lower limit | Upper limit | Unit |
Total (including protein bound) | 50 [45] | 125 [45] | μg/mL or mg/L |
350 [46] | 700 [46] | μmol/L | |
Free | 6 [45] | 22 [45] | μg/mL or mg/L |
35 [46] | 70 [46] | μmol/L |
Excessive amounts of valproic acid can result in somnolence, tremor, stupor, respiratory depression, coma, metabolic acidosis, and death. In general, serum or plasma valproic acid concentrations are in a range of 20–100 mg/L during controlled therapy, but may reach 150–1500 mg/L following acute poisoning. Monitoring of the serum level is often accomplished using commercial immunoassay techniques, although some laboratories employ gas or liquid chromatography. [47] In contrast to other antiepileptic drugs, at present there is little favorable evidence for salivary therapeutic drug monitoring. Salivary levels of valproic acid correlate poorly with serum levels, partly due to valproate's weak acid property (pKa of 4.9). [48]
In severe intoxication, hemoperfusion or hemofiltration can be an effective means of hastening elimination of the drug from the body. [49] [50] Supportive therapy should be given to all patients experiencing an overdose and urine output should be monitored. [4] Supplemental L-carnitine is indicated in patients having an acute overdose [51] [52] and also prophylactically [51] in high risk patients. Acetyl-L-carnitine lowers hyperammonemia less markedly [53] than L-carnitine.
Valproate inhibits CYP2C9, glucuronyl transferase, and epoxide hydrolase and is highly protein bound and hence may interact with drugs that are substrates for any of these enzymes or are highly protein bound themselves. [33] It may also potentiate the CNS depressant effects of alcohol. [33] It should not be given in conjunction with other antiepileptics due to the potential for reduced clearance of other antiepileptics (including carbamazepine, lamotrigine, phenytoin and phenobarbitone) and itself. [33] It may also interact with: [4] [33] [54]
Although the mechanism of action of valproate is not fully understood, [33] traditionally, its anticonvulsant effect has been attributed to the blockade of voltage-gated sodium channels and increased brain levels of the inhibitory synaptic neurotransmitter gamma-aminobutyric acid (GABA). [33] The GABAergic effect is also believed to contribute towards the anti-manic properties of valproate. [33] In animals, sodium valproate raises cerebral and cerebellar levels of GABA, possibly by inhibiting GABA degradative enzymes, such as GABA transaminase, succinate-semialdehyde dehydrogenase and by inhibiting the re-uptake of GABA by neuronal cells. [33] Prevention of neurotransmitter-induced hyperexcitability of nerve cells via Kv7.2 channel and AKAP5 may also contribute to its mechanism. [55] Valproate has been shown to protect against a seizure-induced reduction in phosphatidylinositol (3,4,5)-trisphosphate (PIP3) as a potential therapeutic mechanism. [56]
Valproate is a histone deacetylase inhibitor. By inhibition of histone deacetylase, it promotes more transcriptionally active chromatin structures, that is it exerts an epigenetic effect. This has been proven in mice: Valproic acid induced histone hyperacetylation had brain function effects on the next generation of mice through changes in sperm DNA methylation. [57] Intermediate molecules include VEGF, BDNF, and GDNF. [58] [59]
Valproic acid has been found to be an antagonist of the androgen and progesterone receptors, and hence as a nonsteroidal antiandrogen and antiprogestogen, at concentrations much lower than therapeutic serum levels. [60] In addition, the drug has been identified as a potent aromatase inhibitor, and suppresses estrogen concentrations. [61] These actions are likely to be involved in the reproductive endocrine disturbances seen with valproic acid treatment. [60] [61]
Valproic acid has been found to directly stimulate androgen biosynthesis in the gonads via inhibition of histone deacetylases and has been associated with hyperandrogenism in women and increased 4-androstenedione levels in men. [62] [63] High rates of polycystic ovary syndrome and menstrual disorders have also been observed in women treated with valproic acid. [63]
Taken by mouth, valproate is rapidly and virtually completely absorbed from the gut. [64] When in the bloodstream, 80–90% of the substance are bound to plasma proteins, mainly albumin. Protein binding is saturable: it decreases with increasing valproate concentration, low albumin concentrations, the patient's age, additional use of other drugs such as aspirin, as well as liver and kidney impairment. [66] [67] Concentrations in the cerebrospinal fluid and in breast milk are 1 to 10% of blood plasma concentrations. [64]
The vast majority of valproate metabolism occurs in the liver. [68] Valproate is known to be metabolized by the cytochrome P450 enzymes CYP2A6, CYP2B6, CYP2C9, and CYP3A5. [68] It is also known to be metabolized by the UDP-glucuronosyltransferase enzymes UGT1A3, UGT1A4, UGT1A6, UGT1A8, UGT1A9, UGT1A10, UGT2B7, and UGT2B15. [68] Some of the known metabolites of valproate by these enzymes and uncharacterized enzymes include (see image): [68]
All in all, over 20 metabolites are known. [64]
In adult patients taking valproate alone, 30–50% of an administered dose is excreted in urine as the glucuronide conjugate. [68] The other major pathway in the metabolism of valproate is mitochondrial beta oxidation, which typically accounts for over 40% of an administered dose. [68] Typically, less than 20% of an administered dose is eliminated by other oxidative mechanisms. [68] Less than 3% of an administered dose of valproate is excreted unchanged (i.e., as valproate) in urine. [68] Only a small amount is excreted via the faeces. [64] Elimination half-life is 16±3 hours and can decrease to 4–9 hours when combined with enzyme inducers. [64] [67]
Valproic acid is a branched short-chain fatty acid and the 2-n-propyl derivative of valeric acid. [14]
Valproic acid was first synthesized in 1882 by Beverly S. Burton as an analogue of valeric acid, found naturally in valerian. [69] Valproic acid is a carboxylic acid, a clear liquid at room temperature. For many decades, its only use was in laboratories as a "metabolically inert" solvent for organic compounds. In 1962, the French researcher Pierre Eymard serendipitously discovered the anticonvulsant properties of valproic acid while using it as a vehicle for a number of other compounds that were being screened for antiseizure activity. He found it prevented pentylenetetrazol-induced convulsions in laboratory rats. [70] It was approved as an antiepileptic drug in 1967 in France and has become the most widely prescribed antiepileptic drug worldwide. [71] Valproic acid has also been used for migraine prophylaxis and bipolar disorder. [72]
Valproate is available as a generic medication. [7]
This section needs to be updated.(February 2024) |
Indications | FDA-labelled indication? [6] | TGA-labelled indication? [21] | MHRA-labelled indication? [73] | Literature support |
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Epilepsy | Yes | Yes | Yes | Limited (depends on the seizure type; it can help with certain kinds of seizures: drug-resistant epilepsy, partial and absence seizures, can be used against glioblastoma and other tumors both to improve survival and treat seizures, and against tonic–clonic seizures and status epilepticus). [74] [75] [76] [77] |
Bipolar mania | Yes | Yes | Yes | Limited. [78] [ failed verification ] |
Bipolar depression | No | No | No | Moderate. [79] |
Bipolar maintenance | No | No | No | Limited. [80] |
Migraine prophylaxis | Yes | Yes (accepted) | No | Limited. |
Acute migraine management | No | No | No | Only negative results. [81] |
Schizophrenia | No | No | No | Weak evidence. [82] |
Agitation in dementia | No | No | No | Weak evidence. Not recommended for agitation in people with dementia. [83] Increased rate of adverse effects, including a risk of serious adverse effects. [83] |
Fragile X syndrome | Yes (orphan) | No | No | Limited. [59] |
Familial adenomatous polyposis | Yes (orphan) | No | No | Limited. |
Chronic pain & fibromyalgia | No | No | No | Limited. [84] |
Alcohol hallucinosis | No | No | No | One randomised double-blind placebo-controlled trial. [85] |
Intractable hiccups | No | No | No | Limited, five case reports support its efficacy, however. [86] |
Non-epileptic myoclonus | No | No | No | Limited, three case reports support its efficacy, however. [87] |
Cluster headaches | No | No | No | Limited, two case reports support its efficacy. [88] |
West syndrome | No | No | No | A prospective clinical trial supported its efficacy in treating infantile spasms. [89] |
HIV infection eradication | No | No | No | Double-blind placebo-controlled trials have been negative. [90] [91] [92] |
Myelodysplastic syndrome | No | No | No | Several clinical trials have confirmed its efficacy as a monotherapy, [93] as an adjunct to tretinoin [93] and as an adjunct to hydralazine. [94] |
Acute myeloid leukaemia | No | No | No | Two clinical trials have confirmed its efficacy in this indication as both a monotherapy and as an adjunct to tretinoin. [95] [96] [97] |
Cervical cancer | No | No | No | One clinical trial supports its use here. [98] |
Malignant melanoma | No | No | No | One phase II study has seemed to discount its efficacy. [99] |
Breast cancer | No | No | No | A phase II study has supported its efficacy. [100] |
Impulse control disorder | No | No | No | Limited. [101] [102] |
In 2012, pharmaceutical company Abbott paid $1.6 billion in fines to US federal and state governments for illegal promotion of off-label uses for Depakote, including the sedation of elderly nursing home residents. [103] [104]
Some studies have suggested that valproate may reopen the critical period for learning absolute pitch and possibly other skills such as language. [105] [106]
Clinical data | |
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Other names | valproate sodium (USAN US) |
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ECHA InfoCard | 100.002.525 |
Chemical and physical data | |
Formula | C8H15NaO2 |
Molar mass | 166.196 g·mol−1 |
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Trade names | Depakote, others | ||
Other names | semisodium valproate, divalproex sodium (USAN US) | ||
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ECHA InfoCard | 100.002.525 | ||
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Formula | C16H31NaO4 | ||
Molar mass | 310.410 g·mol−1 | ||
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Valproate exists in two main molecular variants: sodium valproate and valproic acid without sodium (often implied by simply valproate). A mixture between these two is termed semisodium valproate. It is unclear whether there is any difference in efficacy between these variants, except from the fact that about 10% more mass of sodium valproate is needed than valproic acid without sodium to compensate for the sodium itself. [109]
Valproate is a negative ion. The conjugate acid of valproate is valproic acid (VPA). Valproic acid is fully ionized into valproate at the physiologic pH of the human body, and valproate is the active form of the drug. Sodium valproate is the sodium salt of valproic acid. Divalproex sodium is a coordination complex composed of equal parts of valproic acid and sodium valproate. [110]
Branded products include:
In much of Europe, Dépakine and Depakine Chrono (tablets) are equivalent to Epilim and Epilim Chrono above.
Depalept and Depalept Chrono (extended release tablets) are equivalent to Epilim and Epilim Chrono above. Manufactured and distributed by Sanofi-Aventis.
A 2023 systematic review of the literature identified only one study in which valproate was evaluated in the treatment of seizures in infants aged 1 to 36 months. In a randomized control trial, valproate alone was found to show poorer outcomes for infants than valproate plus levetiracetam in terms of reduction of seizures, freedom from seizures, daily living ability, quality of life, and cognitive abilities. [117]
Carbamazepine, sold under the brand name Tegretol among others, is an anticonvulsant medication used in the treatment of epilepsy and neuropathic pain. It is used as an adjunctive treatment in schizophrenia along with other medications and as a second-line agent in bipolar disorder. Carbamazepine appears to work as well as phenytoin and valproate for focal and generalized seizures. It is not effective for absence or myoclonic seizures.
A mood stabilizer is a psychiatric medication used to treat mood disorders characterized by intense and sustained mood shifts, such as bipolar disorder and the bipolar type of schizoaffective disorder.
Anticonvulsants are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder and borderline personality disorder, since many seem to act as mood stabilizers, and for the treatment of neuropathic pain. Anticonvulsants suppress the excessive rapid firing of neurons during seizures. Anticonvulsants also prevent the spread of the seizure within the brain.
Ertapenem, sold under the brand name Invanz, is a carbapenem antibiotic medication used for the treatment of infections of the abdomen, the lungs, the upper part of the female reproductive system, and the diabetic foot.
Lamotrigine, sold under the brand name Lamictal among others, is a medication used to treat epilepsy and stabilize mood in bipolar disorder. For epilepsy, this includes focal seizures, tonic-clonic seizures, and seizures in Lennox-Gastaut syndrome. In bipolar disorder, lamotrigine has not been shown to reliably treat acute depression in any groups except for the severely depressed; but for patients with bipolar disorder who are not currently symptomatic, it appears to reduce the risk of future episodes of depression.
Absence seizures are one of several kinds of generalized seizures. In the past, absence epilepsy was referred to as "pyknolepsy," a term derived from the Greek word "pyknos," signifying "extremely frequent" or "grouped". These seizures are sometimes referred to as petit mal seizures ; however, usage of this terminology is no longer recommended. Absence seizures are characterized by a brief loss and return of consciousness, generally not followed by a period of lethargy. Absence seizures are most common in children. They affect both sides of the brain.
Oxcarbazepine, sold under the brand name Trileptal among others, is a medication used to treat epilepsy. For epilepsy it is used for both focal seizures and generalized seizures. It has been used both alone and as add-on therapy in people with bipolar disorder who have had no success with other treatments. It is taken by mouth.
Levetiracetam, sold under the brand name Keppra among others, is a novel antiepileptic drug (medication) used to treat epilepsy. It is used for partial-onset, myoclonic, or tonic–clonic seizures, and is taken either by mouth as an immediate or extended release formulation or by injection into a vein.
Valpromide is a carboxamide derivative of valproic acid used in the treatment of epilepsy and some affective disorders. It is rapidly metabolised (80%) to valproic acid but has anticonvulsant properties itself. It may produce more stable plasma levels than valproic acid or sodium valproate and may be more effective at preventing febrile seizures. However, it is over one hundred times more potent as an inhibitor of liver microsomal epoxide hydrolase. This makes it incompatible with carbamazepine and can affect the ability of the body to remove other toxins. Valpromide is no safer during pregnancy than valproic acid.
Tiagabine is an anticonvulsant medication produced by Cephalon that is used in the treatment of epilepsy. The drug is also used off-label in the treatment of anxiety disorders and panic disorder.
Clobazam, sold under the brand names Frisium, Onfi and others, is a benzodiazepine class medication that was patented in 1968. Clobazam was first synthesized in 1966 and first published in 1969. Clobazam was originally marketed as an anxioselective anxiolytic since 1970, and an anticonvulsant since 1984. The primary drug-development goal was to provide greater anxiolytic, anti-obsessive efficacy with fewer benzodiazepine-related side effects.
Stiripentol, sold under the brand name Diacomit, is an anticonvulsant medication used for the treatment of Dravet syndrome - a serious genetic brain disorder.
Sodium phenylbutyrate, sold under the brand name Buphenyl among others, is a salt of an aromatic fatty acid, 4-phenylbutyrate (4-PBA) or 4-phenylbutyric acid. The compound is used to treat urea cycle disorders, because its metabolites offer an alternative pathway to the urea cycle to allow excretion of excess nitrogen.
The emphasis of the treatment of bipolar disorder is on effective management of the long-term course of the illness, which can involve treatment of emergent symptoms. Treatment methods include pharmacological and psychological techniques.
Histone deacetylase inhibitors are chemical compounds that inhibit histone deacetylases. Since deacetylation of histones produces transcriptionally silenced heterochromatin, HDIs can render chromatin more transcriptionally active and induce epigenomic changes.
Seletracetam is a pyrrolidone-derived drug of the racetam family that is structurally related to levetiracetam. It was under development by UCB Pharmaceuticals as a more potent and effective anticonvulsant drug to replace levetiracetam but its development has been halted.
Lacosamide, sold under the brand name Vimpat among others, is a medication used for the treatment of partial-onset seizures and primary generalized tonic-clonic seizures. It is used by mouth or intravenously.
Eslicarbazepine acetate (ESL), sold under the brand names Aptiom and Zebinix among others, is an anticonvulsant medication approved for use in Europe and the United States as monotherapy or as additional therapy for partial-onset seizures epilepsy.
Antimanic drugs are psychotropic drugs that are used to treat symptoms of mania. Though there are different causes of mania, the majority is caused by bipolar disorder, therefore antimanic drugs are mostly similar to drugs treating bipolar disorder. Since 1970s, antimanic drugs have been used specifically to control the abnormal elevation of mood or mood swings during manic episodes. One purpose of antimanic drugs is to alleviate or shorten the duration of an acute mania. Another objective is to prevent further cycles of mania and maintain the improvement achieved during the acute episode. The mechanism of antimanic drugs has not yet been fully known, it is proposed that they mostly affect chemical neurotransmitters in the brain. However, the usage of antimanic drugs should be consulted with a doctor or pharmacist due to their side effects and interactions with other drugs and food.
Fetal valproate spectrum disorder (FVSD), previously known as fetal valproate syndrome (FVS), is a rare disease caused by prenatal exposure to valproic acid (VPA), a medication commonly used to treat epilepsy, bipolar disorder, and migraines. This exposure can lead to a range of neurodevelopmental and physical symptoms, including cognitive impairments, developmental delays, autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and congenital malformations.