Sodium valproate

Main article: Valproic acid

Sodium valproate

Systematic (IUPAC) name
sodium 2-propylpentanoate
Clinical data
AHFS/Drugs.com	monograph
MedlinePlus	a682412
Pregnancy cat.	D(AU) D(US)
Legal status	℞ Prescription only
Routes	Oral, i.v.
Pharmacokinetic data
Protein binding	90–95%
Metabolism	75% by CYP enzymes
Half-life	9–18 hours
Excretion	20% excreted as glucuronide
Identifiers
CAS number	1069-66-5 Y
ATC code	N03AG01
PubChem	CID 14047
ChemSpider	13428 Y
UNII	5VOM6GYJ0D Y
KEGG	D00710 Y
ChEBI	CHEBI:9925 N
ChEMBL	CHEMBL433 Y
Chemical data
Formula	C8H15NaO2
Mol. mass	166.20 g/mol
SMILES	eMolecules & PubChem
InChI InChI=1S/C8H16O2.Na/c1-3-5-7(6-4-2)8(9)10;/h7H,3-6H2,1-2H3,(H,9,10);/q;+1/p-1 Y Key:AEQFSUDEHCCHBT-UHFFFAOYSA-M Y
N(what is this?)  valproate (verify)

Sodium valproate (INN) or valproate sodium (USAN) is the sodium salt of valproic acid and is an anticonvulsant used in the treatment of epilepsy, anorexia nervosa, panic attack, anxiety disorder, posttraumatic stress disorder, migraine and bipolar disorder, as well as other psychiatric conditions requiring the administration of a mood stabilizer. Sodium valproate can be used to control acute episodes of mania and acute stress reaction. Side effects can include tiredness, tremors, nausea, vomiting and sedation.^[1] The intravenous formulations are used when oral administration is not possible.

In pregnancy, valproate has the highest risk of birth defects of any of the commonly-used antiepilepsy drugs. However, some epilepsy can only be controlled by valproate, and seizures also pose grave risk to mother and child.

Some of the common adverse effects include: tiredness, tremor, sedation and gastrointestinal disturbances. In addition, about 10% of the users experience reversible hair loss. ^[2]

Formulations

Trade names are in bold, followed by the manufacturer.

U.S.

• Intravenous injection – Depacon by Abbott Laboratories.
• Syrup – Depakene by Abbott Laboratories. (Note Depakene capsules are valproic acid).
• Depakote tablets are a mixture of sodium valproate and valproic acid.

Australia

• Epilim Crushable Tablets Sanofi-Aventis
• Epilim Sugar Free Liquid Sanofi-Aventis
• Epilim Syrup Sanofi-Aventis
• Epilim Tablets Sanofi-Aventis
• Sodium Valproate Sandoz Tablets Sanofi-Aventis
• Valpro Tablets Alphapharm
• Valproate Winthrop Tablets Sanofi-Aventis

UK

• Tablets – Orlept by Wockhardt and Epilim by Sanofi-Aventis.
• Oral solution – Orlept Sugar Free by Wockhardt and Epilim by Sanofi-Aventis.
• Syrup – Epilim by Sanofi-Aventis.
• Intravenous injection – Epilim Intravenous by Sanofi-Aventis.
• Extended release tablets – Epilim Chrono by Sanofi-Aventis. A combination of sodium valproate and valproic acid in a 2.3:1 ratio.
• Enteric-coated tablets – Epilim EC200 by Sanofi-synthélabo. A 200 mg sodium valproate enteric-coated tablet.

UK only

• Capsules – Episenta prolonged release by Beacon.
• Sachets – Episenta prolonged release by Beacon.
• Intravenous solution for injection – Episenta solution for injection by Beacon.

Germany, Switzerland, Norway, Finland

• Tablets – Orfiril by Desitin Pharmaceuticals
• Intravenous injection – Orfiril IV by Desitin Pharmaceuticals

South Africa

• Syrup – Convulex by Byk Madaus
• Tablets – Epilim by sanofi~synthelabo

Canada

• Intravenous injection – Epival or Epiject by Abbott Laboratories.
• Syrup – Depakene by Abbott Laboratories. Generic formulations include Apo-Valproic and ratio-Valproic.

Japan

• Tablets – Depakene by Kyowa Hakko Kirin.
• Extended release tablets – Depakene-R by Kyowa Hakko Kogyo and Selenica-R by Kowa.
• Syrup – Depakene by Kyowa Hakko Kogyo.

Europe

In much of Europe, Depakine and Depakine Chrono (tablets) are equivalent to Epilim and Epilim Chrono above.

Taiwan

• Tablets (white round tablet) – Depakine (Chinese: 帝拔癲; pinyin: di-ba-dian) by Sanofi Winthrop Industrie (France).

Safety in pregnancy

The risk of birth defects with valproate is two to five times higher than other frequently-used anti-epileptic drugs (absolute rates of birth defects 6-11%). Children born to mothers using valproate have significantly lower I.Q. scores (9 points). However, some epilepsy can only be controlled by valproate, and seizures during pregnancy can have grave consequences for both mother and child. Doctors recommend that women who intend to become pregnant should be switched to a different drug using combined therapy if possible, which takes several months. Women who are already pregnant and taking a high dose of valproate should try to lower their dose.^[3][4][5]

All antiepileptic medications have been shown to be associated with higher risks of fetal abnormalities (mostly for spina bifida) since at least 1983 with the risks being related to the strength of medication used and use of more than one drug^[6][7]

Valproate has also been recognised as sometimes causing a specific facial changes ("facial phenotype") termed "fetal valproate syndrome".^[8] Sodium valproate has been associated with the rare condition paroxysmal tonic upgaze of childhood, also known as Ouvrier-Billson syndrome, from childhood or fetal exposure (this condition resolved after discontinuing valproate therapy.^[9][10]

While developmental delay is usually associated with altered physical characteristics (dysmorphic features), this is not always the case.^[11]

A 2005 study found rates of autism among children exposed to sodium valproate before birth in the cohort studied were 8.9%.^[12] The normal incidence for autism in the general population is estimated at less than one percent.^[13] It has been suggested that Valproate may best be avoided in women with localisation epilepsy, where there are more effective and less risky alternatives such as carbamazepine.^[11] A 2008 study ^[14] also suggested a correlation between higher rates of autism in children whose mothers were treated for seizure disorders during pregnancy using sodium valproate (less than 1% for children who didn't receive the drug in vitro vs. 6.3% for children who did). However, only 632 children were followed in this study, prompting criticism that this study was too small to rely on to say whether there was a definitive correlation between the use of sodium valproate in pregnant mothers and higher autism rates in their children, or whether other anti-seizure medications used during pregnancy don't cause this effect.

One multi-centre trial in the UK and US looked at cognitive function in 309 children born to mothers with epilepsy and found that sodium valproate-use was associated with an IQ level eight points lower in children born to mothers taking sodium valproate than mothers taking other anti-epileptic drugs.^[15] The authors of the study attempted to correct for confounding factors, but this is an observational study, and therefore cannot prove a causal link. It should be noted, however, that to prove a causal link requires a randomised-controlled trial, which is not possible to perform.^[16] It is therefore unlikely that any stronger evidence will become available.

A class action is currently underway in the United Kingdom regarding the claim that the drug used in pregnancy caused a range of problems in children, including autism, learning and social difficulties, ADHD, spinal stenosis,^[specify] facial abnormalities, vision defects, dyslexia, dyspraxia, delayed speech and motor development.^[17][18][19]

See also

• Valproate semisodium

References

1. ^ Gelder, M., Mayou, R., Geddes, J. (2006) Psychiarty. 3rd edition. Oxford: Oxford University Press
2. ^ Gelder, M, Mayou, R. and Geddes, J. 2005. Psychiatry. 3rd ed. New York: Oxford. pp250.
3. ^ I.Q. Harmed by Epilepsy Drug in Utero By RONI CARYN RABIN, New York Times, April 15, 2009
4. ^ Cognitive function at 3 years of age after fetal exposure to antiepileptic drugs, Kimford J. Meador et al. for the NEAD Study Group, N Engl J Med 360:1597 April 16, 2009
5. ^ Which drug for the pregnant woman with epilepsy? Torbjorn Tomson, N Engl J Med 360:1597 April 16, 2009
6. ^ Koch S, Göpfert-Geyer I, Jäger-Roman E, et al. (February 1983). "[Anti-epileptic agents during pregnancy. A prospective study on the course of pregnancy, malformations and child development]" (in German). Dtsch. Med. Wochenschr. 108 (7): 250–7. doi:10.1055/s-2008-1069536. PMID 6402356. 
7. ^ Moore SJ, Turnpenny P, Quinn A, et al. (July 2000). "A clinical study of 57 children with fetal anticonvulsant syndromes". J. Med. Genet. 37 (7): 489–97. doi:10.1136/jmg.37.7.489. PMC 1734633. PMID 10882750. http://jmg.bmj.com/cgi/pmidlookup?view=long&pmid=10882750. 
8. ^ DiLiberti JH, Farndon PA, Dennis NR, Curry CJ (November 1984). "The fetal valproate syndrome". Am. J. Med. Genet. 19 (3): 473–81. doi:10.1002/ajmg.1320190308. PMID 6439041. 
9. ^ Epileptic Disord. 2007 Sep; 9(3):332-6
10. ^ J Child Neurol. 1988 Jul;3(3):177-80
11. ^ ^{a b} Adab N, Kini U, Vinten J, et al. (November 2004). "The longer term outcome of children born to mothers with epilepsy". J. Neurol. Neurosurg. Psychiatr. 75 (11): 1575–83. doi:10.1136/jnnp.2003.029132. PMC 1738809. PMID 15491979. http://jnnp.bmj.com/cgi/content/full/75/11/1575. "This argues that the fetal valproate syndrome constitutes a real clinical entity that includes developmental delay and cognitive impairments, but that some children might exhibit some developmental delay without marked dysmorphism." 
12. ^ Rasalam AD, Hailey H, Williams JH, et al. (August 2005). "Characteristics of fetal anticonvulsant syndrome associated autistic disorder". Dev Med Child Neurol 47 (8): 551–5. doi:10.1017/S0012162205001076. PMID 16108456. http://www.blackwell-synergy.com/openurl?genre=article&sid=nlm:pubmed&issn=0012-1622&date=2005&volume=47&issue=8&spage=551. 
13. ^ Autism Society of America: About Autism
14. ^ Bromley L, Mawer G, Clayton-Smith J, Baker GA, et al. (December 2008). "Autism spectrum disorders following in utero exposure to antiepileptic drugs". Neurology 71 (23): 1923–4. doi:10.1212/01.wnl.0000339399.64213.1a. PMID 19047565. http://www.neurology.org/cgi/content/full/71/23/1923. 
15. ^ Meador KJ, Baker GA, Browning N, et al. (2009). "Cognitive function at 3 years of age after fetal exposure to antiepileptic drugs". N Engl J Med 360 (16): 1597–1605. doi:10.1056/NEJMoa0803531. PMC 2737185. PMID 19369666. http://content.nejm.org/cgi/content/abstract/360/16/1597?ijkey=40a3bc71b9fbaf20b868a2f9bff104523ac6b696&keytype2=tf_ipsecsha. 
16. ^ Tomson T (2009). "Which drug for the pregnant woman with epilepsy?". N Engl J Med 360 (16): 1667–1669. doi:10.1056/NEJMe0901550. PMID 19369673. http://content.nejm.org/cgi/content/full/360/16/1667. 
17. ^ Families Sue Europe’s Largest Drug Company Over Anti-Convulsant Drug as Deadline Is Given By High Court
18. ^ "Legal action over Epilim". Epilepsy Action. 24 April 2007. http://www.epilepsy.org.uk/node/1149. Retrieved 15 April 2009. 
19. ^ Brimelow A (1 October 2004). "Women sue over epilepsy drug risk". BBC News. http://news.bbc.co.uk/2/hi/health/3705384.stm. Retrieved 15 April 2009. 

External links

• Chemical Land21: Sodium Valproate
• RXList.com: Depacon (Sodium Valproate)
• British National Formulary Edition 58
• Med Broadcast.com: Epival
• Drugs.com: Depaken Syrup