Absence seizures
- Overview
- Theory
- Diagnosis
- Management
- Follow up
- Resources
Treatment algorithm
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer
typical absence seizures without a history of generalised tonic-clonic seizures (childhood absence epilepsy)
ethosuximide or valproic acid or lamotrigine
A patient with only typical absence seizures is likely to respond to ethosuximide, valproic acid, or lamotrigine as first-line treatments.[42]Glauser TA, Cnaan A, Shinnar S, et al. Ethosuximide, valproic acid, and lamotrigine in childhood absence epilepsy. N Engl J Med. 2010 Mar 4;362(9):790-9. https://www.nejm.org/doi/full/10.1056/NEJMoa0902014#t=article%E2%80%8B http://www.ncbi.nlm.nih.gov/pubmed/20200383?tool=bestpractice.com A Cochrane review concluded that ethosuximide is the optimal initial empirical monotherapy for children and adolescents with absence seizures.[41]Brigo F, Igwe SC, Lattanzi S. Ethosuximide, sodium valproate or lamotrigine for absence seizures in children and adolescents. Cochrane Database Syst Rev. 2019 Feb 8;2:CD003032. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD003032.pub4/full http://www.ncbi.nlm.nih.gov/pubmed/30734919?tool=bestpractice.com
In rare instances, ethosuximide can cause aplastic anaemia, and hepatic or renal failure.
Valproic acid can cause hepatotoxicity and pancreatitis, thrombocytopenia or pancytopenia, hyperammonaemia, fatigue, weight gain, and hair thinning. Periodic monitoring of FBCs and liver transaminases should be strongly considered. Trough drug levels can help with assessing compliance and effectiveness of therapy.
Valproic acid should be used with extreme caution in children aged younger than 2 years, due to increased risk of hepatotoxicity in this age group.
When initiating lamotrigine treatment, a slow titration is necessary to avoid Stevens-Johnson syndrome. Rare cases of hepatotoxicity or multi-organ failure have been reported. Adverse effects also include diplopia, ataxia, and insomnia.
Safety of anticonvulsants in pregnancy must be taken into account when choosing a suitable drug. Valproic acid and its derivatives may cause major congenital malformations, including neurodevelopmental disorders and neural tube defects, after in utero exposure.[52]Pack AM, Oskoui M, Williams Roberson S, et al. Teratogenesis, perinatal, and neurodevelopmental outcomes after in utero exposure to antiseizure medication: practice guideline from the AAN, AES, and SMFM. Neurology. 2024 Jun;102(11):e209279. https://www.neurology.org/doi/10.1212/WNL.0000000000209279?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed http://www.ncbi.nlm.nih.gov/pubmed/38748979?tool=bestpractice.com These drugs are contraindicated during pregnancy; however, if it is not possible to stop them, treatment may be continued with appropriate specialist care. Valproic acid and its derivatives must only be used in female patients of childbearing potential if certain precautionary measures are in place (e.g., only used if no suitable alternatives, a pregnancy prevention programme is in place); consult your local guidance for more information. Lamotrigine has not been associated with an increased risk of major congenital malformations or an increased risk of neurodevelopmental disorders or delay.[71]Medicines and Healthcare products Regulatory Agency. Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review. Apr 2022 [internet publication]. https://www.gov.uk/drug-safety-update/antiepileptic-drugs-in-pregnancy-updated-advice-following-comprehensive-safety-review A specialist should be consulted for more guidance on the use of specific drugs in pregnancy.
Primary options
ethosuximide: children 3-6 years of age: 15 mg/kg/day (maximum 250 mg) orally given in 2 divided doses initially, increase every 4-7 days according to response, usual maintenance dose is 15-40 mg/kg/day, maximum 1500 mg/day; children >6 years of age, adolescents and adults: refer to consultant for guidance on dosage
Secondary options
valproic acid: children <10 years of age: consult specialist for guidance on dose; adults and children ≥10 years of age: 15 mg/kg/day orally given in 1-3 divided doses initially, increase by 5-10 mg/kg/day increments every 7 days as tolerated and according to response
OR
lamotrigine: children and adults: consult specialist for guidance on dose
topiramate or zonisamide or levetiracetam
Second-line agents include topiramate, zonisamide, and levetiracetam.
Adverse effects of topiramate include word-finding difficulties or cognitive problems, weight loss, nephrolithiasis, and anhidrosis. Rarely, it can precipitate acute angle-closure glaucoma. Therefore, eye pain should be treated as an emergency.
Adverse effects of zonisamide include cognitive slowing, abdominal pain, nephrolithiasis, and weight loss.
Adverse effects of levetiracetam include agitation or aggressive behaviour, predominantly in younger children or elderly, and, rarely, psychosis or hallucinations. There are no significant drug interactions. It is renally cleared.
Safety of anticonvulsants in pregnancy must be taken into account when choosing a suitable drug. Topiramate may increase the risk of child neurodevelopmental disorders and has been associated with cleft lip and being small for gestational age.[52]Pack AM, Oskoui M, Williams Roberson S, et al. Teratogenesis, perinatal, and neurodevelopmental outcomes after in utero exposure to antiseizure medication: practice guideline from the AAN, AES, and SMFM. Neurology. 2024 Jun;102(11):e209279. https://www.neurology.org/doi/10.1212/WNL.0000000000209279?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed http://www.ncbi.nlm.nih.gov/pubmed/38748979?tool=bestpractice.com [68]Bjørk MH, Zoega H, Leinonen MK, et al. Association of prenatal exposure to antiseizure medication with risk of autism and intellectual disability. JAMA Neurol. 2022 Jul 1;79(7):672-81. https://jamanetwork.com/journals/jamaneurology/fullarticle/2793003 http://www.ncbi.nlm.nih.gov/pubmed/35639399?tool=bestpractice.com Zonisamide has been associated with an increased risk of fetal growth restriction.[71]Medicines and Healthcare products Regulatory Agency. Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review. Apr 2022 [internet publication]. https://www.gov.uk/drug-safety-update/antiepileptic-drugs-in-pregnancy-updated-advice-following-comprehensive-safety-review Levetiracetam has not been associated with an increased risk of major congenital malformations or an increased risk of neurodevelopmental disorders or delay. However, antenatal exposure to levetiracetam may be associated with an increased risk of ADHD.[72]Dreier JW, Bjørk MH, Alvestad S, et al. Prenatal exposure to antiseizure medication and incidence of childhood- and adolescence-onset psychiatric disorders. JAMA Neurol. 2023 Jun 1;80(6):568-77. https://jamanetwork.com/journals/jamaneurology/fullarticle/2803245 http://www.ncbi.nlm.nih.gov/pubmed/37067807?tool=bestpractice.com A specialist should be consulted for more guidance on the use of specific drugs in pregnancy.
Primary options
topiramate: children 2-16 years of age: 1-3 mg/kg/day orally once daily at night for 1 week initially, increase by 1-3 mg/kg/day increments given in 2 divided doses every 1-2 weeks according to response, maximum 15 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
OR
zonisamide: children <16 years of age: 1-2 mg/kg/day orally given in 2 divided doses initially, increase by 0.5 to 1 mg/kg/day increments every 2 weeks according to response, maximum 8 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
OR
levetiracetam: children 4-16 years of age: 10 mg/kg/dose orally twice daily initially, increase by 10 mg/kg/dose increments every 2 weeks, maximum 60 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
ketogenic diet
Treatment recommended for ALL patients in selected patient group
In the subgroup of patients with GLUT1 deficiency, a ketogenic diet is recommended. Patients are monitored and treated by an epileptologist.
This is typically a high-fat, adequate-protein, low-carbohydrate diet, and should be initiated in hospital, under close medical supervision. It may take a couple of months before a clinical response is noted.
Anticonvulsant therapy is continued initially. If a patient responds very well and has little or no seizure activity, drug treatment is tapered slowly.
typical absence seizures with a history of generalised tonic-clonic seizures (CAE, JAE, JME)
valproic acid or lamotrigine
If there is any history of generalised tonic-clonic seizures (childhood absence epilepsy [CAE], juvenile absence epilepsy [JAE], and juvenile myoclonic epilepsy [JME]), ethosuximide is less appropriate, and valproic acid and lamotrigine would be preferred first-line agents.[41]Brigo F, Igwe SC, Lattanzi S. Ethosuximide, sodium valproate or lamotrigine for absence seizures in children and adolescents. Cochrane Database Syst Rev. 2019 Feb 8;2:CD003032.
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD003032.pub4/full
http://www.ncbi.nlm.nih.gov/pubmed/30734919?tool=bestpractice.com
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What are the comparative effects of ethosuximide, sodium valproate, or lamotrigine for children and adolescents with absence seizures?/cca.html?targetUrl=https://www.cochranelibrary.com/cca/doi/10.1002/cca.2582/fullShow me the answer
Valproic acid can cause hepatotoxicity and pancreatitis, thrombo/pancytopenia, hyperammonaemia, fatigue, weight gain, and hair thinning. Periodic monitoring of FBCs and liver transaminases should be strongly considered. Trough drug levels can help with assessing compliance and effectiveness of therapy.
Valproic acid should be used with extreme caution in children aged younger than 2 years, due to increased risk of hepatotoxicity in this age group.
When initiating lamotrigine treatment, a slow titration is necessary to avoid the serious complication of Stevens-Johnson syndrome. Rare cases of hepatotoxicity or multi-organ failure have been reported. Adverse effects also include diplopia, ataxia, and insomnia.
Safety of anticonvulsants in pregnancy must be taken into account when choosing a suitable drug. Valproic acid and its derivatives may cause major congenital malformations, including neurodevelopmental disorders and neural tube defects, after in utero exposure.[52]Pack AM, Oskoui M, Williams Roberson S, et al. Teratogenesis, perinatal, and neurodevelopmental outcomes after in utero exposure to antiseizure medication: practice guideline from the AAN, AES, and SMFM. Neurology. 2024 Jun;102(11):e209279. https://www.neurology.org/doi/10.1212/WNL.0000000000209279?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed http://www.ncbi.nlm.nih.gov/pubmed/38748979?tool=bestpractice.com These drugs are contraindicated during pregnancy; however, if it is not possible to stop them, treatment may be continued with appropriate specialist care. Valproic acid and its derivatives must only be used in female patients of childbearing potential if certain precautionary measures are in place (e.g., only used if no suitable alternatives, a pregnancy prevention programme is in place); consult your local guidance for more information. Lamotrigine has not been associated with an increased risk of major congenital malformations or an increased risk of neurodevelopmental disorders or delay.[72]Dreier JW, Bjørk MH, Alvestad S, et al. Prenatal exposure to antiseizure medication and incidence of childhood- and adolescence-onset psychiatric disorders. JAMA Neurol. 2023 Jun 1;80(6):568-77. https://jamanetwork.com/journals/jamaneurology/fullarticle/2803245 http://www.ncbi.nlm.nih.gov/pubmed/37067807?tool=bestpractice.com A specialist should be consulted for more guidance on the use of specific drugs in pregnancy.
Primary options
valproic acid: children <10 years of age: consult specialist for guidance on dose; adults and children ≥10 years of age: 15 mg/kg/day orally given in 1-3 divided doses initially, increase by 5-10 mg/kg/day increments every 7 days as tolerated and according to response
OR
lamotrigine: children and adults: consult specialist for guidance on dose
topiramate or zonisamide or levetiracetam
Additional treatment recommended for SOME patients in selected patient group
Second-line agents that are added as adjunct therapy to first-line therapy. Consideration may be given to weaning the first-line agent when seizures are under control.
Adverse effects of topiramate include word-finding difficulties or cognitive problems, weight loss, nephrolithiasis, and anhidrosis. Rarely, it can precipitate acute angle-closure glaucoma. Therefore, eye pain should be treated as an emergency.
Adverse effects of zonisamide include cognitive slowing, abdominal pain, nephrolithiasis, and weight loss.
Adverse effects of levetiracetam include agitation or aggressive behaviour, predominantly in younger children or elderly, and, rarely, psychosis or hallucinations. There are no significant drug interactions. It is renally cleared.
Safety of anticonvulsants in pregnancy must be taken into account when choosing a suitable drug. Topiramate may increase the risk of child neurodevelopmental disorders and has been associated with cleft lip and being small for gestational age.[52]Pack AM, Oskoui M, Williams Roberson S, et al. Teratogenesis, perinatal, and neurodevelopmental outcomes after in utero exposure to antiseizure medication: practice guideline from the AAN, AES, and SMFM. Neurology. 2024 Jun;102(11):e209279. https://www.neurology.org/doi/10.1212/WNL.0000000000209279?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed http://www.ncbi.nlm.nih.gov/pubmed/38748979?tool=bestpractice.com [68]Bjørk MH, Zoega H, Leinonen MK, et al. Association of prenatal exposure to antiseizure medication with risk of autism and intellectual disability. JAMA Neurol. 2022 Jul 1;79(7):672-81. https://jamanetwork.com/journals/jamaneurology/fullarticle/2793003 http://www.ncbi.nlm.nih.gov/pubmed/35639399?tool=bestpractice.com Zonisamide has been associated with an increased risk of fetal growth restriction.[71]Medicines and Healthcare products Regulatory Agency. Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review. Apr 2022 [internet publication]. https://www.gov.uk/drug-safety-update/antiepileptic-drugs-in-pregnancy-updated-advice-following-comprehensive-safety-review Levetiracetam has not been associated with an increased risk of major congenital malformations or an increased risk of neurodevelopmental disorders or delay. However, antenatal exposure to levetiracetam may be associated with an increased risk of ADHD.[72]Dreier JW, Bjørk MH, Alvestad S, et al. Prenatal exposure to antiseizure medication and incidence of childhood- and adolescence-onset psychiatric disorders. JAMA Neurol. 2023 Jun 1;80(6):568-77. https://jamanetwork.com/journals/jamaneurology/fullarticle/2803245 http://www.ncbi.nlm.nih.gov/pubmed/37067807?tool=bestpractice.com A specialist should be consulted for more guidance on the use of specific drugs in pregnancy.
Primary options
topiramate: children 2-16 years of age: 1-3 mg/kg/day orally once daily at night for 1 week initially, increase by 1-3 mg/kg/day increments given in 2 divided doses every 1-2 weeks according to response, maximum 15 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
OR
levetiracetam: children 4-16 years of age: 10 mg/kg/dose orally twice daily initially, increase by 10 mg/kg/dose increments every 2 weeks, maximum 60 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
OR
zonisamide: children <16 years of age: 1-2 mg/kg/day orally given in 2 divided doses initially, increase by 0.5 to 1 mg/kg/day increments every 2 weeks according to response, maximum 8 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
atypical absence seizures
valproic acid or lamotrigine or topiramate
Valproic acid, lamotrigine, and topiramate are all indicated for first-line treatment of atypical absence seizures, syndromes with generalised epilepsies, or multiple seizure types.
Valproic acid can cause hepatotoxicity and pancreatitis, thrombo/pancytopenia, hyperammonaemia, fatigue, weight gain, and hair thinning. Periodic monitoring of FBCs and liver transaminases should be strongly considered. Trough drug levels can help with assessing compliance and effectiveness of therapy.
Valproic acid should be used with extreme caution in children aged less than 2 years, due to increased risk of hepatotoxicity in this age group.
When initiating lamotrigine treatment, a slow titration is necessary to avoid the serious complication of Stevens-Johnson syndrome. Rare cases of hepatotoxicity or multi-organ failure have been reported. Adverse effects also include diplopia, ataxia, and insomnia.
Adverse effects of topiramate include word-finding difficulties or cognitive problems, nephrolithiasis, and anhidrosis. Rarely, it can precipitate acute angle-closure glaucoma. Therefore, eye pain should be treated as an emergency.
Safety of anticonvulsants in pregnancy must be taken into account when choosing a suitable drug. Valproic acid and its derivatives may cause major congenital malformations, including neurodevelopmental disorders and neural tube defects, after in utero exposure.[52]Pack AM, Oskoui M, Williams Roberson S, et al. Teratogenesis, perinatal, and neurodevelopmental outcomes after in utero exposure to antiseizure medication: practice guideline from the AAN, AES, and SMFM. Neurology. 2024 Jun;102(11):e209279. https://www.neurology.org/doi/10.1212/WNL.0000000000209279?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed http://www.ncbi.nlm.nih.gov/pubmed/38748979?tool=bestpractice.com These drugs are contraindicated during pregnancy; however, if it is not possible to stop them, treatment may be continued with appropriate specialist care. Valproic acid and its derivatives must only be used in female patients of childbearing potential if certain precautionary measures are in place (e.g., only used if no suitable alternatives, a pregnancy prevention programme is in place); consult your local guidance for more information. Lamotrigine has not been associated with an increased risk of major congenital malformations or an increased risk of neurodevelopmental disorders or delay.[71]Medicines and Healthcare products Regulatory Agency. Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review. Apr 2022 [internet publication]. https://www.gov.uk/drug-safety-update/antiepileptic-drugs-in-pregnancy-updated-advice-following-comprehensive-safety-review Topiramate may increase the risk of child neurodevelopmental disorders and has been associated with cleft lip and being small for gestational age.[52]Pack AM, Oskoui M, Williams Roberson S, et al. Teratogenesis, perinatal, and neurodevelopmental outcomes after in utero exposure to antiseizure medication: practice guideline from the AAN, AES, and SMFM. Neurology. 2024 Jun;102(11):e209279. https://www.neurology.org/doi/10.1212/WNL.0000000000209279?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed http://www.ncbi.nlm.nih.gov/pubmed/38748979?tool=bestpractice.com [68]Bjørk MH, Zoega H, Leinonen MK, et al. Association of prenatal exposure to antiseizure medication with risk of autism and intellectual disability. JAMA Neurol. 2022 Jul 1;79(7):672-81. https://jamanetwork.com/journals/jamaneurology/fullarticle/2793003 http://www.ncbi.nlm.nih.gov/pubmed/35639399?tool=bestpractice.com A specialist should be consulted for more guidance on the use of specific drugs in pregnancy.
Primary options
valproic acid: children <10 years of age: consult specialist for guidance on dose; adults and children ≥10 years of age: 15 mg/kg/day orally given in 1-3 divided doses initially, increase by 5-10 mg/kg/day increments every 7 days as tolerated and according to response
OR
lamotrigine: children and adults: consult specialist for guidance on dose
OR
topiramate: children 2-16 years of age: 1-3 mg/kg/day orally once daily at night for 1 week initially, increase by 1-3 mg/kg/day increments given in 2 divided doses every 1-2 weeks according to response, maximum 15 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
levetiracetam or zonisamide
Additional treatment recommended for SOME patients in selected patient group
Typically, zonisamide and levetiracetam are second-line agents that are added as adjunct therapy to first-line therapy. Consideration may be given to weaning the first-line agent when seizures are under control.
Adverse effects of levetiracetam include agitation or aggressive behaviour, predominantly in younger children or elderly, and, rarely, psychosis or hallucinations. There are no significant drug interactions. It is renally cleared.
Adverse effects of zonisamide include cognitive slowing, abdominal pain, nephrolithiasis, and weight loss.
Safety of anticonvulsants in pregnancy must be taken into account when choosing a suitable drug. Levetiracetam has not been associated with an increased risk of major congenital malformations or an increased risk of neurodevelopmental disorders or delay. However, antenatal exposure to levetiracetam may be associated with an increased risk of ADHD.[72]Dreier JW, Bjørk MH, Alvestad S, et al. Prenatal exposure to antiseizure medication and incidence of childhood- and adolescence-onset psychiatric disorders. JAMA Neurol. 2023 Jun 1;80(6):568-77. https://jamanetwork.com/journals/jamaneurology/fullarticle/2803245 http://www.ncbi.nlm.nih.gov/pubmed/37067807?tool=bestpractice.com Zonisamide has been associated with an increased risk of fetal growth restriction.[71]Medicines and Healthcare products Regulatory Agency. Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review. Apr 2022 [internet publication]. https://www.gov.uk/drug-safety-update/antiepileptic-drugs-in-pregnancy-updated-advice-following-comprehensive-safety-review A specialist should be consulted for more guidance on the use of specific drugs in pregnancy.
Primary options
levetiracetam: children 4-16 years of age: 10 mg/kg/dose orally twice daily initially, increase by 10 mg/kg/dose increments every 2 weeks, maximum 60 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
OR
zonisamide: children <16 years of age: 1-2 mg/kg/day orally given in 2 divided doses initially, increase by 0.5 to 1 mg/kg/day increments every 2 weeks according to response, maximum 8 mg/kg/day; adolescents and adults: refer to consultant for guidance on dosage
refractory to treatment
specialist referral
Multiple other therapies can be considered if first and second lines have failed (i.e., lack of seizure freedom), such as acetazolamide, felbamate, the ketogenic diet, and vagal nerve stimulation. These are beyond the scope of this review and would be initiated by an epileptologist.
GLUT1 testing should be considered before initiating the ketogenic diet.
Drugs usually more appropriate for focal seizures, such as carbamazepine and phenytoin, are generally felt to worsen generalised seizures, including absence seizures.
Choose a patient group to see our recommendations
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer
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