• Clinical science

Anticonvulsant drugs


Anticonvulsant drugs are classified as either classic or newer anticonvulsants. Newer anticonvulsants are usually better tolerated and have a broader therapeutic range than classic anticonvulsant drugs. The choice of drug is guided by the type of seizure. First-line treatment for focal seizures includes e.g., lamotrigine or levetiracetam, while valproate is used for generalized seizures. All anticonvulsants have dose-dependent side effects on the central nervous system such as somnolence and nausea, but some agents have more specific side effects (e.g., gingival hyperplasia caused by phenytoin).

Besides their importance in anti-epileptic therapy, anticonvulsants are also used for pain management (e.g., carbamazepine or gabapentin as coanalgesics) or as mood stabilizers in bipolar disorders (valproate).


Agent Indication Mechanism of action Side effects

Classic anticonvulsants


  • Inhibits GABA transaminase GABA → decreased neuronal excitability
  • Inactivates Na+ channels


  • Inactives Na+ channels


  • Inhibition of voltage-gated calcium channels (T-type) in neurons of the thalamus


  • Inactivation of Na+ channels
  • Zero-order elimination (i.e., constant rate of drug eliminated)
Newer anticonvulsants


  • Exanthema, exfoliative dermatitis, Stevens-Johnson syndrome (slow dose increase necessary to prevent skin and mucous membrane reactions)
  • Rarely hepatotoxic or nephrotoxic
  • Blurry vision
  • Gastrointestinal symptoms
  • Sedation
  • Tolerance and dependence
  • Cardiorespiratory depression
  • Induces cytochrome P-450
  • Somnolence, nausea
  • Psychiatric symptoms (e.g., changes in personality)
  • Inhibition of voltage-gated calcium channels (T-type and L-type) in neurons of the thalamus
  • Inhibits GABA transaminaseGABA
  • Irreversible vision loss


  • Blocks voltage-gated Na+
  • GABA
  • Gastrointestinal upset: nausea, vomiting, diarrhea
  • Insomnia
  • Drowsiness
  • Weight changes



Anticonvulsant drugs inhibit neural activity (↓ neural excitation, ↑ neural inhibition) and increase the seizure threshold by interacting with specific receptors and ion channels.


Guidelines & therapy recommendations

  • Monotherapy should always be the first-line treatment → increase dosage before initiating combination therapy
  • Combination therapy: drugs from different classes and/or with different pharmacologic modes of action for refractory seizures
  • For more detailed approaches to seizure treatment and epilepsy, see treatment of epileptic seizures.


Special patient groups

Pregnancy and breastfeeding

  • Classic anticonvulsants (especially carbamazepine and sodium valproate!) should be avoided if possible → teratogenic effects
  • Newer anticonvulsants: lack of medical data and trials during pregnancy
  • Choice of treatment depends on type of seizure and which substance enables optimal control of treatment.
  • Approach
    • Optimize seizure control prior to conception.
    • Avoid multiple therapies.
    • Administer the drug at the lowest dose which controls seizures.
    • Monitor plasma drug levels regularly.


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  • 3. Schmidt D, Schachter SC. Drug treatment of epilepsy in adults. BMJ. 2014; 348(feb28 2): pp. g254–g254. doi: 10.1136/bmj.g254.
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last updated 03/18/2020
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