Anti-Epileptic Drugs – This book covers the entire syllabus of “Pharmacology” prescribed by BNMC- for diploma in nursing science & midwifery students. We tried to accommodate the latest information and topics. This book is an examination setup according to the teachers’ lectures and examination questions.
At the end of the book, previous questions are given. We hope in touch with the book students’ knowledge will be upgraded and flourish. The unique way of presentation may make your reading of the book a pleasurable experience.
Anti-Epileptic Drugs
Epilepsy is a recurrent paroxysmal disorder of cerebral function, characterized by variable clouding of consciousness, often associated with localized or generalized convulsion.
Anti-epileptics are the agents that reduce of frequency of epileptic attacks. Seizures are divided into two groups: partial and generalized. Drugs used for partial seizures are more or less the same for all subtypes of partial seizures, but drugs used for generalized seizures are determined by the individual seizure subtype.
International Classification of seizure types
A. Partial seizures:
- Simple partial seizures
- Complex partial seizures
- Partial seizures secondarily generalized
B. Generalized seizures:
- Generalized tonic-clonic (grand-mal) seizures
- Absence (petit mal) seizures
- Tonic seizures
- Atonic seizures
- Clonic and myoclonic seizures
- Infantile spasm
Classification of Anti-epileptic drugs
A. According to Therapeutic utility
1. Major Seizures (Grand mal epilepsy):
- Ist choice: Phenytoin Crorism)
- 2nd choice: Carbamazepine, Phenobarbitone, Primidone, Na+ valproate, Clonazepam
2. Minor Seizures (Petit mal epilepsy):
- 1st choice: Na valproate, Ethosuximide
- 2nd choice: Clonazepam, Troxidone
3. Others: Methsuximide, Carbamazepine, Clonazepam, Phenytoin
B. According to Chemical nature
1. Barbiturate & related drugs: Phenobarbitone, Mephobarbitone
2. Hydantoins: Phenytoin, Mephenytoine, Ethotoine,
3. Oxazolidenediones: Trimethadione, Paramethadione
4. Succinimides: Phen-suximide, Meth-suximide, Etho-suximide
5. Benzodiazepines: Diazepam, Nitrazepam, Clobazam,
6. Acetyl urea derivatives: Acetazolamide
7. Newer drugs: Carbamazepine, Sodium valproate
Properties of main drugs
1. Safer and more effective
2. Non-sedative (or less)
Effective plasma levels of six anti-seizure drugs
| Drug | Effective level (mcg/ml) | High effective (mcg/ml) | Toxic level (mcg/ml) |
| Carbamazepine | 4-12 | 7 | >8 |
| primidone | 5-15 | 10 | <12 |
| phenytoin | 10-20 | 18 | >20 |
| phenobarbital | 10-40 | 35 | >40 |
| Ethosuximide | 50-100 | 80 | >100 |
| valproate | 50-100 | 80 | >100 |
Mechanism of action of anti-epileptic drugs
Current anti-epileptic (anti-convulsant) drugs are thought to be act mainly by:
1. Reducing electrical excitability of cell membranes, possibly through use-dependent block of sodium channels.
2. Enhancing GABA-mediated synaptic inhibition. This may be achieved by:
- Enhanced postsynaptic action of GABA by inhibiting GABA-transaminase.
- Drugs with direct GABA agonist properties; so increase GABA effects.
Adverse effects anti-epileptic drugs:
- Sedation,
- Fatigue,
- Dizziness,
- Coordination disturbances (ataxia, dysarthria, diplopia)
- Tremor
- Cognitive deficits,
- Mood alterations,
- Behavioural changes and
- Sexual disorders (loss of libido, erectile dysfunction).
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