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1. Antiepileptic drugs

2. Definition of epilepsy : It is a chronic disease characterized by repeated attacks of abnormal electrical discharge of cerebral neurons resulting in EEG ( electroencephalography ), motor, sensory, autonomic or psychological changes. Each attack is called a seizure or a fit. The group of unstable neurons which initiate the seizure is known as epileptic focus or seizure focus.

3. Causes of epilepsy : idiopathic, CNS infections, fever, metabolic defects and cerebral trauma.

4. Types of epilepsy: Partial (focal) Simple it involves a focal neurological symptoms that can be sensory (auditory and visual hallucination) or motor, consciousness is retained. Complex : the patient experienced loss of consciousness, confusion and sensory hallucination.

5. Generalized ( tonic-Clonic) or grand mal seizure: Tonic phase : loss of consciousness, rigidity, loss of bladder and bowel control. Clonic phase : jerking movements of the entire body. Status epilipticus : continuous seizure not separated by any period of regioned consciousness. It is medical emergency.

6. Absence (petit mal ) seizure : they usually occur in children (2-12 years ). They are characterized by a very brief few seconds loss of consciousness ( eye blinking or facial twitching). Febrile seizures : they occur in children because of fever ( last less than 10 min) Myoclonic convulsions : they occur at any age suddenly ( short periods of muscle contraction).

7. Classification of antiepileptic drugs They are classified according to their mechanism of action into:- Enhancement of GABA action ( phenobarbital, benzodiazepines , vigabartin). Inhibition of sodium channels ( phenytoin, carbamazepine, valproate, lamotrigine). Inhibition of calcium channels (ethosuximide).

8. Main use of these drugs is showed in table below. Type of epilepsy First choice Second choice Grand mal Phenytoin Carbamazepine, valproate, clonazepam, lamotrigine. Petit mal ( absence ) Ethosuximide Valproate, clonazepam Psychomotor Carbamazepine Phenytoin Status epilipticus Diazepam I.V Clonazepam I.V

9. Notes about antiepileptic drugs: Most antiepileptic drugs have low therapeutic indices, they have many side effects, and their level in the body should be monitored. These drugs have many drug –drug interactions because they are enzyme inducers except sodium valproate which is enzyme inhibitor. They decrease effect of many drugs such as oral contraceptive ( the dose of estrogen should be increased). Phenytoin has many side effect such as ( ataxia, vertigo, gum hypertrophy, hirsutirm, megaloblastic anemia, fetal malformation and hypersensitivity)

10. Antiepileptic drugs during pregnancy: Don’t stop therapy during pregnancy because fits may cause abortion . Antiepileptic drugs are teratogenic especially phenytoin and valproate ( cleft palate or lip and heart abnormalities) They decrease blood clotting of new born which could be treated by vitamin k. They pass to breast milk producing sedation to the baby.

11. Antipsychotic drugs Introduction : Schizophrenia is a particular type of psychosis that affects about 1 5 of the population. It is important form of psychiatric illness, because it affects young people, is often chronic and usually disabling.

12. Pathogenesis of schizophrenia : Genetic and environmental factors. Neurochemical theories : Dopamine hypothesis : the abnormality of dopamine physiology is completely responsible for the pathogenesis of schizophrenia. Glutamate theory : reduced glutamate concentrations and glutamate receptor tendencies have been reported in post-mortem brains of schizophrenics .

13. Serotonin theory : many effective antipsychotic drugs, in addition to blocking dopamine receptors, also act as 5HT receptor antagonists. These atypical drugs have fewer side effects associated with D2 receptor antagonist ( such as extrapyramidal effects).

14. Classification of antipsychotic drugs: Classical ( typical ) antipsychotics: chlorpromazine, haloperidol, thioridazine. Recent ( atypical) antipsychotic) : clozapine, Risperidone , Sulipride.

15. Mechanism of action : All psychotic drugs are antagonist at dopamine D2 receptor but most also block monoamine receptors, especially serotonin , alpha – receptors, H1 receptors and muscarinic receptors , so they have many side effects. Important side effects common to most drugs are motor disturbances ( Parkinson like symptoms, tardive dyskinesia, acute dystonia).

16. Advantages of atypical drugs over typical drugs: Less extrapyramidal side effect. Effective in treatment resistant group of patients Effective against negative symptoms.

17. The commonly used drugs and their side effects are summarized below in table . drug Side effect Chlorpromazine Increase prolactin (gynecomastia) Hypothermia, anticholinergic effect Hypersensitivity reactions , obstructive jaundice. Haloperidol As chlorpromazine, but does not cause jaundice. Clozapine Agranulocytosis, seizures, sedation, salivation, weight gain. Risperidone Weight gain , hypotension. Sulipride Increase prolactin.

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