Primidone Valproate

Carbamazepine is a hepatic microsomal enzyme inducer and therefore will lower the serum concentration of a wide variety of drugs given concurrently. These include the antiepileptic drugs phenytoin, primidone, valproate, ethosuximide and clonazepam. In addition, carbamazepine can compromise the therapeutic effects of oral contraceptives, oral anticoagulants, beta-blockers, haloperidol and theophylline. 

Clobazam Carbamazepine Primidone Valproate Phenytoin Interaction inconsistent, usually of little clinical significance Inhibition of metabolism of the object drug... 

Isonlazid Carbamazepine Diazepam Ethosuximide Phenobarbital Phenytoin Primidone Valproate High risk of toxicity, especially with carbamazepine and phenytoin Inhibition of metabolism of the object drugs... 

Tonic-clonic seizure As described above for partial with secondarily generalized tonic-clonic seizures except that it is not preceded by a partial seizure. Carbamazepine, phenobarbital, phenytoin, primidone, valproate Lamotrigine, topiramate... 

Epilepsy, monotherapy Indicated for conversion to monotherapy in adults with partial seizures who are receiving treatment with carbamazepine, phenytoin, phenobarbital, primidone, or valproate as the single antiepileptic drug (AED). 

Discontinuing carbamazepine, phenytoin, phenobarbital, or primidone should prolong the half-life of lamotrigine discontinuing valproate should shorten the half-life of lamotrigine. 

Drugs that may affect tiagabine include carbamazepine, phenobarbital, phenytoin, primidone, and valproate. Valproate may be affected by tiagabine. 

Drugs acting on GABA/glutamate - hypnotics/anxiolytics barbiturates, benzodiazepines, chlormethiazole, chloral derivatives, baclofen - anticonvulsants phenobarbitone, primidone, phe-nytoin, sodium, valproate, carbamazepine - alcohol, phencyclidine, ketamine... 

Lamotrigine is metabolized by glucuronidation, possibly by the UGT 1A4 system. As such, it is vulnerable to other UGT inducers—oral contraceptives, phenytoin, carbamazepine, phenobarbital and primidone, and to a UGT inhibitor, valproate (Hachad et ah, 2002). 

Herranz, J.L., Armijo, J.A., and Arteaga, R. (1988) Clinical side effects of phenobarbital, primidone, phenytoin, carbamazepine, and valproate during monotherapy in children. Epilepsia 29 794-804. 

Approximately doubles widi valproate and decreases by approximately half with carbamazepine/primidone/phenytoin/phenobar-bital/rifampin therefore, initial doses may vary depending on concomitant medications. 

Valproate metabolism may be induced by other anticonvulsants, including carbamazepine, phenytoin, primidone, and phenobarbital, resulting in an increased total clearance of valproate and perhaps decreased efficacy. 

For simple and complex partial seizures and secondary generalized tonic-clonic seizures, the first line drugs are - carbamazepine, valproate and phenytoin. Second line drugs include - acetazolamide, clobazam, clonazepam, ethosuximide, felbamate, gabapentin, lamotrigine, levetiracetam, oxacarbamazepine, primidone, tiagabine, topiramate and vigabactin. 

For generalized absence seizures, first line treatment is with valproate or ethosuximide and second line treatment with acetazolamide, clobazam, clonazepam, lamotrigine, phenobarbitone and primidone. 

Myoclonic seizures are best treated with valproate but, as a second choice, with clobazam, clonazepam, ethosuximide, lamotrigine, phenobarbitone, piracetam or primidone. 

Valproate, phenobarbitone, carbamazepine, diphenylhydantoin Valproate, ethosuximide, primidone... 

VALPROATE 1. BARBITURATES -phenobarbital, primidone 2. 7ETHOSUXIMIDE 3. LAMOTRIGINE t levels of these antiepileptics Uncertain Watch for early features of toxicity. Measure levels where possible... 

Antiepilepsy. General note of caution observe the infant for sedation and poor suckling. Primidone, ethosuximide and phenobarbital are present in milk in high amounts phenytoin and sodium valproate less so. 

Sodium valproate appears to be a nonspecific inhibitor and impairs the metabolism of phenytoin, phenobarbitone and primidone. 

Antiepilepsy drugs pass into breast milk (see p. 116), phenobarbital, primidone and ethosuximide in significant quantities, phenytoin and sodium valproate less so. There is a risk that the baby will become sedated or suckle poorly but, provided a watch is maintained for these effects, the balance of advantage favours breast feeding whilst taking antiepilepsy drugs. 

Anticonvulsants. Carbamazepine, phenobarbital and primidone accelerate warfarin metabolism (enzyme induction) the effect of phenytoin is variable. Clonazepam and sodium valproate are safe. 

Phenobarbital Phenytoin Primidone Felbamate Lamotrigine Tiagabide Topiramate Valproate Zonisamide Clobazam Clonazepam Diazepam usually compensated by the effect of the added drug risk of toxicity when interfering drug is discontinued drug... 

Valproate Carbamazepine epoxide Diazepam Felbamate Lamotrigine Phenobarbital Risk of toxicity, particularly with phenobarbital including primidone-derived phenobarbital and lamotrigine Inhibition of metabolism of the affected drug. Valproate also displaces diazepam from protein binding sites, affecting relation between total diazepam concentration and effect... 

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