Lamotrigine Phenobarbital

Drugs that may affect valproic acid include carbamazepine, charcoal, chlorpromazine, cholestyramine, cimetidine, erythromycin, ethosuximide, felbamate, lamotrigine, phenytoin, rifampin, and salicylates. Drugs that may be affected by valproic acid include carbamazepine, clonazepam, diazepam, ethosuximide, lamotrigine, phenobarbital, phenytoin, tolbutamide, tricyclic antidepressants, warfarin, and zidovudine. 

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... 

Activated charcoal Carbamazepine Lamotrigine Phenobarbital Phenytoin Valproate With some drugs can be exploited to reduce drug concentrations in overdose Sequestration in the gastrointestinal tract... 

Clinically important, potentially hazardous interactions with carbamazepine, lamotrigine, phenobarbital, phenytoin, pregabalin... 

Decreased effects with rifampin, carbamazepine, cholestyramine, phenytoin, lamotrigine, phenobarbital... 

Importantly, Loscher et al. found that carbamazepine, felbamate, gabapentin, lamotrigine, phenobarbital, and topiramate are substrates of ABCBl (P-gp) [38]. Crowe et al. also studied the transport of a variety of antiepileptic drugs including vigabatrin, gabapentin, phenobarbitone, lamotrigine, phenytoin, carbamazepine, and acetazolamide in colorectal tumor-derived Caco-2 cell monolayers. They found that only one antiepileptic, acetazolamide, is a weak ABCBl substrate [39]. 

Furthermore, evidence from clinical studies suggests that levetiraeetam does not affect the serum levels of gabapentin, lamotrigine, phenobarbital, or primidone. In general therefore, no dosage adjustments would seem to be needed if levetiraeetam is used as add-on therapy with any of these drugs. 

There appears to be no pharmacokinetic interaction between pregabalin and carbamazepine, gabapentin, lamotrigine, phenobarbital, phenytoin, topiramate, valproate, alcohol, lorazepam, or oxycodone. However, the impairment of cognitive and gross motor function caused by oxycodone was additive with pregabalin, and pregabalin may potentiate the effects of alcohol and lorazepam. 

Phenobarbital, phenytoin and carbamazepine can cause a small to moderate reduction in the serum levels of zonisamide, while lamotrigine may increase zonisamide levels. Clonazepam and valproate have little or no effect. Zonisamide shows variable effects (a modest decrease, an increase, or no effect) on carbamazepine serum levels, but has no important effect on lamotrigine, phenobarbital, primidone or valproate levels. Most studies also suggest that zonisamide has no effect on phenytoin levels, but two showed a modest increase. 

Carbamazepine, phenytoin, phenobarbital, valproate, gabapentin, lamotrigine, levetiracetam, tiagabine, topiramate, zonisamide... 

Topiramate Lamotrigine Oxcarbazepine Phenobarbital Phenytoin Valproic acid... 

U.S. Expert Panel 2005 Valproic acid Carbamazepine Lamotrigine Oxcarbazepine Phenobarbital Phenytoin Topiramate Valproic acid Children Carbamazepine Phenobarbital Phenytoin Topiramate Valproic acid Lamotrigine... 

Valproic acid is an enzyme inhibitor that increases serum concentrations of concurrently administered phenobarbital and may increase concentrations of carbamazepine 10,11-epoxide without affecting concentrations of the parent drug. It also inhibits the metabolism of lamotrigine. 

The apparent clearance of lamotrigine is affected by the coadministration of AEDs. Lamotrigine is eliminated more rapidly in patients who have been taking hepatic enzyme inducing antiepileptic drugs (ElAEDs), including carbamazepine, phenytoin, phenobarbital, and primidone. 

Lamotrigine Added to Carbamazepine, Phenytoin, Phenobarbital, or Primidone (Without Valproic Acid) in Patients >12 Years of Age ... 

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

Stopping oral contraceptives - For women not taking carbamazepine, phenytoin, phenobarbital, primidone, or rifampin, the maintenance dose of lamotrigine may need to be decreased by as much as 50% of the maintenance dose with concurrent oral contraceptives. 

Drugs that may affect lamotrigine include acetaminophen, carbamazepine, folate inhibitors, oral contraceptives, phenobarbital, phenytoin, primidone, rifamycins, succinimides, and valproic acid. 

Drugs that can decrease carbamazepine serum levels include charcoal, cisplatin, doxorubicin, felbamate, hydantoins, rifampin, phenobarbital, primidone, theophylline. The serum levels of oral contraceptives, haloperidol, bupropion, anticoagulants, felbamate, valproic acid, felodipine, tricyclic antidepressants, acetaminophen, ziprasidone, voriconazole, topiramate, tiagabine, olanzapine, and lamotrigine can be lowered by carbamazepine. 

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). 

Valproate may increase concentrations of phenobarbital, etho-suximide, and the active 10,11-epoxide metabolite of carba-mazepine, increasing the risk of toxicity. Valproate may also raise lamotrigine levels, increasing the risk of rash. 

Phenobarbital Enhances phasic GABAa receptor responses reduces excitatory synaptic responses Nearly complete absorption not significantly bound to plasma proteins peak concentrations in Vi to 4 h no active metabolites tjy2 varies from 75 to 125 h Generalized tonic-clonic seizures, partial seizures, myoclonic seizures, generalized seizures, neonatal seizures, status epilepticus Toxicity Sedation, cognitive issues, ataxia, hyperactivity Interactions Valproate, carbamazepine, felbamate, phenytoin, cyclosporine, felodipine, lamotrigine, nifedipine, nimodipine, steroids, theophylline, verapamil, others... 

Partial seizures Carbamazepine Phenytoin Lamotrigine Valproic acid Oxcarbazepine Gabapentin Topiramate Levetiracetam Zonisamide Tiagabine Primidone, phenobarbital Felbamate... 

Tonic-clonic Phenytoin, carbamazepine, valproic acid Lamotrigine, topiramate, phenobarbital, primidone, oxcarbazepine... 

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