Lamotrigine interaction with other drugs

Drug Interactions. Lamotrigine does not inhibit or induce liver enzymes and has a low potential for pharmacokinetic interactions with other drugs. Lamotrigine does not interfere with oral contraceptives. 

Use alone or in combina tion with other drugs (e.g, lithiunry catbatnaz-epin antipsychoti(3) for the acute treatment of mania and for rtrainte-nance trealmenl Use caution when combining with lamotrigine because ot potential drug interaction. 

Pharmacodynamic interactions also occur. In particular, the adverse effects of any drug can be increased by other drugs with similar properties. One example is the reciprocal potentiation of the neurotoxic effects of carbamazepine and lamotrigine in patients taking a combination of these drugs (180). Some drugs (for example ciclosporin, clozapine) have a proconvulsant effect and can reduce the efficacy of antiepileptic drugs. 

The most common adverse effects of lamotrigine include dizziness, weakness, headache, diplopia, ataxia, blurred vision, and somnolence (SEDA-18, 65) (SEDA-20, 63) (19). These effects resemble those seen with carbamaze-pine and can result from an adverse pharmacodynamic interaction. Tolerability is better when lamotrigine is given as monotherapy or with drugs other than carbama-zepine however, tremor develops in some patients taking valproate in combinations (SEDA-18, 66). During monotherapy, serum lamotrigine concentrations associated with intolerable adverse effects (mostly headache, dizziness, and ataxia) were 0.4-18.5 qg/ml and overlapped widely with those tolerated in other patients (20). 

Eriksson A-S, Hoppu K, Nerg rdh A, Boreus L, Pharmacokinetic interactions between lamotrigine and other antiepileptic drugs in children with intractable epilepsy. Epilepsia (1996) 37, 769-73,... 

None of the interactions between the benzodiazepines and antiepileptics described here appear to be of major clinical importance, with the possible exception of the interaction between clobazam and felbamate. If both drugs are given be aware that additive sedative or other adverse effects may occur. This may also be possible in some rare cases with chlordiazepoxide or clobazam and phenobarbital clonazepam and lamotrigine or primidone and clorazepate and primidone. 

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