Lamotrigine and Phenytoin interaction

Carbamazepine, phenytoin, phenobarbital, primidone, and rifampin decrease lamotrigine concentrations by approximately 40%.

Phenytoin ↓ lamotrigine Decreased lamotrigine concentration approximately 40%.

Patients with History of Allergy or Rash to Other Antiepileptic Drugs The risk of rash may be increased in patients with a history of allergy or rash to other AEDs.

Carbamazepine, felbamate, lamotrigine, topiramate, oxcarbazepine, lacosamide Antilipidemic agents Atorvastatin, fluvastatin, simvastatin Antiplatelets Ticagrelor Antiviral agents Efavirenz, lopinavir/ritonavir, indinavir, nelfinavir, ritonavir, saquinavir Fosamprenavir: phenytoin when given with fosamprenavir alone may decrease the concentration of amprenavir,…

Limited evidence suggests that HLA-B*1502 may be a risk factor for the development of SJS/TEN in patients of Asian ancestry taking other antiepileptic drugs associated with SJS/TEN, including phenytoin.

…defects), and abnormalities characteristic of fetal hydantoin syndrome, including dysmorphic skull and facial features, nail and digit hypoplasia, growth abnormalities (including microcephaly), and cognitive deficits, have been reported among children born to epileptic women who took phenytoin alone or in combination with other antiepileptic drugs during pregnancy.