| خلاصه مقاله | Drug interactions and rational polytherapy
Saeid Charsouei ,MD,Associate Professor of Neurology ,Epilepsy Fellowship,
Tabriz University of Medical Sciences
Rational polytherapy is defined as identify AEDs combinations that maximize efficacy and minimize side effects. When the first antiepileptic drug monotherapy fails, the second-line AED should be tried as an alternative monotherapy, while polytherapy should be considered only after the failure of at least two monotherapies.
The addition of a fourth drug should be generally avoided, considering that the use of more than three AEDs tends to deeply reduce the safety and tolerability, due to the occurrence of adverse events (AEs) and a scarce improvement in seizure control . Co-medication may increase the risk of idiosyncratic reactions : for example, valproate/lamotrigine combination augments the probability of lamotrigine-induced hypersensitivity.
Enzyme-inducing AEDs/valproate associations increase the risk of pancreatitis, hyperammonaemia , hepatotoxicity and encephalopathy
Postural and action tremor can be caused by either each drug or a summary effect of the combination of the valproate/lamotrigine.
Generally, recommended dosing regimens for lamotrigine when used in combination with valproate are halves doses. Phenobarbital, phenytoin and carbamazepine induce the metabolism of liposoluble drugs such as oral anticoagulants, antiretrovirals ,immunosuppressants , antiarrhythmics and oral contraceptives.
There are several chronic adverse effects caused by enzyme induction such as sexual dysfunction, reduced bone density, changes in cholesterol concentration and other cardiovascular effects.
Carbamazepine, lamotrigine, ethosuximide, phenytoin and phenobarbital should be avoided in patients with hematological disorders since they can cause bone marrow suppression.
Pregabalin, gabapentin, vigabatrin and valproate may lead to an increase in body weight and therefore, should be avoided in obese or diabetic subjects. |