Concentration-dependent mechanisms of adverse drug reactions in epilepsy

Antiepileptic drugs can cause some adverse effects ranging from mild to acute and serious ones. The inducing properties of some of them may result in vitamin D, vitamin K and estrogens catabolism and thus risk of fractures or efflux transport overexpression at the blood brain barrier and consequently lack of effect at the action site. Some are responsible for the formation of reactive metabolites, such as arene oxides or atropaldehyde intermediates, in skin, liver and other organs, causing hypersensitivity reactions or can enhance a commonly minor metabolic pathway increasing the formation of toxic metabolites. Drug-induced myopia and other visual problems have also been described with the use of antiepileptic agents. A pharmacological insight of the possible concentration-dependent mechanism involved in these reactions is given in this review and in some cases some preventive measures to revert them.