Memxa 10 Drug Interactions

Due to the pharmacological effects and the mechanism of action of Memantine the following interactions may occur: The mode of action suggests that the effects of L-dopa, dopaminergic agonists, and anticholinergics may be enhanced by concomitant treatment with NMDA-antagonists such as Memantine. The effects of barbiturates and neuroleptics may be reduced. Concomitant administration of Memantine with the antispasmodic agents, Dantrolene or Baclofen, can modify their effects and a dose adjustment may be necessary.
Concomitant use of Memantine and Amantadine should be avoided, owing to the risk of pharmacotoxic psychosis. Both compounds are chemically related NMDA-antagonists. The same may be true for Ketamine and Dextromethorphan. There is one published case report on a possible risk also for the combination of Memantine and Phenytoin.
Other active substances such as Cimetidine, Ranitidine, Procainamide, Quinidine, Quinine and Nicotine that use the same renal cationic transport system as Amantadine may also possibly interact with Memantine leading to a potential risk of increased plasma levels.
There may be a possibility of reduced serum level of Hydrochlorothiazide (HCT) when Memantine is co-administered with HCT or any combination with HCT. Memantine did not inhibit CYP 1A2, 2A6, 2C9, 2D6, 2E1, 3A, flavin containing monooxygenase, epoxide hydrolase or sulphation in vitro.