Memotin Drug Interactions

Drug Affecting Hepatic Microsomal Enzymes: Inhibitors or inducers of cytochrome P-450 (CYP) system; pharmacokinetic interactions unlikely.
Drug Metabolized by Hepatic Microsomal Enzymes: Minimal inhibition of CYP isoenzymes 1A2, 2A6, 2C9, 2D6, 2E1, or 3A4 by memantine observed in vitro. No induction of CYP isoenzymes 1A2, 2C9, 2E1, or 3A4/5 observed in vitro at concentrations exceeding those associated with therapeutic efficacy. Pharmacokinetic interaction unlikely.
Protein-bound Drugs: Because plasma protein binding of memantine is low (45%), a pharmacokinetic interaction with drugs that are highly protein bound (e.g., digoxin, warfarin) is unlikely.
Drug Secreted by Renal Tubular Cationic Transport: Potential pharmacokinetic interaction (altered plasma concentrations of both drugs) when memantine is used with drugs secreted by same renal cationic system (e.g., cimetidine, hydrochlorothiazide, metformin, nicotine, quinidine, ranitidine, triamterene). However, concomitant use of memantine with a fixed combination of hydrochlorothiazide and triamterene did not affect bioavailability of either memantine or triamterene, and maximum plasma concentrations and area under the plasma concentration-time curve (AUC) of hydrochlorothiazide decreased by only 20%. In addition, concomitant use of memantine with a fixed combination of glyburide and metformin hydrochloride did not affect the pharmacokinetics of memantine, metformin, or glyburide, and the hypoglycemic effect of the glyburide-metformin combination were not affected.
Alkalinizing Agents: Potential decreased memantine clearance with resulting increases in adverse effects when the drug is used concomitantly with agents that increase urine pH (e.g., carbonic anhydrase inhibitors, sodium bicarbonate). Use with caution. Memantine clearance was decreased by approximately 80% at alkaline urine conditions (i.e., pH 8).
Cholinesterase Inhibitors: Concomitant use of memantine with the acetylcholinesterase inhibitor donepezil did not affect the pharmacokinetics of either drug or substantially alter acetylcholinesterase inhibitor by donepezil. In a 24-week clinical study in patients with moderate to severe Alzheimer's disease, adverse effects observed with combination therapy with memantine and donepezil were similar to those observed with donepezil alone. In vitro and animal studies indicate that memantine does not affect the reversible inhibition of acetylcholinesterase produced by donepezil, galantamine, or tacrine.
N-Methyl-D-aspartate (NMDA) Antagonists: Concomitant use of memantine hydrochloride with other NMDA antagonist (e.g., amantadine, ketamine, dextromethorphan) has not been systematically evaluated. Use with caution.