it works for me, but not like i get any higher, i just don't really increase my doses. i've actually lowered the amount i need to take to "feel" benzos, amps, and opiates with time + NMDA-antagonists, but by time i am talking by months, and NOT mere days or even weeks...
memantine is ideal, but low doses of DXM (30-90mgs) will provide decent results..don't expect anything magical or mind-bl0wing though....