Listen to me and listen to me hard.

ZICAM. 1 bottle contains .75 ounces of a watery liquid containing only DXM. 300mg of dex.

Stop popping 15 pills or chugging cough syrup. This hits harder and faster than all of these and it's easier to knock back. Enjoy.

EDIT: There is also a Z-Nite type that contains 540mg of dex. This is a very intense trip, however. Take caution...try a Zicam regular once or twice before you do this, imo.