Yellow hydrocodone syrup, or brand name Tussionex, contains 10 milligrams of hydrocodone bitartrate per teaspoon, according to Drugs.com. Tussionex is a combination cough relief suspension, whereas straight hydrocodone syrup is red and contains 5 milligrams of hydrocodone bitartrate per teaspoon.
Drugs.com lists yellow food coloring as an inactive ingredient in Tussionex. Red, or cherry flavor, hydrocodone syrup contains caramel color and red food coloring. Both products are for cough relief, but their actual mechanisms remain unknown. Hydrocodone may be habit-forming. It is a narcotic produced from natural substances and acts like codeine. As an opium derivative, hydrocodone overdose can slow down or even stop breathing.