Which of these cold meds are the most effective, tussionex or hycodan (hydrocodone)?

Depends: Neither is particularly effective. Recent tudies of cough medications have shown that codeine-containing cough medications work about as well as sugar pills (placebo) and other studies show hydrocodone equal to Codeine . Theoretically Hycodan (with an anticholinergic) should work better for productive coughs and tussionex (with an antihistamine) should work better if there's an allergy component.