This is what I found about Coricidin:

Coricidin is NOT a safe source of DXM for tripping. In addition to the 30 mg of dextromethorphan contained in Coricidin HBP Cough & Cold per pill, they also contain 4 mg of chlorpheniramine maleate. This is an anticholinergic drug, a class of drug which in general is very dangerous to take in large doses with dextromethorphan. Worse yet, chlorpheniramine maleate is also metabolized by the same liver enzyme (known as CYP-2D6) as is DXM. The competition for this limited enzyme by the two drugs makes taking them together, in large doses, a dangerous combination.

I found that here:
http://www.coricidin.org/

This:

Never take more of this medication than is directed. The maximum amount of acetaminophen for adults is 1 gram (1000 mg) per dose and 4 grams (4000 mg) per day. Taking more acetaminophen could cause damage to your liver. If you drink more than three alcoholic beverages per day, talk to your doctor before taking Coricidin and never take more than 2 grams (2000 mg) per day.
Symptoms of an Coricidin overdose may include nausea, vomiting, diarrhea, abdominal pain, sweating, seizure, confusion, sedation, insomnia, tremor, hallucinations, and an irregular heartbeat.

not take Coricidin if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A very serious drug interaction could occur, leading to serious side effects.

Found here:
http://www.drugs.com/coricidin.html

This:

There have been several cases of severe problems resulting from even moderate Coricidin use, including bleeding eyeballs (I'm not kidding), serious nausea, coma, and two confirmed deaths. DO NOT use Coricidin recreationally.

I've heard from about two dozen people who have had *serious* problems with Coricidin (and countless who have been turned off of it after regular use by nausea reactions when looking at the box in the drugstore; some people even projectile vomit upon seeing it).

Several people ended up bleeding out their eyeballs (I kid you not). About ten ended up in the hospital. One kid was in a coma for three days after *five* tablets. All of these people had taken ten or fewer.

Some people are *very* susceptible to antihistamines, and it can hit you suddenly, and randomly. It is seriously dangerous shit.

Found here:
http://www.third-plateau.org/dangers/coricidin.shtml

Why bother? Is all this damage worth being light headed for a few hours? Think about it.