In the red corner, we have Delsym (dextromethorphan) and in the blue corner, Robitussin-DM (guaifenesin and dextromethorphan). Ladies and Gentlemen, let's get ready to rumble! In the world of over-the-counter (OTC) cold medications, these two are undisputed champions, always on the frontlines when mucus and coughs declare war on our bodies. But do they fight the same battle? Or are they skilled in different styles of combat?

Both competitors carry dextromethorphan, a cough suppressant ninjutsu in their arsenal. However, Robitussin-DM (being the sneaky devil) also packs guaifenesin. Unlike the simple declaration of peace in the lung battlefield offered by dextromethorphan, guaifenesin wages war against the mucus invaders, thinning them down, and subsequently making the whole cough-it-up process a whole lot easier.

Now, let’s dive into our fighters in detail. Delsym, with its pure dextromethorphan content, suppresses the coughing reflex and goes for a direct punch. However, Delsym doesn't solve the underlying problem; instead, it offers you a temporary breather by reducing the urge to cough. So, if constant coughing is kicking your vocal cords where it hurts and sleep is as elusive as a diet you can stick to-Delsym might just be your guy.

But take note, fellow self-medicators! Even though Delsym is OTC, it can still tango with other drugs. So if you're currently teamed up with an MAOI drug, steer clear of Delsym. Your pharmacist is your trainer in this scenario; talk to them first.

Now, onto Robitussin-DM. As a two-in-one combo fighter, it not only suppresses coughs but also helps to evacuate the annoying mucus from your system. If your 'luges are throwing a phlegm party, Robitussin-DM is your bouncer.

Similarly, you must be wary of pairing up Robitussin-DM with MAOIs too. It's like whiskey and wine; both are great, but together they spell trouble.

In the end, both Delsym and Robitussin-DM are OTC warriors prepared to fight for you against common cold symptoms. But remember, your rivals – wet or dry coughs have different contenders - Delsym and Robitussin-DM respectively. Both these mighty medications come with their mild quirks and side-effects, but they are generally safe to use.

Just remember-a longstanding cough that's crashing your party for more than a week, accompanied by fever and headache party-poopers, requires a doctor’s supervision. And if you're on a medical cocktail already, check with your pharmacist if Delsym or Robitussin-DM can join the party or not. After all, everybody loves a good party, but no one loves a party foul.