Or any other brand or generic, pill or liquid. Robitussin and its copies are the same stuff plus water and sweetener. As long as you're getting guaifenesin and pseudoephedrine, it doesn't matter what brand, combined or separate, liquid or solid. Just read the label for the active ingredients.
When you get into the habit of reading OTC drug labels, you'll be amazed at how many of them are exactly the same. Even items from the same brand with different names, e.g. "<brand name> Sinus" and "<brand name> Cold and Flu" are likely to be absolutely identical.
Virtually all OTC cold medicines are some combination of:
- Acetaminophen or ibuprofen;
- Pseudoephedrine or phenylephrine*;
- Guaifenesin; and/or
* As Prfesser stated, if it's got phenylephrine you might as well put it back on the shelf. Products with pseudoephedrine are behind the counter but don't need a prescription. (They're restricted because it can be used as a precursor to make meth.)