I did a post about the effervescent codeine products not long ago. Pasting it here:

The "alka seltzer" style codine containing products that I have used are:

Paracodol/Co-codamol (SAME THING) got this OTC in England) (only 8mgs codeine per effervescent tablet--they are about an inch in diameter and are scored--also contains APAP)

Generic Effervescent Codeine with APAP--in lieu of Tylenol 3's (30mgs per tablet, same size tab--looks just like an Alka Seltzer--and has 500mgs APAP, I think)

Dafalgan Eff. Codeine (got this in France) has 30mgs codeine and 500 APAP...same tablet style...

Efferalgan (also from France) 30mgs codeine/600 APAP

These are the only ones I have used or know of.

Hope that helps!