Having put the codeine extraction technique to good use over the last few months, i would like to tell you the pros and cons of australian OTC products.
Firstly, i wouldnt really advise using Panadeine in the extraction technique as paracetemol is generally much more soluble in colder water than both aspirin and ibuprofen, thus making more paracetemol left in the finished product. And understandably, no one really likes to cop a large dose of paracetemol with their codeine as even small doses are known to effect liver functioning.
Now on the ibuprofen front, its solubility levels are far less at colder tempretures so making less of it available in the filtered product. Considering that nurofen + has a fairly good dose of codeine in each tablet, using this product in the extraction technique is a good idea. Small doses of ibuprofen have no long lasting side effects, and generally are much better for you than paracetemol.
However, as apollo said, if you take ibuprofen on an empty stomach it can, and generally will, cause in the short term extreme nausuea, stomach cramps, and diaorrhea. If your gonna use Nurofen+ its very much advised to have something in your stomach before you take the finished product - but unfortunately, seeing as its best to take codeine on an empty stomach, this may reduce (only slightly) the effects of the codeine.
Now, from all that, i can assure you that if your living in Australia, the kind pharmaceutical folk have made a product with aspirin and codeine in it. Its called Veganin (8mg codeine, 350mg aspirin) and it comes in a red & white box and is usually kept in most pharmacies. Ive found this product the most effective in limiting unwanted substances in the filtered solution. Seeing as only a very very small amount of aspirin becomes soluble in a cool solution, then obviously your gonna get less nasties in the final product, and more good stuff. And even the small trace amounts of aspirin will not cause any short term or long term damage, unlike both ibuprofen & paracetemol. Thus you can take your codeine on an empty stomach, enjoy yourself, and not feel ill the next day.