I'm not sure if Head-On is an NSAID, but I've used a few topical NSAID's in the past and they've caused slightly irritation. But I've definately read somewhere that consuming the recommended amount of APAP a day over 1-2 weeks causes abnormal liver function in blood work.
http://www.newstarget.com/019555.html The inhibited mucus production makes sense, since NSAID's are contraindicted for people with asthma.
FOLLOW THESE INSTRUCTIONS AT YOUR OWN RISK, IF YOU MESS IT UP AND END UP WITH LIVER DAMAGE, IT IS YOUR OWN FAULT.
However, I'd still take an opioid over an NSAID or APAP in any situation. I usually take small amounts (30-60mg) of Codeine Phosphate for various pains. It's pretty easy to get ahold of, and tiny amounts (8mg) are availible over the counter, at least in Europe. They are usually coupled with an NSAID (most commonly Ibuprofen), Aspirin, or APAP. All 3 secondary substances are easily seperated from the Codeine with a cold water extraction. Grind the pills up into a fine powder, add the powder to a small amount (half a shot or so) of warm water (from the hot tap, not boiling water as this breaks down the Codeine Phosphate) to help the powder dissolve. Stir every now and then until all of it has dissolved. Then stick this in the refrigerator and cool (5C recommended if your source contains APAP or Ibuprofen). Once cooled appropriately, you should have a chalky liquid on the top, and a thick white sludge at the bottom. The sludge is your secondary substance. Discard of the sludge by filtering the liquid through a t-shirt, coffee filter, or even better, a micron filter, until there is little to no sludge left. Hold your nose, get something sweet to chase it with, and down the remaining liquid. Codeine Phosphate is very bitter, so it is neccessary to chase it with something sweet to overpower the aftertaste.
This process works because APAP and Ibuprofen are NOT soluble at lower temperatures, however Codeine Phosphate is fully soluble at lower temperatures. It's a very simple process. It may seem like alot of effort, but it's not too difficult to make many batches of the substance to use when needed. It stores fine in the refrigerator and is quite stable at the temperatures the refrigerator maintains. Side effects of Codeine Phosphate may include constipation, vasodilation, bradycardia, increased cranial pressure (as an effect of the vasodilation I presume), drowsiness (at higher doses), nausea, respiratory depression and lowered blood pressure. Codeine is converted to Morphine in the liver by CYP3A4, and is catalysed by CYP2D6, so if you are taking an inhibitor to any of these enzymes, the effects of the substance will be greatly reduced. Inhibitors include any of the SSRI-class anti-depressants (Fluoxetine, Paroxetine, Citalopram, Escitalopram, and to a much lesser extent, Sertraline). The analgesia is pretty powerful for an over-the-counter substance, and can't be matched by an NSAID, let alone APAP. Just offering my "alternative" to the traditional OTC analgesics :)
If the above breaks any rules, please edit it out mods.
EDIT: And for your enjoyment..
http://youtube.com/watch?v=2-hcF8jD5qM :D
