I don't know as I would count on 50mg of acetaminophen to take the place of 650mg, two 325mg tablets, but I don't see any harm in giving it a try and seeing if it works. If 50mg works for you so much the better. Why take more than you need.

Of course I wonder how much of the observed drugs effect at very low dosage can be attributed to a placebo effect.

It is an old medics trick when the morphine runs out to substitute an M&M or a vitamin, sometimes blackened with a magic marker, and to talk it up as an extra-special pain pill before solemnly administering it. Of course, in that case, you have a captive audience that is highly motivated to suspend dis-believe and feel it working.

Not that that is a bad thing. Placebos generally don't cause overdoses or dangerous drug interactions. As one writer pointed out: 'Any method that works well without causing harm is, by definition, good'.