Duplication or reproduction of existing classified information is not derivative classification. Persons who apply classification markings derived from source material or as directed by a classification guide need not possess original classification authority. (b) Responsibility.
According to my doctor, 4 hours. You can switch them up. Take acetaminophen, (Tylenol), then wait 4 hours and take Ibuprofen, wait another 4 hours and take acetaminophen and so on. :) 15 people found this useful.
This is how fast an appreciable serum level after oral intake of ibuprofen is reached: So those levels would be reached after 15 to 40 minutes of one taking ibuprofen by mouth, faster if combined with an antacid e.g. magnesium oxide, Tums, or whatever.