Acetaminophen vs Ibuprofen
Ibuprofen and Paracetamol (Acetaminophen), along with Aspirin are chemicals that are used in popular pain killing medicine. Although they have the same end goal of reducing pain, they achieve this using different methods.
Where provincial regulatory bodies require, it is required that documentation be available on all authorized changes to existing
Ibuprofen is more potent than Paracetamol and thus requires that fewer doses or smaller dosages be taken.
Overdose of acetaminophen is serious and can be fatal from liver toxicity, killing about 1% of those who seek treatment due to the delayed effects. In heavy drinkers, regular use of acetaminophen increases liver damage from alcohol. 
Ibuprofen has been assigned by the FDA to pregnancy category C prior to 30 weeks gestation and pregnancy category D at greater than or equal to 30 weeks gestation. Animal studies have failed to reveal evidence of developmental abnormalities. There are no controlled data in human pregnancy. While there are no literature reports linking the use of ibuprofen in pregnancy with birth defects, use of ibuprofen at greater than or equal to 30 weeks gestation may cause premature closure of the ductus arteriosus and prolong labor and delivery. Ibuprofen should only be given during pregnancy when benefit outweighs risk and should be avoided on or after 30 weeks gestation. [Reference: http://www.drugs.com/pregnancy/ibuprofen.html]