Acetaminophen, also known as Paracetamol (IUPAC name: N-(4-hydroxyphenyl) ethanamide), is the most commonly used antipyretic and pain reliever and since 1955 has been available over the counter as a single formulation or in combination with other substances (Sheen et al., 2002). As indicated by the World Health Organization this drug can be used in all the three steps of pain intensity. Being the main drug prescribed for feeble pains, it can be used together with non-steroidal analgesic drugs also to treat pains of moderate intensity. When pain persists or increases, paracetamol is used as an additional analgesic in combination with weak (e.g. tramadol) or strong (e.g morphine, fentanyl) opioids.