PANADOL(Pain Killer)

Types of Panadol

"Mummy..i am so sick...i need some Panadols...". I think this phrase is most probably familiar among us. Panadol is a name which is known worldwide and it becomes our 'best friend' when we are in extreme pain. They are available in tablet, capsule, liquid suspension and many other forms. The minute you feel the headache coming on or any other condition that requires pain relief,chances that you reach for a panadol is extremely high. This drug is used to moderate pain and to reduce fever.


Structure and Synthesis
Paracetamols consist of a benzene ring core, substituted by one hydroxyl group and the nitrogen atom of an amide group. The amide group is acetamide. Paracetamol is much easier to synthesize compared to other drugs. It can be easily prepared in the laboratory by nitrating phenol with sodium nitrate. Next, reduce the nitro group with sodium borohydride. The product is then acetylated with acetic anhydride. This reaction requires mild condition as the phenol is strongly activating.

Metabolism
Paracetamol is metabolised primarily in liver, into non-toxic products. There are three metabolic pathways:
- Glucuronidation is believed to account 40% to two-thirds of the metabolism of paracetamol.
- Sulphation (sulphate conjugation) may account for 20%-40%.
- N-hydroxylation and rearrangement, then GSH conjugation, accounts for less than 15%.

The yield of these three pathways are non-toxic and eventually excreted by kidneys. In the third pathway, the intermediate product, NADPI is toxic. NADPI is responsible for the toxic effects of paracetamol.

Main pathways of paracetamol metabolism (click to enlarge). Pathways shown in blue and purple lead to non-toxic metabolites; the pathway in red leads to toxic NAPQI.

Side Effect
On the other hand, it is toxic to our body and harms the liver if we overtook it. Panadol will reside in our body for at least five years. Last week, i saw an article which is related to Panadols and i was shocked by its contents. There used to be an incident where an air stewardess consumes a lot of Panadol during her menstrual as she needs to stand all the time. She is now in early 30's and she needs to wash her kidney(Dialysis) every month.


Hence, do not take more than recommended by doctor.Overdose of Panadol can be harmful and cause severe, even fatal, liver damage. As Panadol is a pain killer, the more Panadol you take, the lesser would be your threshold for pain. Imagine that we keep popping quite an amount of pain killer in our life, we will need much more amount of anesthetic to numb our surgical pain than the average person who rarely takes Panadol during the surgery or operation.


So value your life, think before you pop this familiar pills into your mouth. Thank you.



References:
1)http://www.drug3k.com/drug/Panadol-10298.htm
2)http://en.wikipedia.org/wiki/Paracetamol