We commonly use paracetamol in our daily life. What is paracetamol? Paracetamol is also known as acetaminophen. Paracetamol is belongs to a group of pain-killers or aniline analgesics. Paracetamol is an organic compound that consists of a benzene ring core that substituted with one hydroxyl group and the nitrogen atom of an amide group in the 1,4 para pattern. The amide group in the paracetamol is the acetamide.
There are few ways of administration of paracetamol into the body such as the oral route, intravenous, rectal route and enteral route. Oral route is the process by delivering the paracetamol by the mouth through the alimentary tract. Oral route can be divided into two types which are oral suspension and the oral tablets. Intravenous is placing an appropriate dose in the syringe and directly injected into the vein. Rectal route is by removing the foil wrapper of paracetamol and insert well up into the rectum. The absorption of the rectum is better compared to the others because the rectum is full of blood capillaries. Enteral route is crushing the oral tablets and mixing with water prior to enteral feeding tube administration may be suitable alternative to liquid formulations of acetaminophen. Below are the pictures for oral suspension and oral tablets of paracetamol:
The uses of paracetamol
Paracetamol is used mostly for pain reliever and fever reducer. Besides that, there are many uses for paracetamol too such as to treat headache, muscle aches, arthritis, backache, toothaches and colds. However, paracetamol does not have any effect on the inflammation and swelling of the joint. Paracetamol can also be used in more severe pain such as a post-surgical pain and palliative care is provided for advanced cancer patients.
Paracetamol should not be used overdose. The first symptoms of using overdose paracetamol are:
- Loss of appetite.
- Nausea.
- Vomiting.
- Stomach pain.
- Sweating.
- Feel pain in the upper stomach.
- Thick concentration of urine.
- Yellowing on the skin.
- Barbiturates, also known as sleeping pills.
- Tricyclic antidepressants.
- Colestyramine, used to treat high cholesterol.
- Warfain, used to thin the blood and prvent blood clotting.
- Zidovudine, used in the treatment of HIV infections and AIDS.
- Domperidone and metoclopramide, used to cure nausea and vomiting.
- Anticonvulsants, used in the treatment of epilepsy.
- Oral contraceptives pills.
Side effects of using paracetamol
Paracetamol is a harmful medicine if overdose. There are few side effects of using paracetamol. One of the side effects is will cause liver and kidney damage when is overdose. Toxicity of paracetamol arises due to the quinone metabolite. As the toxicity of paracetamol increases without control may cause death within few days. Another side effect is will cause hypotension if paracetamol is given through blood infusion in a high dose that recommended. To avoid the absorption of paracetamol after an overdose condition, activated charcoal will be used so that the can lower down the absorption of the paracetamol.
Brands for paracetamol
There are many brands name of paracetamol in different countries. In Malaysia, paracetamol is known as Panadol. Another brand name of paracetamol in Malysia is Uphamol. Panadol is also a brand name of paracetamol in many countries not only in Malaysia such as United States, Australia, Hong Kong, Indonesia, Taiwan. Turkey, Ireland, Sri Lanka, Switzerland and many more. Our neighbour, Thailand has a different brand name for paracetamol which is called as Sara. There are many other brands name in other countries such as Zolben, Tapsin, Scanol, Revanin, Reliv, Plicet and Etpara.
Precaution of paracetamol
Paracetamol should be stored carefully because paracetamol is harmful and cannot be taken frequently. Besides that, paracetamol should be prevented from the light and always alert with the expiry dare so that eating expired paracetamol could be avoided. Paracetamol should be kept out of the reach of the children and stored in a original package in a temperature below 25°C.
This is the skeleton structure of the paracetamol.
Metabolism of paracetamol
Paracetamol is metabolisms in the liver first and then transforms into toxic or non toxic products. There are three metabolism pathways. The first pathway is glucuronidation reaction. This reaction can accounts around 40% to two-thirds of the metabolism of paracetamol. The second pathway is the sulfation which can account around 20% to 40% of the metabolism. The last pathway is the n-hydoxylation and rearrangement and then proceeds to GSH conjugation reaction. This reaction accounts less than 15% of the metabolism of paracetamol. The products from all the three pathways that are inactive and non-toxic will be excreted from the kidneys. In the n-hdroxylation and rearrangement reaction and continues with GSH conjugation reaction will produce an intermediate product which is known as NAPQI. This intermediate product is very toxic and responsible for the toxic effects of paracetamol. In usual doses, NAPQI can be detoxified by conjugation with glutathione. However, in overdoses, NAPQI becomes saturated and accumulated and this can cause liver and renal toxicity.
Preparation of paracetamol
Paracetamol can be prepared in laboratory by using nitrating phenol with sodium nitrate. The reaction occurs when para-nitrophenol is separates from the ortho-byproduct and reduces to the nitro group with sodium borohydride. The product is 4-aminophenol. Phenol is a strongly activating reagent, therefore the reaction only requires mild conditions.
Issue related to paracetamol
There have been an issue saying
that paracetamol found to be linked to blood cancers. This article was written
on the 11 May 2011 by Daily Mail Reporter. It was said that regular users of
paracetamol increased the risk of developing blood cancers such as lymphoma,
myelodysplastic syndrome or MDS, found by the researchers. Paracetamol that
contained acetaminophen has been linked to cases of blood cancers in a number
of individuals who were frequently took the paracetamol. In the earlier work,
acetaminophen is also linked to asthma and eczema, but scientist did not
confirm whether acetaminophen is the actual culprit or the innocent bystander.
There has been a research in Washington State about the often use of
paracetamol. The scientists followed around 65,000 older women and men for the
research of the participants about their use in of paracetamol over the past
ten years and made sure that no one had cancer except for skin
cancer. According to Emily White of the Fred Hutchinson Cancer Research
Centre in Seattle, who worked on the new research said that a person who is age
50 and above has about one percent risk in ten years of getting one the blood
cancers. Their studied suggested that if acetaminophen are used four times a
week for at least four years, as a result the risk of getting blood cancer will
be increased to about two percent. Over some six years on average, less than
one percent from 65,000 older women and men or about 577 people were developed
a blood cancer. More than nine percent of people who developed one of the blood
cancers frequently used acetaminophen compared to five percent of people who
did not sick. A cancer prevention expert at the University of Texas MD Anderson
Cancer Centre in Houston, Dr. Raymond DuBois said that acetaminophen worked very
differently than other painkillers and assumed that might have a different
effect on cancers. However, Emily White said it is too soon to make any
recommendations based ob the new study and none of the painkillers are free of
side effects. Long-term use of any drugs might have adverse effects too.