Medication: Paracetamol

Examples of branded paracetamol: Panadol®

Examples of generic products for paracetamol

Introduction

       "Panadol^®", which consists of paracetamol (name used in UK) or acetaminophan (name used in US), is a commonly used brand in the current market. Almost everyone is aware of the existence of this medication due to its extensive advertisement in the television and internet with its original brand name "Panadol^®". But how well do you know about this medication?

       Paracetamol, which is usually available as a 500mg/650mg tablet, syrup or suppositories, is indicated for fever or as a mild painkiller. Paracetamol may be combined with other medications to provide a 3-in-1 effect, for example, with pseudoephedrine and chlorpheniramine for congested and running nose symptoms, or with codeine/tramadol as a stronger painkiller.

       For adolescents (age more than 12 years old) or adults with normal kidney and liver function, the maximum tolerable dose of paracetamol will be 4000mg or 4g (e.g. 2 tablets of 500mg paracetamol, 4 times a day or 1 tablet of 650mg paracetamol 6 times a day). Paracetamol can be taken with or without food. For infants to children dosing, please refer to the external labeling of the paracetamol syrup.   

        I believe this brief introduction provides you a better understanding on paracetamol. Now, I would to clarify some of your doubts and myths regarding this medication, namely paracetamol.

Doubts and Myths

1. Will all painkillers, including paracetamol, lead to gastric problems?

Painkillers, such as non-steroidal anti-inflammatory drugs (NSAIDs), will have a higher risk of gastric problems due to their acidic properties in nature. However, paracetamol is a very weak acid compared to NSAIDs and hence it is very unlikely to cause gastric problem even it is being given on an empty stomach.

2. Will long-term intake of paracetamol damages the liver and kidney?

There is a report showing that paracetamol under recommended dosing can cause liver dysfunction which is very rare (less than 1/10000). As long as paracetamol is taken as instructed, it will not lead to liver damage. There are no evidences showing that paracetamol can lead to kidney damage. However, paracetamol should be used with caution in patient with impaired liver and/or kidney function. 

3. Why do I develop rashes after I take paracetamol?

There may be chances that you will be allergic to paracetamol although the chances are very rare (less than 1/10000). It is considered as mild allergy, if you develop rashes after taking it. For a more severe allergic response, the patient might develop difficulties in breathing. For patients who might develop mild allergies, it will be advisable to choose other medications over paracetamol as discomfort may still occur.

 4. Will paracetamol stay in my body forever?

The elimination half-life of paracetamol varies from 1 hour to 3 hours. But first of all, what is half life? Elimination half-life basically refers to the time required to eliminate half the amount of drug from the body (eg. from 100% to 50%). It takes around 5 half lives to eliminate almost all of it. So hence, paracetamol takes around 5 to 15 hours to be completely being eliminated from the body. Therefore, the myth regarding that paracetamol will stay in the body forever is not true!  

The elimination half-life of paracetamol (1 to 3 hours) also explains why the patient has to take paracetamol every 4-6 hours. For medication with long elimination half-life (eg. 12-18 hours) may explain why that particular medication just requires once daily intake.

5. Will paracetamol cause cancer?

There are researches showing paracetamol could post a risk in developing blood cancer but it is yet to be confirmed. 

6. Can I take paracetamol if I am pregnant or breastfeeding?

Paracetamol is categorized as Pregnancy Category A. This means that Paracetamol has been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations. Hence, it is considered safe to be taken as normal dose by pregnant woman, regardless of the pregnancy trimester.

Paracetamol will be excreted in breast milk but the amount exposed to the infant is less than 0.1% of a single dose of paracetamol 500 mg and as 0.04 to 0.23% of a single 650 mg dose. Hence, as long as the breastfeeding mother is taking the paracetamol without exceeding the recommended dose, it will not be a risk to the breastfed infant.

7. What is the difference between Panadol^® and other brands of paracetamol?

Panadol^®, is the original brand of paracetamol, it is manufactured and patented by GlaxoSmithKline (GSK). Other brands, such as Paracil^®, Dymadon^®, Febridol^® and Paralgin^®, are generic brands patented by other companies. All of them contain paracetamol as the active ingredient but their excipients (inactive ingredients, such as preservatives) can be different. The generic brands of paracetamol have to meet with the requirement of bioequivalence before they are released into the market. If two products are said to be bioequivalent, it means that they would be expected to be, for all intents and purposes, the same.

8. What should I do if a person exceeded the recommended dosage of paracetamol?

Paracetamol overdose may cause liver failure which can lead to liver transplant or death.

If an overdose is confirmed or suspected, the National Poisons Centre should be contacted immediately for advice. The patient should also be sent to a hospital as soon as possible, even if there are no symptoms of overdosing as there is a risk of delayed, serious liver damage.

National Poisons Centre (in Malaysia)

Office Hours              : 1-800-88-8099 / +604-657 0099
(Monday-Friday: 8.10am-5.10pm)

After Office Hours    : +6012-430-9499

(Including weekends and public holidays)

The Author

Jordy Wong Der Yuan

BPharm (Hons) (IMU)

Date: 27/3/2016

Editors

Chang Jen Nee, Ong Jijien