Sep 2, 2019

5 min read

3 Common fever medicines - How they work and how to use them safely.

Fevers are an irksome but unavoidable part of all our lives. We’ve all had those stubborn, obstinate fevers that leave us miserable and reaching for our drug cabinet. Having said that, fevers for the most part, are harmless and don’t necessarily pose any real threat to our health and wellbeing.

So, Why treat them at all?

While it is true that fevers are a normal physiological response, they do cause significant discomfort and are quite taxing to deal with. The higher the temperature, the higher the discomfort and suffering a person goes through. The toughest of people are reduced to mere shadows of themselves in the face of a persistent fever. And, needless to say, no person can sit back and watch their children go through such misery.

We use fever medication to restore a degree of comfort and help us through fevers, without too much unpleasantness. Therefore, it is vital to understand that fever medicines are prescribed to help us feel better, and not because fevers are dangerous, in any way. This makes it imperative for them to be absolutely safe, because it makes no sense to trade safety for comfort.

Here’s a rundown on the most popular medicines used to combat fever, their mechanisms of action and their potential side effects on the body.


Aspirin is the oldest of all commonly used fever medicines and probably the least well known, due to its more popular use as an antiplatelet and anti-inflammatory (pain killer) drug.

Aspirin, pharmacologically known as Acetyl Salicylic Acid, belongs to the class of substances known as salicylates.

How does it work?

Aspirin, like most antipyretics works against the action of an enzyme called Cyclooxygenase (COX), which is responsible for producing prostaglandins, which result in fever (click here to understand the mechanism of fever production in detail). Aspirin works by completely “blocking” COX receptor sites.

Aspirin specifically targets platelet cells (responsible for blood clotting) with its COX-inhibiting effect (which, in the case of aspirin, is irreversible).

Is it safe?

Although aspirin is almost universally recognised as a safe antipyretic for adults, most authorities do NOT recommend using aspirin to treat fevers in children. This is because aspirin use has been linked to higher incidence of a dangerous illness called “Reye’s disease”, in children.

Other adverse effects include gastric disturbances, rashes and ulcers, although they are rare.

Interesting Fact:
Thanks to its vasodilatory (widening of blood vessels) property, a small, daily dose of aspirin is widely prescribed for patients who’ve had recent heart attacks and strokes, to prevent repeat episodes.It was also fortuitously found to reduce risk of colon cancer.


Paracetamol (Acetaminophen/Tylenol) is one of the most widely used antipyretic drugs. It was first isolated in 1893, from coal tar, in Germany.

Paracetamol is widely available over-the-counter and is considered a drug of choice for treating mild to moderate fevers. Although it does have anti-inflammatory (pain relieving) effects, they are very mild compared to the other drugs mentioned here.

How does it work?

Unlike other NSAIDS (Non-steroidal Anti Inflammatory Drugs) such as aspirin or ibuprofen, paracetamol does not have any effect on cyclooxygenase (COX), outside the central nervous system.

It is an enduring marvel in the medical world that despite being in use for well over a century, we do not understand the precise mechanism of this drug’s action. Its effects have been linked to several pathways such as the endocannabinoid system and the serotonergic system, but no conclusive proof has been established so far. It has been proven to affect the production of COX in the brain, which contributes to its fever reducing properties.

“A study conducted by the Norwegian Institute of Public Health in 2016, found that paracetamol exposure in the prenatal (before birth) period or use during infancy correlated with a 30% higher chance of asthma at age 7.”

Is it safe?

At doses not exceeding 4g/day (for adults; usually <1g/day max, for children), paracetamol is widely recommended as a safe drug for treating fevers.

However, it has been linked to a number of adverse effects. At doses approaching 15g or higher, it causes severe toxicity and often results in death from liver failure.

Additionally, a study conducted by the Norwegian Institute of Public Health in 2016, found that paracetamol exposure in the prenatal (before birth) period or use during infancy correlated with a 30% higher chance of asthma at age 7.

Nevertheless, post-infancy, paracetamol can be safely used to treat fevers and mild pains, at recommended doses, without any fear.


Ibuprofen is a well known medication commonly used to treat fevers and pains. It belongs to a class of drugs known as NSAIDS. It is popularly known by the brand name “Advil”.

How does it work?

Much like other anti-inflammatory drugs, ibuprofen works by blocking COX receptor sites and as a result, blocking the production of a group of fever producing substances called “prostaglandins”.

Unlike paracetamol, which works exclusively in the brain, ibuprofen acts on COX sites all over the body (explaining its widespread use as a pain killer).

Is it safe?

Ibuprofen has been shown to be a safe drug, when not used regularly. However, with chronic use in high doses, it has been linked to some adverse effects, such as gastric/intestinal bleeding and increased risk of heart disease.

It is also important to note that, ibuprofen is NOT to be given to children with asthma, as it has been shown to aggravate the condition.

Do’s and Don'ts

  • Do not use more than one antipyretic drug (eg. paracetamol and ibuprofen) in tandem.
  • Do not use alcohol while you are on any of these medications.
  • Consult your physician before using these drugs, if you suspect that you/your child may have any of the above mentioned contraindications.
  • Never exceed the recommended dose, no matter how high the fever.

About the author

Abishek Swaminathen

Senior Content Manager

Abishek is ONiO’s senior content manager. A medical doctor by profession, he stumbled onto a writing career almost by accident, as it were. Words have enthralled Abishek since the day he first held a book and at ONiO, he channels his inner wordsmith towards providing our subscribers with regular doses of fun and informative content.

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