Last updated: 16/10/2022

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We are always committed to your health and that of your loved ones, that’s why we want you to be equipped with products that help you soothe any discomfort and pain that prevents you from carrying out your daily activities in an ideal way.

For this reason, we welcome you to ReviewBox and invite you to join us to learn all about painkillers. We know as analgesics the medicines that help to relieve pain, but there are several types and it can be a little confusing to know which one is best for you. We show you the most outstanding ones on the market today and all the information you need to know about them, for the benefit of your wellbeing.

First the most important things

  • When purchasing a painkiller, it is important to know how it works in the body, the correct way to take it depending on the nature of each one, and how safe it is to mix it with other medicines, such as anticoagulants.
  • According to the World Health Organisation, there are 3 categories when it comes to analgesics: non-opioids (for mild pain), weak opioids (for moderate pain alongside non-opioids) and strong opioids (for chronic pain alongside non-opioids). We’ll tell you all about them.
  • Due to the variety of options you can find, it is necessary to know the presentations of each of them and the cases in which they are used, the added components that can enhance their result, the user who will take them, how they are adapted to certain special cases and what symptom you can alleviate with them.

The Best Painkiller: Our Picks

Buying Guide

When it comes to buying or using a painkiller, you may have some doubts, which is why we cannot overlook some important facts about them. Here we help you to clarify some of the most frequent doubts about painkillers.

As well as helping to soothe headaches, they can also reduce toothaches, earaches and other pains. (Photo: Antonio Guillem / 123rf)

How do painkillers work?

When events such as blows, injuries, burns and the like occur, the cells that are damaged in the damaged area release a substance called prostaglandin, which immediately alerts the brain and sends pain sensations to the nerve endings present in that area.

When you take non-opioid painkillers, they act on your cells

When you take non-opioid painkillers, they act on your cells, nerve endings and brain. They aim to decrease or stop the amount of prostaglandin released so that your brain stops sending instructions that are reflected as pain.

Strong opioid, weak opioid or non-opioid painkillers – what should you look out for?

Each of the types of painkillers has its advantages and risks, so here we break them down and explain them in detail. According to the World Health Organisation’s classification, you can find them as strong opioids, weak opioids and non-opioids.

Non-opioids. These form the first analgesic step of the WHO, as they are the least potent and are used in case of mild pain, such as headache, toothache and the like. They have an analgesic ceiling, so after increasing a certain amount of dosage, the relief will not increase. Examples are aspirin, ibuprofen and paracetamol.

Weak opioids. These can be combined with non-opioids if they are not sufficient, to increase the intensity of their effect. They are used for moderate pain and may cause dependence and constipation. These also have a defined analgesic ceiling and can be found in tramadol, codeine, oxycodone, hydrocodone and the like.

Strong opioids. These tend to be the most potent and tend to be used with non-opioids when weak opioids are insufficient for severe pain. Because they are narcotics, they depress the central nervous system during the first few doses. These include morphine, fentanyl, heroin, hydromorphone, among others.

Non-opioids Weak opioids Strong opioids
Application Mild pain Moderate pain Severe pain
Intensity Limited Potent Very potent
Disadvantage They have an analgesic ceiling Analgesic ceiling They are narcotic substances
Some of them Aspirin, ibuprofen, diclofenac, paracetamol, acetaminophen, etc. Tramadol, codeine, oxycodone, hydrocodone, etc. Morphine, fentanyl, heroin, hydromorphone, etc.

How should I take painkillers?

Non-opioid analgesics are usually available over-the-counter (i.e. without prescription) in low doses. They can be used for fever, muscle aches, inflammation (when they have these properties) and other types of discomfort.

However, it is important to be careful about the dose you take. Each of them has instructions that indicate what the recommended dose is and what the maximum daily dose should be. If your discomfort persists and you do not notice any improvement, it is important to consult a medical professional as soon as possible.

Can painkillers be taken with anticoagulants?

Some non-opioid analgesics such as aspirin, ibuprofen, naproxen, among others, may increase the risk of bleeding if the patient is also taking anticoagulants such as Warfarin, Eliquis, Xarelto or Pradaxa.

For this reason, it is recommended to consult a medical specialist before taking painkillers in these cases, and the ideal choice is likely to be acetaminophen in its simple form (without added components such as caffeine or codeine).

Did you know that paracetamol and acetaminophen are the same painkiller drug? You can also find it as acetaminophen

Buying criteria: factors that allow you to compare and rate different models of painkillers

There are a number of things to consider before choosing a pain reliever for you. There are different presentations, added components and other factors that will determine which option is recommended in each case.

  • Presentation
  • Added components
  • User
  • Special cases
  • Symptom


You will find painkillers in various forms, but the most common ones will always be pills, sprays and ointments. Here we will tell you a little about them and in which cases they should be used.

Pills. These are the most common form you will see. You can find acetaminophen, aspirin, among others. Depending on the dosage and presentation, you will need to take 1 or 2 of them every 6, 8 or 12 hours, and they are useful in case of localised pain, muscular pain, fevers and more (depending on their nature).

Sprays. These are the most commonly used when it comes to pets, thanks to the convenience of their use and the immediate (localised) relief they usually provide. They can be used in case of itching, irritation, inflammation and pain in specific areas, according to the product instructions.

Ointment or gel. Usually used for inflammation, rheumatic and traumatic pain, such as those caused by sprains and lumbago. They should usually be applied with a gentle massage to spread the amount of product evenly. It is available for both human and pet use.

Added components

Some analgesics include, in addition to their analgesic base, other elements that help to enhance their effect or make them more suitable for certain occasions. Here are some of the most common variants. Remember that in all cases it is important to consult your doctor before purchasing.

Codeine. Acetaminophen can be found together with codeine for more effective relief of moderate pain, or in cases of severe coughing. This component is a weak opioid analgesic that is usually taken by mouth. It is important that it is prescribed by a specialist to monitor any side effects.

Caffeine. Studies have found that caffeine can help provide a better analgesic effect alongside drugs such as ibuprofen and paracetamol, as it allows faster absorption of these drugs. At the same time, it has a stimulating effect on the nervous system (which occurs when drinking coffee).

Muscle relaxant. These components (such as carisoprodol) have a good effect together with analgesics (such as naproxen) in relieving discomfort such as muscular pain, inflammation and tension in localised areas, thanks to their antispasmodic effect.


Before selecting an analgesic, it is important to know who will be its frequent user in order to take into account their limitations and possible reactions to the medicine. In this case, we will divide the category into adults, children under 12 and pets.

Adults. Most non-opioid analgesics can be used freely in adults (following the recommended doses) unless there is some context that warrants a better review of the medicines to be taken, such as pregnancy, breastfeeding, hypertension, diabetes and the like (more on this later).

Children. Not all non-opioid analgesics are suitable for children. In cases such as fever, headache or pain caused by shock or infection (e.g. ear infection), acetaminophen is often used as a safe option, always following paediatric indications.

Pets. Medications such as aspirin, ibuprofen, ketoprofen and naproxen are also used to relieve pain in pets such as cats and dogs. They can be administered orally, parenterally, respiratory and topically, the latter being the most common when there is superficial discomfort such as itching and irritation.

(Featured image photo: olegdudko / 123rf)