What are painkillers?

Painkillers are substances that are used to relieve or reduce pain. Pain can be classified in different ways. For example, there is acute pain, such as spraining your ankle, or chronic pain, such as nerve damage.

There are also many different types of pain: headache, muscle pain, nerve pain and wound pain. In addition, pain can feel very different for each cause, such as stabbing pain, burning pain, throbbing pain, dull pain and spastic pain (cramps).

Due to the wide variety of pain and because people often react differently to certain drugs, there are many different types of painkillers on the market. The most powerful type are the opioids; these can cause problems such as addiction and overdose.

Other names for painkillers

Pain relievers, tranquilizer, medicine, sedative, alleviative.

Types of painkillers


Paracetamol is the most used analgesic and fever-lowering drug in the world. Paracetamol relieves pain  because it is an inhibitor of certain forms of cyclooxygenase (COX), an enzyme that converts arachidonic acid into prostaglandins (stimulate the feeling of pain). However, the exact working mechanism has not yet been clarified. Paracetamol is a relatively safe medicine and can also be used during pregnancy.


NSAIDs (non-steroidal anti-inflammatory drugs) are anti-inflammatory drugs that do not belong to the corticosteroid group. The analgesic effect is based on the inhibition of prostaglandin synthesis in the body. The prostaglandins have a function in feeling pain, they stimulate the feeling of pain. In addition, they also have an effect on the protective effect of the gastric mucosa. This can cause stomach irritation or bleeding when using NSAIDs. Aspirin was the first drug from this group that was ever discovered. Commonly used NSAIDs include ibuprofen, diclofenac and naproxen.

COX-2 inhibitors

A COX-2 inhibitor is also an NSAID pain reliever. However, it selectively inhibits the COX-2 enzyme, which is responsible for inflammatory responses and pain, in contrast to traditional NSAIDs that specifically inhibit both COX-1 and COX-2 enzymes. By only inhibiting the COX-2 enzymes, the risk of a stomach ulcer is considerably smaller than with these traditional NSAIDs. Agents that work in this way include celecoxib, rofecoxib (Vioxx®) (which has since been withdrawn from the market due to cardiovascular side effects) and etoricoxib (Arcoxia®).


Opioids are painkillers based on opium-derived substances. These exert their effect on opioid receptors, which occur in the brain, spinal cord and the peripheral nervous system. Morphine is the best known in this group. Other commonly used morphinomimetics include codeine, oxycodone, fentanyl, pethidine and tramadol.


The Cannabinoids are a group of substances that activate the cannabinoid receptors in the brain and nerves. This causes, among other things, an analgesic effect in humans. Cannabinoids can, among other things, be obtained from the hemp plant. It contains many pharmacologically active ingredients, most of which have either analgesic or anti-inflammatory effects. There are also endocannabinoids that have analgesic and anti-inflammatory properties, such as the body’s own molecule palmitoylethanolamide.

How to use painkillers

Painkillers can be used in various ways depending on the purpose and type of painkiller. The most common way is to swallow a pill. This is done, for example, with acetaminophen, aspirin and opioids.

To achieve a faster effect it is also possible to opt to inject it. This way it works immediately and less of a substance is needed.

There are also plasters that release a painkiller slowly, ointments that numb locally, nasal sprays for rapid action and you can also inhale certain painkillers, for example for anaesthesia.

Effects of painkillers

The function of all different painkillers is primarily to reduce pain. People often get prescribed by a doctor to combat pain.

Some painkillers, such as opioids, also have a intoxicating effect. You become relaxed and lazy and you feel comfortable. You forget your worries for a moment and you become numb, as with alcohol. You get into a dreamy state. This means that these drugs can also be very addictive.

Even drugs that do not have a intoxicating effect can be addictive. For example, if you use paracetamol for a long time, your body can get used to it and at some point you will no longer be able to live without it.

Opioid pain killers also have the following physical effects:

  • Heart rate goes down.
  • Breathing is slower.
  • Body temperature goes down.
  • Pupils are getting small.
  • Gut motility decreases.
  • Bladder sphincter becomes a little numb.
  • Sexual needs are declining.
  • User has trouble with faeces and urinating.
  • Menstruation may become irregular in women.

Addiction risk painkillers

About 9 out of 10 people sometimes use a painkiller. Most people use this for the headache or back pain.

Many people use no more than the prescribed amount and have no problems with it. Yet there is a group that is overused and addicted to resources. Opioids in particular are very addictive, but also addiction to paracetamol and NSAIDs occurs.

Painkillers can have a paradoxical effect, which increases the risk of addiction. When prolonged painkillers are swallowed due to headache symptoms, it may be that at some point the painkillers themselves cause a headache. These headache complaints come on top of the complaints for which the painkillers were initially swallowed. Thus, a higher dose is always needed and a dependence can arise.

When people are addicted to an opioid pain reliever, it can be very difficult to get rid of it, usually this does not work without guidance. Due to the similar effect, an opioid painkiller addiction can resemble a heroin addiction (hyperlink naar heroin in het engels)

Risks of painkillers

In addition to the risk of addiction (see addiction risk), there are the following risks:

  • Loss of work / social contacts: Taking opioids makes you drowsy and less social. This can lead to you leaving the door less and less and getting into isolation.
  • Organ problems: Unsafe use of painkillers such as diclofenac, ibuprofen and naproxen increases the risk of stomach bleeding, heart problems and kidney damage.
  • Traps and other accidents: Opioid swallowing reduces your concentration and coordination. Because of this you run a greater risk of accidents. The number of accidents is particularly high among older opioid users.
  • Not noticing that you have illnesses: Opioids suppress pain so that certain symptoms are not felt or are felt too late and therefore unnecessarily aggravated.
  • Not noticing when pregnant: In a woman who uses opioids, menstruation is often irregular or stays away. But she can get pregnant. This pregnancy is often only discovered at an advanced stage.
  • Physically dependent babies: A new born baby of an opioid addict is physically dependent and develops withdrawal symptoms. In the beginning the baby cries a lot, is frightened and often wakes up. There is also a chance of developmental disorders.
  • Overdose: The most dangerous risk in the short term is the risk of overdose. Breathing may come to a halt. Users with an overdose look limp and pale. They breathe slowly or not at all. Sometimes they have foam on their lips, they vomit or have epileptic seizures.

Reduce risks

The best way to reduce the risk is to stick to the prescribed dose and to not use it for a long time. As soon as you notice that you are using more than the dose prescribed by a doctor, it may be a sign that you are developing a dependence. As soon as your pills run out earlier than they should, contact your doctor.

Read well in advance about the risks of the resources you take. And together with your prescribing doctor, try to prevent use from getting out of hand.

How long is it visible?

This depends on the type of painkiller used. The most drugs will disappear from your blood within 3 days. Depending on the extent of use, some opioids may be detectable in the urine for up to 5 days.

Painkillers and the law

Most painkillers such as paracetamol and a number of NSAIDs can be purchased in a drugstore, pharmacy or supermarket without a doctor’s prescription. You will need a doctor’s prescription for some other NSAIDs.

All opioids are on list 1 of the Opium Act because of the strong intoxication effect. For a few exceptions you always need a prescription from a doctor.

Painkillers and traffic

With paracetamol it is no problem to participate in traffic. NSAIDs can make you a little dazed. If you notice this, do not participate in traffic. Also be careful if you drink something alcoholic. Paracetamol and NSAIDs can enhance the drowsiness of this.

With opioid pain killers it can be dangerous to hit the road. Opioids have a diminishing effect and cause your responsiveness to deteriorate. This can differ per type of opioid and per disorder. Always consult your prescribing doctor first before you participate in traffic.


Versie: april 2020