Over-the-counter painkillers

Published by Bupa's Health Information Team, February 2010.

This factsheet is for people who would like information about taking over-the-counter painkillers.

Over-the-counter painkillers are pain-relieving medicines that can be bought from a pharmacy or shop, without a prescription from your doctor. They include paracetamol, ibuprofen and aspirin.

Why would I take over-the-counter-painkillers?

You can take over-the-counter painkillers to relieve a variety of common aches and pains, including headache, muscle and joint pain, backache, toothache and period pains.

Over-the-counter painkillers also lower a high temperature caused by an infection such as a cold or flu. Some painkillers, called non-steroidal anti-inflammatory drugs (NSAIDs), can also reduce inflammation. So they are particularly useful for pain associated with inflammation, such as arthritis and muscle sprain. NSAIDs that you can buy without a prescription from your doctor include ibuprofen and aspirin. You can also buy some low-dose forms of diclofenac and naproxen from a pharmacist.

How do over-the-counter painkillers work?

Over-the-counter painkillers act by working on chemicals in the body known as prostaglandins. These chemicals are part of your body's defence response - they are responsible for the sensation of pain and for causing the high temperature when you have a fever, and are also involved in the process of inflammation. Your body produces prostaglandins in response to damage or inflammation and they are picked up by nerve cells, which send pain signals to your brain.

NSAIDs block a chemical in your body (an enzyme) called cyclo-oxygenase (COX), which helps to make prostaglandins. As a result, the damaged or inflamed tissue in your body produces less prostaglandins, and your inflammation, pain or fever is reduced. Paracetamol is also thought to act on the prostaglandins, helping to prevent pain and fever. However, it doesn't have the same anti-inflammatory effects of the NSAIDs and it is still unclear exactly how it works.

Aspirin is different from other painkillers, as it has a number of other effects in addition to relieving pain. It also works in a different way to help 'thin' the blood and reduce the risk of blood clots. This is why doctors often prescribe aspirin if you have a heart condition.

How to take over-the-counter painkillers

Over-the-counter painkillers come in various different forms. These may include:

• tablets, caplets (longer, round-ended tablets that may be easier to swallow) or capsules for swallowing
  
• a powder or tablet to dissolve in water
  
• liquid/syrup
  
• gels that you rub onto your skin and patches that you place on your skin

You can buy over-the-counter painkillers from a pharmacy, supermarket or other shop such as a convenience store, without a prescription from your doctor. Aspirin and paracetamol are limited to packets of up to 16 if you buy them in a shop without a doctor's prescription, to help prevent people from accidentally taking too many. However, you can buy them from pharmacies in packs of up to 32 tablets.

You should always read the patient information leaflet that comes with your medicine, and take your medicine as directed. Do not exceed the recommended dose. For paracetamol, this is 500mg to 1000mg for adults (usually one or two tablets, depending on tablet size), every four to six hours, with a maximum of 4000mg in 24 hours. That usually means a maximum of eight tablets in one day, but make sure you check the size of your tablets.

For ibuprofen, the recommended dose for adults is 400mg (usually two 200mg tablets), three to four times a day. For aspirin, it is 300mg to 900mg every four to six hours, with a maximum of 4000mg in 24 hours. You may be advised to take oral NSAIDS with or after food or milk, as this makes it less likely that they will cause stomach problems. NSAID creams or gels can be rubbed into your skin three or four times a day. You shouldn't apply them to broken or infected skin, near your eyes or mouth, under plasters or dressings, or in the same place as other skin creams or lotions.

Over-the-counter painkillers are only meant to be taken occasionally - unless advised otherwise by your GP. If you are finding you need to take painkillers for a long period of time, or they are not helping with your pain, you should see your GP.

Taking too much

A paracetamol overdose is particularly dangerous because it causes liver damage, which may not be obvious for up to four days after the drug has been taken. Even if someone who has taken a paracetamol overdose seems fine and doesn't have any symptoms, it's essential that they are taken to hospital urgently. An overdose of paracetamol can be fatal.

Many cold and flu remedies often contain a painkiller, sometimes in combination with other medicines, such as codeine or a decongestant. So it's very important that you count the amount of painkillers in all the medicines you have taken.

Children and painkillers

Paracetamol and ibuprofen are suitable for pain relief and reducing a fever in children. However, you should only give paracetamol or ibuprofen to babies under the age of three months if advised to by a doctor or nurse. The doses for children depend on their age and weight and are clearly given on the medicine's container. There are special formulations of paracetamol and ibuprofen available for children, such as syrups and dissolvable powders, which may be easier for children to take.

Aspirin is not suitable for children under the age of 16, as it has been linked to a condition called Reye's syndrome.

Special care

You shouldn't take ibuprofen or aspirin if you have severe heart failure, if you have ever had a stomach or duodenal ulcer, or if you have previously had a reaction to any NSAID.

You should also check with a pharmacist or doctor before taking aspirin or ibuprofen if you:

• have asthma
  
• are over 65
  
• have poor kidney or liver function
  
• are pregnant or breastfeeding
  
• are taking tablets for high blood pressure

You should check with your doctor or pharmacist before taking paracetamol if you have kidney or liver disease. Paracetamol is not known to be harmful in pregnancy. As with any drug though, it's best to talk to your pharmacist or doctor before taking it. Very little paracetamol gets into breast milk so it's usually safe to take if you're breastfeeding.

Side-effects of over-the-counter painkillers

You're unlikely to get side-effects from taking over-the-counter painkillers occasionally and at the recommended dose.

The most common side-effects of NSAIDs such as aspirin and ibuprofen are effects on the stomach, such as feeling sick, vomiting, abdominal pain, indigestion and diarrhoea. These effects are less common with ibuprofen than with other NSAIDs. Aspirin can also be associated with bleeding from the stomach, which can cause you to vomit blood or pass blood in your faeces. If you have these symptoms, you should contact your GP immediately.

If you have asthma, NSAIDs can make you more likely to have an asthma attack. They can also cause allergic skin reactions in some people.

Side-effects of paracetamol are rare when you take it at the recommended dose, and one advantage of paracetamol over NSAIDs is that it doesn't affect your stomach. However, very rarely, some people have an allergic skin reaction after taking paracetamol. Paracetamol can cause serious liver and kidney damage if you take too much.

This section does not include every possible side-effect of over-the-counter painkillers. Please read the patient information leaflet that comes with your medicine for more information.

Interactions

Talk to your doctor or pharmacist if you take an anticoagulant medicine such as warfarin, for heart problems, before taking paracetamol or an NSAID. Paracetamol and NSAIDs can increase the blood-thinning effects of these medicines. So your doctor may advise you not to take them, or he or she may adjust your usual dose of your anticoagulant medicine before you take them.

Names of common over-the-counter painkillers

All medicines have a generic name. Many medicines also have one or more brand name. Generic names are in lower case, whereas brand names start with a capital letter.

Over-the-counter painkillers are often combined with other medicines such as codeine or decongestants in pain-relieving products or cough and cold remedies. Some of these can only be prescribed by a doctor. Here we list products containing paracetamol, ibuprofen or aspirin, which you can buy without a prescription from your doctor. This is not a comprehensive list of products. Many supermarkets and shops also sell 'own brand' versions.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.