Many people take non-steroidal anti-inflammatory drugs (NSAIDs) without having any side effects. They can be a very effective form of treatment and are widely used to treat a number of conditions.

However, it is important to remember that any medicine can carry a risk of side effects. In a small number of cases, the side effects of NSAIDs can be extremely serious. So if you are taking NSAIDs for a prolonged period of time, or in high doses, your reaction to the medication should be monitored.

Some of the side effects that can be caused by NSAIDs are described below.

Common side effects

NSAIDs most commonly affect the gastrointestinal tract (the stomach and intestines). Common side effects associated with the long-term use of NSAIDs include:

• indigestion 
• stomach ulcer (a sore in the lining of the stomach)
• increased blood pressure

Stomach ulcers can sometimes cause more serious complications, such as:

• gastrointestinal bleeding – internal bleeding within the digestive system
• anaemia – where blood is unable to carry enough oxygen around your body which can cause shortness of breath and tiredness
• gastrointestinal perforation – where a hole occurs in the wall of your stomach or intestines

Less common side effects

Research has found that taking NSAIDs on a daily basis causes persistent headaches in around one in 10 people.

Some types of NSAID can make people feel drowsy or dizzy. If you have these side effects while taking an NSAID, avoid driving or using tools and machinery.

Rare side effects

In rare cases, NSAIDs can affect your heart and the rest of the circulatory system. Side effects can include:

• heart failure – the heart is having trouble pumping enough blood around the body
• heart attack 
• hypertension (high blood pressure that needs treatment)
• stroke
• making pre-existing inflammatory bowel disease (IBD) worse

Although these side effects are potentially very serious, it is important to note they are rare and most likely to affect someone who has an existing cardiovascular condition.

This is why NSAIDs are not usually recommended for people with a history of these types of condition.

If the use of an NSAID is thought to be vital, then naproxen is thought the safest choice when taken alongside a PPI or H-2 antagonist.

Additionally, NSAIDs may affect your liver or kidneys. Again, this only happens in a small number of cases, and is most likely to affect those with existing liver or kidney conditions.

Allergic

An allergen is a substance that reacts with the body's immune system and causes an allergic reaction.

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Kidney

Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.

Stomach

The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.

Stools

Stool (also known as faeces) is the solid waste matter that is passed from the body as a bowel movement.

Ulcers

An ulcer is a sore break in the skin, or on the inside lining of the body.

Vomit

Vomiting is when you bring up the contents of your stomach through your mouth.