How do NSAIDs work?

If you’ve ever reached for a pain relief gel after a sore back, taken ibuprofen for a headache or used something anti-inflammatory for a sports injury, you’ve probably used an NSAID. Many people recognise the names, but fewer know what they actually do inside the body, or how different types of NSAIDs work.

Understanding the basics can help you use these medicines more safely and effectively, especially when you’re choosing between tablets, gels, sprays or patches.

In this guide, we explain how NSAIDs work, how topical versions differ, how long they take to work and whether it’s safe to mix them.

How do NSAIDs work?

NSAIDs are non-steroidal anti-inflammatory drugs. They are used to reduce pain, swelling and inflammation in a wide range of everyday conditions, from muscle strains and joint pain to headaches and dental pain.

When part of the body is injured or irritated, it releases substances called prostaglandins. These chemicals play a big role in causing pain, redness, heat and swelling. They are part of the body’s natural defence system, but they can also make injuries feel more painful and stiff than they need to be.

NSAIDs work by blocking enzymes known as cyclo-oxygenase enzymes (often shortened to COX enzymes). These enzymes are involved in making prostaglandins. When prostaglandin production is reduced, pain and inflammation usually ease.

That’s why NSAIDs can help with:

• Pain relief
• Reducing swelling
• Improving movement and stiffness.

However, prostaglandins don’t only cause pain. They also help protect the stomach lining, support kidney function and play a role in blood clotting. This is why NSAIDs can cause side effects in some people, particularly if taken at high doses or for long periods. It’s also why following the leaflet instructions really matters.

How do topical NSAIDs work?

Topical NSAIDs are applied directly to the skin, usually as a gel, cream, spray or patch. They contain the same type of medicine as some tablets, but the way they work in the body is slightly different.

Instead of travelling through the digestive system and bloodstream, a topical NSAID is absorbed through the skin and into the tissues underneath. The medicine then acts locally at the site of pain or inflammation.

This targeted approach means:

• The medicine is concentrated where it’s needed
• Lower amounts reach the rest of the body compared to tablets
• The risk of some whole-body side effects may be reduced.

This is why topical NSAIDs are often recommended as a first option for local muscle and joint pain, such as sprains, strains and minor sports injuries.

It’s worth noting that not all topical pain relief products are NSAIDs. Some Ralgex products, such as warming creams and sprays, work in a different way by creating a warming sensation on the skin. This can help relax tight muscles and increase comfort, but it doesn’t reduce inflammation in the same way as an NSAID.

Three important reminders regarding topical NSAIDs:

• They are still NSAIDs, so normal precautions apply
• They should only be used on unbroken, healthy skin
• Certain people should avoid using NSAIDs.

How long does it take for NSAIDs to kick in?

The time it takes for an NSAID to work depends on how it’s used and what type of pain you’re treating.

Oral NSAIDs, such as ibuprofen or diclofenac tablets, are absorbed into the bloodstream fairly quickly. Many people start to feel some relief within 20 to 30 minutes, although the full effect may take longer. This makes them useful for more general pain or when inflammation affects a wider area.

Topical NSAIDs usually take longer to show their full benefit. Because the medicine has to pass through the skin and build up in the tissues, improvement is often more gradual. For some people, relief begins within a day, but it can take several days of regular use to notice a clear difference, especially with ongoing joint pain.

This can feel frustrating if you’re expecting instant relief, but it’s normal. Topical NSAIDs are designed for steady, local treatment, not quick fixes.

Can you mix NSAIDs?

This is a common question, and the short answer is usually no.

Using more than one NSAID at the same time, such as taking ibuprofen tablets while also using a diclofenac gel, can increase the risk of side effects. These may include stomach irritation, indigestion, or more serious problems in people who are vulnerable.

It’s easy to accidentally mix NSAIDs without realising. For example:

• Taking ibuprofen for a headache while using an anti-inflammatory gel for a knee injury
• Using two different pain relief products that both contain NSAIDs.

Because topical products still contain an NSAID, they count towards your overall exposure. Even though less medicine enters the bloodstream, it’s still important to be cautious.

There are situations where a healthcare professional may say it’s appropriate, but this should be specific advice, not a guess. If you’re unsure, a pharmacist can quickly check what’s safe for you.

Paracetamol is often used alongside NSAIDs, as it works in a different way, but this isn’t suitable for everyone either. Always check the label and ask for advice if you’re uncertain.

Ralgex offers a range of pain relief options, so you can choose what best suits your type of pain. Our Ralgex® Pain Relief Cream contains a clinically proven warming ingredient, methyl salicylate, to increase blood flow to the affected area and ease discomfort and stiffness exactly where you need it to.

If you’re dealing with muscle or joint pain and want targeted relief, explore the Ralgex range and speak to a pharmacist if you need help choosing the right product for you.