Everyone deals with physical pain at some point in life. No matter what kind of pain it is, it’s usually caused by inflammation. Inflammation, or swelling, happens when the body reacts to an injury, illness, or something that irritates it. Inflammation is often seen as a bad thing, but it’s actually part of the immune system’s way of protecting the body. A protein called cyclooxygenase (COX) plays an important role in protection by triggering inflammation. COX enzymes are essential parts of the chemical pathway that maintains the body’s ability for inflammation suppression.
This article explains some of the basics about COX: what it is, how it functions, and which medications can stop it from working.
What is cyclooxygenase, and how is it involved in inflammation?
Cyclooxygenase is a protein in the body that makes two chemicals: prostaglandin and thromboxane. These two chemicals are involved in the inflammatory response, which causes the blood vessels to widen, allowing more blood flow to the affected area. This increase in blood flow helps bring immune cells to start the healing process.
The body has two main types of COX enzymes: COX-1 and COX-2. COX-1 helps protect the body in many ways, while COX-2 mainly boosts inflammation. Certain drugs, like aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), target COX enzymes because they block their activity. This blocking effect helps reduce inflammation, fever, blood clots, and even some neurological and cancer-related issues. However, blocking COX-1 can also block some of its positive impacts, like the protection of the stomach lining.
The side effects of these drugs vary, depending mainly on whether they block COX-1 or COX-2. This is why stomach irritation could be one of the side effects of an NSAID medication.
In the past 40 years, scientists have learned much more about how COX enzymes work. This knowledge has led to the development of selective COX-2 inhibitors. These drugs were designed to reduce stomach problems caused by aspirin and other non-specific NSAIDs while still providing the same benefits.
What’s the difference between the two COX enzymes? 
COX-1
COX-1 is an enzyme that the body produces all the time. It doesn’t matter if someone is healthy, sick, or hurt, the body keeps making it regularly.
COX-1 plays an important role in the body by helping with several functions. It helps blood clot by making platelets stick together to stop bleeding. It also supports healthy blood flow in the kidneys and protects the lining of the stomach from damage.
COX-1 also helps produce thromboxane. There can be problems if there’s too much of this, such as heart attacks, strokes, and high blood pressure.
COX-2
COX-2 is an enzyme that the body makes more of when it has experienced some physical injury that provoked inflammation. There are also some conditions such as rheumatoid arthritis that can also cause elevated levels of COX2 to be produced.
Where are COX-1 and COX-2 found in the body?
COX-1 is found in many parts of the body, such as:
- Stomach lining
- Kidneys
- Uterus
- Platelets
- Heart and blood vessels
COX-2 is usually found in parts of the body where there is inflammation.
What medications block cyclooxygenase?
NSAID medications like ibuprofen (Advil, Nurofen) or naproxen (Naprosyn), and diclofenac (Cataflam) work by blocking COX enzymes. These are often used to treat common aches, pains, or fevers, and other less common conditions such as rheumatoid arthritis.
Specialized NSAIDs, such as celecoxib (Celebrex), are known as selective COX-2 inhibitors. They work by blocking the COX-2 enzyme more effectively than the COX-1 enzyme.
Aspirin works by blocking both COX-1 and COX-2, but it blocks COX-1 more. COX-1 helps platelets stick together, which can form blood clots that might lead to a heart attack or stroke. This makes aspirin a suitable treatment when blood thinning is required. People who’ve already had a heart attack or stroke might use aspirin to lower the chance of it happening again.
What are the side effects of blocking COX?
People taking NSAIDs should be aware of potential effects. Since not all NSAIDs block COX-1 and COX-2 the same way, the side effects can vary depending on the specific medication.
NSAIDs can affect the kidneys, especially in people who already have kidney problems. Prostaglandins, which help increase blood flow to the kidneys, play an essential role in keeping them working properly. Since both non-selective NSAIDs and COX-2 inhibitors block prostaglandin production, they can reduce kidney function. When the kidneys don’t work as they should, it can also lead to high blood pressure.
Side effects of blocking COX-1
Blocking COX-1 can cause stomach problems because COX-1 helps protect the gut lining. These problems can include an upset stomach, stomach bleeding, or even ulcers in the stomach, small intestine, or esophagus. Medications like non-selective NSAIDs and aspirin can cause these issues..
Side effects of blocking COX-2
Blocking COX-2 can lead to heart problems because it disrupts the body’s balance between prostaglandins and thromboxane. When COX-2 is heavily blocked, the body produces fewer prostaglandins, but thromboxane levels stay higher. Since high thromboxane can lead to blood clots, it increases the risk of heart attacks and strokes.
FAQs
Is Tylenol a COX inhibitor?
Paracetamol has been shown to inhibit COX-2, but it is not considered a selective COX inhibitor like Celebrex. Tylenol is commonly used to treat pain and fever, but it does not have the same anti-inflammatory effects as NSAIDs or COX-2 inhibitors.
How long can you take Celebrex for arthritis?
Celebrex should be taken exactly as directed by a doctor to ensure safe and effective use. Do not increase the dose, take it more often, or use it longer than prescribed, as this could increase the likelihood of side effects.
What is cyclooxygenase enzyme deficiency?
Cyclooxygenase deficiency, or COX deficit, is a rare genetic disorder caused by a lack of COX enzymes. It can cause various health issues, including changes to the inflammation responses and pain.
