Coxibs (also known as COX-2 inhibitors) are a type of non-steroidal anti-inflammatory drug (NSAID). Coxibs, like other NSAIDs, relieve pain and reduce inflammation.
They are sometimes also known as ‘selective NSAIDs’ because they act only on the COX-2 enzyme, rather than both COX-1 and COX-2 like the non-selective NSAIDs such as ibuprofen and diclofenac. The coxibs were developed to reduce the risk of gastrointestinal side effects associated with non-selective NSAIDs.
What conditions are treated with coxibs?
Some people will feel a benefit within a few hours of taking a dose, but if the coxib does not relieve your pain after you have taken it for 2 weeks, tell your doctor – they may suggest trying a different pain killer.
How do COX-2 inhibitors work?
COX enzymes are produced in the body and help to make chemicals called prostaglandins, which are produced in response to injury or infection as part of the body’s natural healing process. Prostaglandins are involved in inflammation, which then promotes pain.
NSAIDs work by blocking COX enzymes in the body and interrupt the production of prostaglandins. Both COX enzymes produce prostaglandins, but:
- COX-1 is useful to the body and protects the lining of the stomach and your gastrointestinal tract
- COX-2 is the enzyme mainly responsible for making the prostaglandins involved in pain and inflammation in diseases such as arthritis
Non-selective NSAIDs – block both COX-1 and COX-2 enzymes. This means that even though they block the inflammatory effect of COX-2, they also block the beneficial effects of COX-1, and so increase the risk of stomach upsets and stomach ulcers.
Coxibs – block mainly the COX-2 enzyme, while sparing the protective COX-1 enzyme. However, they are still associated with adverse gastrointestinal effects, according to the Australian Medicines Handbook, but the risk is generally lower than with non-selective NSAIDs.
Coxibs in Australia
There are a few types of COX-2 inhibitors available in Australia.
|Coxib medicines in Australia|
|Generic name||Brand names|
|celecoxib||APO-Celecoxib, Blooms the Chemist Celecoxib, Celaxib, Celebrex, Celecoxib BTC, Celecoxib GH, Celecoxib RBX, Celecoxib Sandoz, Celexi, Chemmart Celecoxib Capsules, GenRx Celecoxib Capsules, Terry White Chemists Celecoxib Capsules|
|meloxicam||APO-Meloxicam, Chemmart Meloxicam Capsules, Chemmart Meloxicam Tablets, Cipla Meloxicam Tablets, Clonac Tablets, Melobic Capsules, Melox Capsules, Meloxiauro Tablets, Meloxibell Tablets, Meloxibindo Tablets, Meloxicam AN Tablets, Meloxicam Ranbaxy Tablets, Meloxicam Sandoz, Mobic, Movalis, Moxicam, Pharmacor Meloxicam, Terry White Chemists Meloxicam|
Are coxibs safe?
Both the coxibs and the non-selective NSAIDs increase the risk of cardiovascular events, such as heart attack and stroke. This risk increases the higher the dose taken and the longer the duration of treatment. For this reason it’s recommended to take the lowest dose that relieves symptoms, for the shortest period of time. (See below for who should not take coxibs).
An earlier coxib called rofecoxib (brand name Vioxx) was withdrawn worldwide as people taking the drug long term had double the risk of heart attack compared with people on placebo (dummy) treatment.
In terms of gastrointestinal and stomach complications (such as stomach irritation or ulcers) the coxibs generally have a lower risk than the non-selective NSAIDs.
You can discuss the risks and benefits of treatment with coxibs with your doctor or pharmacist, who will be able to tell you whether or not they are suitable for you.
Who should not take coxibs?
People at higher risk of heart or blood vessel disease should not take coxibs, unless on the advice of their doctor. This includes anyone with coronary heart disease (including angina), peripheral vascular disease, heart failure or narrowed arteries to the brain. Your doctor will be able to tell you whether or not coxibs are suitable for you.
People who are allergic to sulfonamides (e.g. sulfamethoxazole) should avoid celecoxib, and people who have had severe asthma or an allergic reaction to NSAIDs should not take a coxib.
Coxibs should not be taken in addition to other NSAIDs.
Don’t take NSAIDs if you are dehydrated, as this may increase the risk of side effects. It’s important that your doctor knows your full medical history before prescribing coxibs, including whether you have liver or kidney problems.
Coxibs, like most NSAIDs, may not be suitable in pregnancy or when breastfeeding.
Side effects of coxibs
The potential side effects of coxibs include indigestion, stomach upset, nausea, stomach ulcer, perforated ulcer, high blood pressure, dizziness and kidney effects. Drinking too much alcohol increases the risk of stomach ulcers when taking NSAIDs. Always tell your doctor if you develop side effects when taking a medicine.
Are coxibs available over the counter?
In Australia, coxibs are available on prescription only.