Question

Richard is a 55 year old man who has been diagnosed with rheumatoid arthritis. Before being diagnosed, he was taking OTC ibuprofen to manage his pain. Once diagnosed, his prescriptions included celecoxib. He was also advised to stop taking additional OTC ibuprofen.

1. Explain the mechanism of action and clinical effects of each of the drugs Richard has been taking.

2. Compare and contrast the mechanism of action ibuprofen and celecoxib. Why might Richard have been prescribed celecoxib? Why do you think he was advised not to take additional ibuprofen?

Answer 1

Ibuprofen is non selective COX inhibitor. It is a class of non steroidal anti inflammatory drugs(NSAIDs).

Ibuprofen is a propionic acid derivative.

In condition like rheumatoid arthritis, there is increased production of prostaglandin, prostacyclin and thromboxane A2. All these are produced from arachidonic acid by the activity of enzyme cyclooxygenase which exist in COX-1 and COX-2 form.

Elevation of these prostaglandins results in typical pain of arthritis.

NSAIDs (Ibuprofen and Celecoxib) inhibits these COX enzymes and thus relieve pain .

Ibuprofen is a non selective COX inhibitor. It inhibits both COX-1 and COX -2 .

On the other hand, Celecoxib is a selective COX-2 inhibitor.

The advantage of using selective COX-2 inhibitor is that the side effects are less. With Ibuprofen, chances of stomach ache and ulcers are high.

But by just inhibiting only COX-2 inhibitor, we the side effects are less. Also, Celecoxib is more potent that Ibuprofen in relieving pain.

Also, using using Ibuprofen and Celecoxib together will increase chance of gastrointestinal toxicity.