COX 2 (Cyclo-Oxygenase) Inhibitors

27th November 2006 at 13:09 GMT by Dr.C.A.Jenner MB BS, FRCA. Permalink.

Article on the pharmacological properties and adverse effects of COX 2 (Cyclo-Oxygenase) Inhibitors

Introduction

The cyclo-oxygenase 2 (COX-2) inhibitors are a new form of non-steroidal anti-inflammatory drugs (NSAIDs) that are considered to produce fewer gastro-intestinal side effects than the older non-selective drugs.

Successive data raised substantive concerns of an increased risk of cardiovascular events, such as heart attacks and strokes and a risk for the occurrence of serious skin reactions for this class of medicines.

COX-2 inhibitor drugs include

• Celebrex (Celecoxib)
• Bextra (Valdecoxib)
• Arcoxia (Etoricoxib)

Uses of COX-2 inhibitors

FDA Regulations

In a significant development, the Food and Drug Administration (FDA) recently released important statements and directions regarding the marketing and sale of COX-2 inhibitors.

As informed in the FDA press release (February 2005), the FDA directed Pfizer, Inc. to withdraw Bextra (valdexocib) from the market because the overall potential risks outweigh the benefits of the drug.

The FDA also directed Pfizer, Inc. to include a boxed warning in the Celebrex (celecoxib) label. As a result, Pfizer, Inc. agreed to suspend sales and marketing of Bextra in the US and work with FDA on the boxed warning for Celebrex.

In addition, the FDA also issued supplemental request letters to sponsors of all COX-2 inhibitors to revise the labeling (packaging insert) for their products. The revised labeling is required to include a boxed warning highlighting the potential for increased risk of cardiovascular events and life-threatening gastrointestinal bleeding associated with their use.

Advice for patients

In light of the various research findings on the side effects of COX-2 inhibitors, patients are advised as below:

• Patients taking COX-2 inhibitors presently and having a history of a stroke, mini-stroke, coronary heart disease or peripheral arterial disease should review the prescription with their health care provider.
• Patients are also advised that though stopping COX-2 inhibitors will not cause any harm, yet they are likely to need alternative treatment to control symptoms.
• Patients who exhibit risk factors for heart disease or stroke should review the possible overall cardiovascular risks and risks of suffering gastrointestinal problems.
• Aged patients and those taking this medication for longer periods of time are at a greater risk and hence should review their prescription with the healthcare provider.

Other reports

According to a report released in June 2005, the European Medicines Agency (EMEA) recommended the suspension of the marketing authorization of Bextra (valdecoxib). EMEA also recommended new warnings and contraindications for other COX-2 inhibitors that continued to be available in the European Union (EU).