<p>Celebrex is part of a class of drugs known as non-steroidal anti-inflammatory drugs and is similar to ibuprofen and naproxen. The drugs are associated with an increased risk of heart tacks and stroke. In 2004, a drug from the same class, Vioxx, was pulled from the market because of these potential side effects.<br /><br />As of 2005 non-steroidal anti-inflammatory drugs were required to carry the strongest black box warning about the drugs' possible risks. <br /><br />The new advert will highlight the fact that ibuprofen and naproxen carry similar warnings about cardiovascular risk but will stress that Celebrex has never been taken off the market.<br /><br />Pfizer decided to bring back the Celebrex ads after its research found that 40% of consumers believed that the drug was no longer available.</p>