Pharmaceutical giant GlaxoSmithKline Plc was the drug industry's top ad spender in 2006, relentlessly hawking its asthma and diabetes potions, but some important info did not make it into the company's campaigns. For instance, Glaxo knew its Avandia diabetes pill could cause heart and circulatory complications problems eight years ago when it won federal approval, but the concerns weren't really disseminated until late last month, when the Cleveland Clinic Foundation reported it has a 43% higher risk of heart attacks than other drugs. Glaxo had its own, similar data that Avandia raised the risk of heart attacks …