Last week the watchdog group, Public Citizen petitioned the FDA to add it's "strongest possible warning label" to the labels for PPIs (Proton-Pump Inihbitor medications). This class of drugs includes such well-known drugs as Nexium, Prilosec, Zegerid and Prevacid.
Public Citizen says the risk of so called "rebound acid hypersecretion" for individuals who take these drugs on a regular basis for a month or so and then stop is a major problem with these drugs. Basically, people who suffer from this condition end up with more serious acid reflux symptoms than they had prior to taking the drugs, so they begin taking them again starting a vicious cycle of long-term dependence.
Other risks noted in the petition to the FDA included severese magnesium deficiencies and fractures of the hip, wrist and spine. Some studies have also shown that this class of drugs may reduce the effectiveness of certain heart drugs when they are taken together.