Posicor was the trade name for the prescription drug Mibefradil, which was developed and produced by Roche Laboratories from 1997 to 1998. The drug was a calcium channel blocker, prescribed as treatment for chronic stable angina pectoris and hypertension, helping to decrease blood pressure without lessening heart contractions. In June 1998 Roche withdrew the drug from the market voluntarily, citing potentially life-threatening interactions when taken with other medications, namely agents metabolized by P450. A number of deaths have since been attributed to the use of the drug. Other, non life-threatening side effects of Posicor included headaches, nausea, abdominal pain, fatigue and nasal congestion. Almost 200,000 Americans were believed to be taking Posicor before the recall.