of deaths in 2010 in the United States was verapamil. This agent is believed to cause more heart problems than many of the others. Diagnosis A blood or urine test to diagnose overdose is not generally available. CCB overdose may cause high blood sugar levels, and this is often a sign of how severe the problem will become. Electrocardiogram CCB toxicity can cause a number of electrocardiogram abnormalities with a low sinus rhythm being the most common. Others include: QT prolongation, bundle branch block, first-degree atrioventricular block, and even sinus tachycardia. Differential It may not be possible to tell the difference between beta blocker toxicity and calcium channel blocker overdose based on signs and symptoms. Management The medical management of CCB toxicity may be difficult. It may not improve with the usual treatments used for a low blood pressure and a slow heart rate. In those who have no symptoms or signs six hours following taking an immediate release formulation and 24 hours after taking an extended release formulation need no further medical treatment. Detoxification Activated charcoal is recommended if it can be given within an hour or two of taking the calcium channel blockers. In those who have taken an extended release formulation of a CCB but are otherwise doing fine, whole bowel irrigation with polyethylene glycol may be useful. Causing vomiting by the use of medications such as ipecac is not recommended. Insulin High doses of intravenous insulin with glucose may be useful and are a first line treatment in overdoses. As this treatment may cause a drop in blood sugar and blood potassium levels, these should be monitored closely. Other Intravenous calcium gluconate or calcium chloride is considered a specific antidotes. Slow heart rate can be treated with atropine and sympathomimetics. Low blood pressure is treated with vasopressors such as adrenaline. There is tentative clinical evidence and good theoretical evidence of the benefit of lipid emulsion in severe overdoses of CCBs. Methylene blue may also be used for those with low blood pressure that does not respond to other treatments. Epidemiology More than 10,000 cases of potential calcium channel blocker toxicity occurred in the United States in 2010. When death occurs in medicine overdose, heart medications are the cause more than 10% of time. The three most common types of heart medications that result in this outcome are calcium channel blockers along with beta blockers and digoxin.