Precautions and Warnings With Haloperidol (Cont.)

• There have been reports of sudden death in people taking haloperidol, most likely due to a dangerous irregular heart rhythm (arrhythmia) called QT prolongation. This problem is more likely in people with low potassium levels in the blood (hypokalemia) or other electrolyte imbalances. It is also more likely in people with long QT syndrome (who are prone to QT prolongation arrhythmias).

• Haloperidol can cause a life-threatening condition called neuroleptic malignant syndrome (NMS). Some symptoms of NMS include:

• A high fever
• Stiff muscles
• Confusion
• An irregular pulse or blood pressure
• A fast heart rate (tachycardia)
• Sweating
• An irregular heart rhythm (arrhythmia).

Tell your healthcare provider right away if think you might have NMS.

• Haloperidol can cause tardive dyskinesia, a condition involving unusual, uncontrollable body or face movements. The condition can become permanent (even if haloperidol is stopped). The best way to prevent it from becoming permanent is to tell your healthcare provider right away if you notice any abnormal movements (including abnormal movements of the tongue) while taking haloperidol.
   
• There have been cases of pneumonia (some of which proved fatal), possibly due to haloperidol. If you have symptoms of pneumonia -- such as a cough, chest pain, and a fever -- let your healthcare provider know right away.
   
• Haloperidol can impair your mental or physical abilities to drive a car or operate heavy machinery. Make sure that you know how haloperidol affects you before you do any activities that require mental concentration or physical coordination.
   
• Haloperidol can cause a drop in blood pressure (hypotension). This can cause a person to have lightheadedness or dizziness, or to faint. Tell your healthcare provider if you have any of these symptoms when standing. Hypotension can be especially dangerous in people with heart disease or congestive heart failure (CHF). Combining alcohol with haloperidol can also increase the risk of hypotension (see Alcohol and Haldol).
   
• Haloperidol may increase the risk of seizures. Before starting haloperidol, tell your healthcare provider if you have epilepsy or a history of seizures.
   
• Haloperidol can cause a "switch" to depression in people with bipolar disorder.
   
• Haloperidol can cause dangerous side effects in people with an uncontrolled, overactive thyroid (hyperthyroidism). If you have thyroid problems, be sure to talk with your healthcare provider before taking haloperidol.
   
• Haloperidol is considered a pregnancy Category C medication. This means that it may not be safe to take during pregnancy. Be sure to talk with your healthcare provider about the risks and benefits of using haloperidol during pregnancy (see Haldol and Pregnancy).
   
• Haloperidol passes through breast milk. Therefore, if you are breastfeeding or plan to start breastfeeding, be sure to talk with your healthcare provider about using haloperidol (see Haldol and Breastfeeding for more information).
   
• Haloperidol can interact with certain other medications (see Drug Interactions With Haloperidol).