Haloperidol arrhythmia with

Hypersensitivity to the drug or any other component of the product (cross-sensitivity between phenothiazines may occur) comatose or greatly depressed states caused by CNS depressants or from any other cause (phenothiazines, clozapine, loxapine, molindone, pimozide, haloperidol) coadministration with other drugs that prolong the QT interval and in patients with congenital long QT syndrome or history of cardiac arrhythmias (mesoridazine, thioridazine, pimozide, ziprasidone see Drug..Interactions). 

Haloperidol is less likely to cause hypotension than chlorpromazine, which has a-adrenoceptor antagonist effects. Both can cause cardiac arrhythmias if used in high dosage or in patients with pre-existing heart disease, or as an idiosyncratic reaction. There have been numerous reports of sudden and unexplained deaths, probably due to cardiac arrhythmia, in patients given chlorpromazine and other neuroleptics. The risk of serious arrhythmia is higher in the obese, and possibly in those of African ancestry. 

Metzger E, Friedman R Prolongation of the corrected QT and torsades de pointes cardiac arrhythmia associated with intravenous haloperidol in the medically ill. J Clin Psychopharmacol 13 128—132, 1993... 

Frequent symptoms of amphetamine withdrawal include excessive fatigue and depression. These may also occur nausea, vomiting, chills, cramps, headaches, and arrhythmia (a change in the rhythm of the heartbeat). A physician may prescribe antidepressants to help alleviate depression during amphetamine withdrawal. Also during withdrawal, if psychosis and/or hallucinations are experienced, treatment with chlorpromazine (Thorazine) or haloperidol (Haldol) may be necessary. Finally, ammonium chloride may be prescribed to more quickly remove amphetamines through the urine. 

Overdose is common amongst users (up to 22% of heavy users report losing consciousness). The desired euphoria and excitement turns to acute fear, with psychotic symptoms, convulsions, hypertension, haemorrhagic storke, tachycardia, arrhythmias, hyperthermia coronary vasospasm (sufficient to present as the acute coronary syndrome with chest pain and myocardial infarction) may occur, and acute left ventricular dysfunction. Treatment is chosen according to the clinical picture (and the known mode of action), from amongst, e.g. haloperidol (rather than chlorpromazine) for mental disturbance diazepam for convulsions a vasodilator, e.g. a calcium channel blocker, for hypertension glyceryl trinitrate for myocardial ischaemia (but not a p-... 

Pimozide is available as an antipsychotic limited to use as an alternate to haloperidol in the treatment of Tourette s syndrome (TS). It is indicated for patients with severe symptoms who cannot tolerate or do not respond to haloperidol. The adverse reaction profile is similar to that of other neuroleptics however, serious ventricular arrhythmias can occur sudden unexpected deaths have been reported with high doses. 

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