First generation antipsychotics with an increased risk of QTc prolonging include tioridazina (the highest risk), pimozide, droperidole, mesoridazine
and haloperidole with intravenous administration (total cumulative dose > 2 mg) and from the second generation sertindole, amisulpride and ziprasidone.
As melperone, mesoridazine
, and pimozide are the three drugs missing additional muscarinic, adrenergic, histaminic and even [D.sub.1] action,  the comparison of serotonin versus [D.sub.2/4] action is easier.
The distribution of typical and atypical antipsychotic exposures Antipsychotics n % Typical antipsychotics Thioridazine 4 6.1 Chlorpromazine 5 7.6 Mesoridazine
1 1.5 Trifluoperazine 3 4.5 Zuclopenthixol 1 1.5 Haloperidol 1 1.5 Total 15 22.7 Atypical antipsychotics Quetiapine 27 40.9 Risperidone 15 22.8 Olanzapine 8 12.1 Clozapine 1 1.5 Total 51 77.3 Total 66 100.0 Table 3.
Sertindole was never marketed in the US ; mesoridazine
was marketed in the US but with a warning regarding dose-related QTc prolongation and associated risk of torsade de pointes .
Second, we excluded drugs that were unavailable in Taiwan, including pentazocine, trimethobenzamide, amphetamines, guanadrel, mesoridazine
, mineral oil, and desiccated thyroid.
Specifically, concerns center around the piperidine phenothiazines (thioridazine and mesoridazine
) because of the increased risk of electrocardiographic changes and medication-induced arrhythmias in renal disease due to electrolyte imbalances.
A low-risk drug was prescribed to the rest of the patients (aripiprazole, ziprasidone, haloperidol, fluphenazine, molindone, pimozide, or mesoridazine
Electrocardiographic evaluation of mesoridazine
. Curr Ther Res 1974; 14: 71.
Some of the psychotropic drugs that can possibly cause TdP are listed in Table 5 and include chlorpromazine, haloperidol, pimozide, thioridazine, mesoridazine
, and ziprasidone.
Antipsychotic Medications, Generic and Brand Names and Typical Tablet Dosage Generic Name Brand Name Tablet dosage range Atypical Risperidone Risperdal 1-3 mg Olanzapine Zyprexa 2.5-10 mg Clozapine Clozaril 25-100 mg Quetiapine Seroquel 25-200 mg Ziprasidone Geodon 20-60 mg Aripiprazole Abilify 5-15 mg High Potency Haloperidol Haldol 0.5-20 mg Typical Pimozide Orap 2 mg Fluphenazine Prolixin 2.5-10 mg Medium Potency Trifluoperazine Stelazine 1-10 mg Typical Perphenazine Trilafon 2-16 mg Thiothixene Navane 2-20 mg Loxapine Loxitane 5-50 mg Low Potency Molindone Moban 5-100 mg Typical Mesoridazine
Serentil 10-100 mg Thioridazine Mellaril 10-200 mg Chlorpromazine Thorazine 10-200 mg Adapted from Wilens (1999) and Li, Pearrow, & Jimerson (2010).
Furthermore, several drugs may produce false positive results for phencyclidine including ketamine, dextromethorphan, diphenhydramine, ibuprofen, imipramine, meperidine, mesoridazine
, thioridazine, and venlafaxine (Sena, Kazimi & Wu 2002).
Currently available drugs associated with QT prolongation include most anti-dysthythmics, erythromycin, droperidol, mesoridazine
, and methadone.