Abstract
We compared the effects of single doses of thioridazine and mesoridazine on the heart rate-corrected QT (QTc) interval in healthy adult volunteers. QTc intervals and plasma concentrations of thioridazine, mesoridazine, and metabolites were measured after single oral doses of thioridazine hydrochloride 50 mg, mesoridazine besylate 50 mg, or placebo in a double-blind, crossover study. Mean maximum increases in the QTc interval following thioridazine (37.3+/-4.1 ms, P=0.023) and mesoridazine (46.6+/-7.4 ms, P=0.021) were similar and significantly greater than following placebo (12.9+/-8.1 ms). The area under the effect-time curve over 8 h following drug administration was similar between the two drugs (129.3+/-22.1 vs 148.3+/-43.0 ms h). In conclusion, thioridazine and mesoridazine are associated with similar effects on the QTc interval.
Publication types
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Comparative Study
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Randomized Controlled Trial
MeSH terms
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Administration, Oral
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Adult
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Antipsychotic Agents / administration & dosage
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Antipsychotic Agents / adverse effects*
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Antipsychotic Agents / blood
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Antipsychotic Agents / pharmacokinetics
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Area Under Curve
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Cross-Over Studies
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Dopamine Antagonists / administration & dosage
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Dopamine Antagonists / adverse effects*
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Dopamine Antagonists / blood
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Dopamine Antagonists / pharmacokinetics
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Double-Blind Method
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Electrocardiography
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Female
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Heart Conduction System / drug effects*
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Humans
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Long QT Syndrome / chemically induced
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Long QT Syndrome / physiopathology
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Male
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Mesoridazine / administration & dosage
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Mesoridazine / adverse effects*
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Mesoridazine / blood
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Mesoridazine / pharmacokinetics
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Middle Aged
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Reference Values
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Thioridazine / administration & dosage
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Thioridazine / adverse effects*
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Thioridazine / blood
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Thioridazine / pharmacokinetics
Substances
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Antipsychotic Agents
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Dopamine Antagonists
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Mesoridazine
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Thioridazine