Ziprasidone Benzatropine

In a randomized, Phase III, double-blind study, ziprasidone 80 mg/day and 160 mg was more effective than placebo in patients with acute exacerbations of schizophrenia or schizoaffective disorders (n = 302) (20). After 6 weeks, somnolence (19%) and akathisia (13%) were more frequent with ziprasidone 160 mg than with placebo (5 and 7% each). Benzatropine was required at some time during the study by 20% of the patients taking ziprasidone 80 mg/day, 25% of those taking ziprasidone 160 mg/day, and 13% of those taking placebo. The long-term safety of ziprasidone is unknown. 

The manufacturers warn of the possible risks of giving ziprasidone with drugs that prolong the QT interval, and of the possible antagonism that may occur with ievodopa and other dopamine agonists. Ziprasidone appears not to interact to a clinically relevant extent with an aiuminium/magnesium hydroxide antacid, benzatropine, cimetidine, iorazepam, propranolol or tobacco smoking. 

The manufaeturers say that population pharmaeokinetie analysis of schizophrenic patients who were enrolled in elinieal studies showed that no significant pharmacokinetic interactions occurred with benzatropine, Iorazepam or propranolol. The manufacturers also point out that since ziprasidone is not metabolised by the cytochrome P450 isoenzyme CYP1A2, smoking should not affect its pharmacokinetics. This is borne out by studies in patients, which did not reveal any differences in the pharmacokinetics of ziprasidone between tobacco smokers and non-smokers. ... 

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