A Phase 2 clinical trial of PF-05212377 (SAM-760) in subjects with mild to moderate Alzheimer's disease with existing neuropsychiatric symptoms on a stable daily dose of donepezil.

BACKGROUND: Symptomatic benefits have been reported for 5-HT6 receptor antagonists in Alzheimer's disease (AD) trials. SAM-760 is a potent and selective 5-HT6 receptor antagonist that has demonstrated central 5-HT6 receptor saturation in humans at a dose of 30 mg. METHODS: This was a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial evaluating the efficacy and safety of SAM-760 30 mg once daily (QD) for 12 weeks in subjects with AD on a stable regimen of donepezil 5 to 10 mg QD. The study included an interim analysis with stopping rules for futility or efficacy after 180 subjects completed the week 12 visit. Up to 342 subjects with AD (Mini-Mental State Examination (MMSE) score 10-24) and neuropsychiatric symptoms (Neuropsychiatric Inventory (NPI) total score ≥ 10) were to be enrolled if the study continued after the interim analysis. After a 4-week, single-blind, placebo run-in period, subjects entered the 12-week double-blind period and were randomized to either SAM-760 or placebo. The primary and key secondary efficacy endpoints were the change from baseline in Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog13) and NPI total scores. Mixed models for repeated measures were used to analyze the data. RESULTS: At the interim analysis, when 186 subjects had been randomized and 163 had completed the week 12 visit, the study met futility criteria and was stopped. The mean week 12 treatment difference was 0.70 points (P = 0.43) for ADAS-cog13 and 2.19 points (P = 0.20) for NPI score, both of which were numerically in favor of placebo. Other secondary endpoints did not demonstrate any significant benefit for SAM-760. In total, 46.2% of SAM-760 subjects reported adverse events (AE) versus 44.7% for placebo, and there were 5 (5.5%) serious AEs in the SAM-760 group versus 3 (3.2%) for placebo. There were two deaths, one prior to randomization and one in the SAM-760 group (due to a traffic accident during washout of active treatment). CONCLUSIONS: SAM-760 was safe and well tolerated, but there was no benefit of SAM-760 on measures of cognition, neuropsychiatric symptoms, or daily function. Differences in trial design, study population, region, or pharmacological profile may explain differences in outcome compared with other 5-HT6 receptor antagonists. TRIAL REGISTRATION: Clinicaltrials.gov, NCT01712074 . Registered 19 October 2012.

Pregabalin versus pramipexole: effects on sleep disturbance in restless legs syndrome.

STUDY OBJECTIVES: To compare pregabalin versus placebo and pramipexole for reducing restless legs syndrome (RLS)-related sleep disturbance. DESIGN: Randomized, double-blinded, crossover trial. SETTING: Twenty-three US sleep centers. PARTICIPANTS: Eighty-five individuals with moderate to severe idiopathic RLS and associated sleep disturbance. INTERVENTIONS: Participants were randomized across 6 treatment sequences comprising three 4-week periods on pregabalin 300 mg/day (n = 75), pramipexole 0.5 mg/day (n = 76), or placebo (n = 73). MEASUREMENTS AND RESULTS: Polysomnography was conducted over 2 nights at the end of each period. Primary (wake after sleep onset [WASO], pregabalin vs placebo) and key secondary endpoints were analyzed for statistical significance, with descriptive statistics for other endpoints. Pregabalin improved sleep maintenance, demonstrated by reductions in WASO (-27.1 min vs placebo [P < 0.0001]; -26.9 vs pramipexole) and number of awakenings after sleep onset (-2.7 vs placebo; -7.9 vs pramipexole [P < 0.0001]) by polysomnography, and an increase in subjective total sleep time (30.8 min vs placebo [P < 0.0001]; 26.8 vs pramipexole). Pregabalin also increased slow wave sleep duration (20.9 min vs placebo; 32.1 vs pramipexole [P < 0.0001]). Reduction in periodic limb movement arousal index (PLMAI) with pregabalin was similar to pramipexole and greater than placebo (-3.7 PLMA/h [P < 0.0001]), although reduction in total PLM in sleep was less than for pramipexole. CONCLUSIONS: This study demonstrated improvements in objective and subjective measures of sleep maintenance and sleep architecture with pregabalin compared with placebo and pramipexole. Effects of pregabalin on periodic limb movement arousal index were comparable to pramipexole. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT00991276; http://clinicaltrials.gov/show/NCT00991276.

Comparison of pregabalin with pramipexole for restless legs syndrome.

BACKGROUND: Dopaminergic medications relieve symptoms of the restless legs syndrome (RLS) but have the potential to cause iatrogenic worsening (augmentation) of RLS with long-term treatment. Pregabalin may be an effective alternative. METHODS: In this 52-week, randomized, double-blind trial, we assessed efficacy and augmentation in patients with RLS who were treated with pregabalin as compared with placebo and pramipexole. Patients were randomly assigned to receive 52 weeks of treatment with pregabalin at a dose of 300 mg per day or pramipexole at a dose of 0.25 mg or 0.5 mg per day or 12 weeks of placebo followed by 40 weeks of randomly assigned active treatment. The primary analyses involved a comparison of pregabalin and placebo over a period of 12 weeks with use of the International RLS (IRLS) Study Group Rating Scale (on which the score ranges from 0 to 40, with a higher score indicating more severe symptoms), the Clinical Global Impression of Improvement scale (which was used to assess the proportion of patients with symptoms that were "very much improved" or "much improved"), and a comparison of rates of augmentation with pregabalin and pramipexole over a period of 40 or 52 weeks of treatment. RESULTS: A total of 719 participants received daily treatment, 182 with 300 mg of pregabalin, 178 with 0.25 mg of pramipexole, 180 with 0.5 mg of pramipexole, and 179 with placebo. Over a period of 12 weeks, the improvement (reduction) in mean scores on the IRLS scale was greater, by 4.5 points, among participants receiving pregabalin than among those receiving placebo (P<0.001), and the proportion of patients with symptoms that were very much improved or much improved was also greater with pregabalin than with placebo (71.4% vs. 46.8%, P<0.001). The rate of augmentation over a period of 40 or 52 weeks was significantly lower with pregabalin than with pramipexole at a dose of 0.5 mg (2.1% vs. 7.7%, P=0.001) but not at a dose of 0.25 mg (2.1% vs. 5.3%, P=0.08). There were six cases of suicidal ideation in the group receiving pregabalin, three in the group receiving 0.25 mg of pramipexole, and two in the group receiving 0.5 mg of pramipexole. CONCLUSIONS: Pregabalin provided significantly improved treatment outcomes as compared with placebo, and augmentation rates were significantly lower with pregabalin than with 0.5 mg of pramipexole. (Funded by Pfizer; ClinicalTrials.gov number, NCT00806026.).

Ziprasidone and the corrected QT interval: a comprehensive summary of clinical data.

BACKGROUND: Prolongation of the corrected QT interval (QTc) is understood to be a predictor of risk for ventricular arrhythmia; consequently, data on QTc effects of drugs are used by regulatory bodies to evaluate potential safety risks. Clinical pharmacology studies in adults receiving oral ziprasidone demonstrated a dose-dependent mean increase (4.5-19.5 milliseconds [ms]) in QTc over the range of 40-160 mg/d with a small incremental increase (22.5 ms) at 320 mg/d. In a comparative study of ziprasidone versus five antipsychotics, the mean QTc increase at steady state maximum concentration (C(max)) for ziprasidone was 15.9 ms. Accordingly, the effects of ziprasidone on QTc were studied in phase II-IV randomized controlled trials (RCTs). OBJECTIVE: The objective of this study was to provide clinicians and clinical researchers with a comprehensive analysis of QTc changes associated with ziprasidone based on data from Pfizer-sponsored phase II-IV RCTs in schizophrenia or bipolar disorder patients, safety reports and post-marketing surveillance. METHODS: The following analyses of data were conducted to obtain a comprehensive summary of QTc data on ziprasidone: (i) post hoc analyses (using primarily descriptive statistics) of pooled QTc data (Fridericia correction) from more than 40 phase II-IV adult ziprasidone RCTs organized according to the following subgroups: all monotherapy studies in schizophrenia and bipolar disorder, all intramuscular (IM) studies, adjunctive studies in bipolar disorder and fixed-dose oral studies; (ii) post hoc analyses from 36 phase II-IV adult ziprasidone RCTs exploring the relationship between QTc change from baseline and baseline QTc in adults; (iii) post hoc analyses from phase II-IV adult ziprasidone RCTs modelling QTc change as a function of ziprasidone concentration in both adult (17 studies) and paediatric (5 studies) subjects; (iv) cardiac adverse event (AE) reports from all phase II-IV adult ziprasidone RCTs in schizophrenia; (v) a large simple trial entitled Ziprasidone Observational Study of Cardiac Outcomes (ZODIAC) in 18 154 subjects with schizophrenia (the only previously reported results included here); and (vi) cardiac-related AEs presented in a ziprasidone post-marketing surveillance report created in 2007. RESULTS: A total of 4306 adults received ziprasidone in placebo- and active-comparator phase II-IV RCTs and had evaluable QTc data. One subject reached a QTc ≥480 ms; 33 (0.8%) had a QTc ≥450 ms. QTc prolongation ≥30 ms was observed in 389 subjects (9.0%); ≥60 ms in 30 (0.7%); and ≥75 ms in 12 (0.3%). In the placebo-controlled studies, mean change in QTc from baseline to end of study was 3.6 (± 20.8) ms in the ziprasidone group; the corresponding QTc change in the pooled placebo group was -0.3 (± 20.6) ms. Data from IM studies, and bipolar studies in which ziprasidone was used adjunctively with lithium, valproate or lamotrigine, demonstrated similar QTc effects. A scatter-plot of QTc prolongation against baseline QTc showed QTc prolongation ≥60 ms exclusively in adult subjects with a baseline QTc ≤400 ms. The final concentration-response analysis model, comprising 2966 data points from 1040 subjects, estimates an increase in QTc of 6 ms for each 100 ng/mL increase in ziprasidone concentration. The large simple trial (ZODIAC) failed to show that ziprasidone is associated with an elevated risk of non-suicidal mortality relative to olanzapine in real-world use. Post-marketing data over a 5-year period did not show a signal of increased cardiac AEs. CONCLUSIONS: These analyses provide the first comprehensive summary of QTc changes associated with ziprasidone based on Pfizer-sponsored phase II-IV RCTs, safety reports and post-marketing surveillance. The results of the analyses of pooled data from phase II-IV RCTs in adults demonstrate a modest mean increase in QTc, infrequent QTc prolongation ≥60 ms (<1.0%) and rare observation of QTc ≥480 ms. These data are consistent with results from ziprasidone clinical pharmacology studies, safety reports and post-marketing surveillance. Taken together, they provide the most comprehensive evidence published to date that ziprasidone appears to be safe when used as indicated in patients with schizophrenia or bipolar disorder.

Adjunctive therapy with pregabalin in generalized anxiety disorder patients with partial response to SSRI or SNRI treatment.

This study evaluated the efficacy of adjunctive pregabalin versus placebo for treatment of patients with generalized anxiety disorder (GAD) who had not optimally responded to previous or prospective monotherapies. This was a phase 3, randomized, double-blind, placebo-controlled study. Patients diagnosed with GAD who had a historical and current lack of response to pharmacotherapy [Hamilton Anxiety Rating Scale (HAM-A) of ≥ 22 at screening] were randomized to adjunctive treatment with either pregabalin (150-600 mg/day) or placebo. The primary outcome measure was the change in HAM-A total scores after 8 weeks of combination treatment. Adverse events were regularly monitored. Randomized patients (N=356) were treated with pregabalin (n=180) or placebo (n=176). Mean baseline HAM-A scores were 20.7 and 21.4, respectively. After treatment, the mean change in HAM-A was significantly greater for pregabalin compared with placebo (-7.6 vs. -6.4, respectively; P<0.05). HAM-A responder rates (≥ 50% reduction) were significantly higher for pregabalin (47.5%) versus placebo (35.2%; P=0.0145). The time-to-sustained response favored pregabalin over placebo (P=0.014). Adverse events were consistent with previous studies and discontinuations were infrequent for pregabalin (4.4%) and placebo (2.3%). The study was discontinued early after an interim analysis. The results indicate that adjunctive pregabalin is an efficacious therapy for patients with GAD who experience an inadequate response to established treatments.

A randomized, double-blind, 6-week, dose-ranging study of pregabalin in patients with restless legs syndrome.

OBJECTIVE: This study evaluated the dose-related efficacy and safety of pregabalin in patients with idiopathic restless legs syndrome (RLS). METHODS: This six-arm, double-blind, placebo-controlled, dose-response study randomized patients (N=137) with moderate-to-severe idiopathic RLS in an equal ratio to placebo or pregabalin 50, 100, 150, 300, or 450 mg/day. The dose-response was characterized using an exponential decay model, which estimates the maximal effect (E(max)) for the primary endpoint, the change in the International Restless Legs Study Group Rating Scale (IRLS) total score from baseline to week 6 of treatment. Secondary outcomes included Clinical Global Impressions-Improvement Scale (CGI-I) responders, sleep assessments, and safety. RESULTS: The separation of treatment effect between placebo and pregabalin began to emerge starting at week 1 which continued and increased through week 6 for all dose groups. The IRLS total score for pregabalin was dose dependent and well characterized for change from baseline at week 6. The model estimated 50% (ED(50)) and 90% (ED(90)) of the maximal effect in reducing RLS symptoms that occurred at pregabalin doses of 37.3 and 123.9 mg/day, respectively. A higher proportion of CGI-I responders was observed at the two highest doses of pregabalin (300 and 450 mg/day) versus placebo. Dizziness and somnolence were the most common adverse events and appeared to be dose-related. CONCLUSIONS: In this 6-week phase 2b study, pregabalin reduced RLS symptoms in patients with moderate-to-severe idiopathic RLS. The symptom reduction at week 6 was dose-dependent with 123.9 mg/day providing 90% efficacy. Pregabalin was safe and well tolerated across the entire dosing range.

Effects of high-dose ziprasidone and haloperidol on the QTc interval after intramuscular administration: a randomized, single-blind, parallel-group study in patients with schizophrenia or schizoaffective disorder.

BACKGROUND: Antipsychotic agents have been associated with a prolonged QT interval. Data on the effects of ziprasidone and haloperidol on the QTc interval are lacking. OBJECTIVE: This study aimed to characterize the effects of 2 high-dose intramuscular injections of ziprasidone and haloperidol on the QTc interval at T(max). METHODS: This randomized, single-blind study enrolled patients with schizophrenia or schizoaffective disorder in whom long-term antipsychotic therapy was indicated. Patients were randomized to receive 2 high-dose intramuscular injections of ziprasidone (20 and 30 mg) or haloperidol (7.5 and 10 mg) separated by 4 hours. The primary outcome measure was the mean change from baseline in QTc at the T(max) of each injection. Each dose administration was followed by serial ECG and blood sampling for pharmacokinetic determinations. Twelve-lead ECG data were obtained immediately before and at predetermined times after injections. ECG tracings were read by a blinded central reader. Blood samples were obtained immediately before and after injections. Point estimates and 95% CIs for mean QTc and changes from baseline in QTc were estimated. No between-group hypothesis tests were conducted. For the assessments of tolerability and safety profile, patients underwent physical examination, including measurement of vital signs, clinical laboratory evaluation, and monitoring for adverse events (AEs) using spontaneous reporting. RESULTS: A total of 59 patients were assigned to treatment, and 58 received study medication (ziprasidone, 31 patients; haloperidol, 27; age range, 21-72 years; 79% male). After the first injection, mean (95% CI) changes from baseline were 4.6 msec (0.4-8.9) with ziprasidone (n = 25) and 6.0 msec (1.4-10.5) with haloperidol (n = 24). After the second injection, these values were 12.8 msec (6.7-18.8) and 14.7 msec (10.2-19.2), respectively. Mild and transient changes in heart rate and blood pressure were observed with both treatments. None of the patients had a QTc interval >480 msec. Two patients in the ziprasidone group experienced QTc prolongation >450 msec (457 and 454 msec) and QTc changes that exceeded 60 msec (62 and 76 msec) relative to the time-matched baseline values. With haloperidol, QTc interval values were <450 msec with no changes >60 msec. Treatment-emergent AEs were reported in 29 of 31 patients (93.5%) in the ziprasidone group and 25 of 27 patients (92.6%) in the haloperidol group; most events were of mild or moderate severity. Frequently reported AEs were somnolence (90.3% and 81.5%, respectively), dizziness (22.6% and 7.4%), anxiety (16.1% and 7.4%), extrapyramidal symptoms (6.5% and 33.3%), agitation (6.5% and 18.5%), and insomnia (0% and 14.8%). CONCLUSIONS: In this study of the effects of high-dose ziprasidone and haloperidol in patients with schizophrenic disorder, none of the patients had a QTc interval >480 msec, and changes from baseline QTc interval were clinically modest with both drugs. Both drugs were generally well tolerated.

Effects of Oral Ziprasidone and Oral Haloperidol on QTc interval in patients with Schizophrenia or Schizoaffective disorder.

STUDY OBJECTIVE: To characterize the effect of oral ziprasidone and haloperidol on the corrected QT (QTc) interval under steady-state conditions. Design. Prospective, randomized, open-label, parallel-group study. SETTING: Inpatient clinical research facility. Patients Fifty-nine adults (age range 25-59 yrs) with schizophrenia or schizoaffective disorder who had no clinically significant abnormality on electrocardiogram (ECG) at screening. Intervention. During period 1 (days -10 to -4), antipsychotic and anticholinergic drugs were tapered. On the first day (day -3) of period 2, the drugs were discontinued, and placebo was given for the next 3 days (days -2 to 0). On the last day (day 0) of period 2, serial baseline ECGs were collected. During period 3 (days 1-16), patients received escalating oral doses of ziprasidone and haloperidol to reach steady state. Period 4 (days 17-19) allowed for study drug washout and initiation of outpatient antipsychotic therapy; safety assessments were also performed during this period. MEASUREMENTS AND RESULTS: At each steady-state dose level, three ECGs and a serum or plasma sample were collected at the predicted time of peak exposure to the administered drug. Point estimates and 95% confidence intervals (CIs) were determined for the mean QTc interval at baseline and for the mean change from baseline in QTc at each steady-state dose level. Mean changes from baseline in the QTc interval (msec) for ziprasidone were 4.5 (95% CI 1.9-7.1), 19.5 (95% CI 15.5-23.4), and 22.5 (95% CI 15.7- 29.4) for steady-state doses of 40, 160, and 320 mg/day, respectively; for haloperidol, -1.2 (95% CI -4.1-1.7), 6.6 (95% CI 1.6-11.7), and 7.2 (95% CI 1.4-13.1) for steady-state doses of 2.5, 15, and 30 mg/day. Although no patient in either treatment group experienced a QTc interval of 450 msec or greater, the QTc interval increased 30 msec or more in 11 and 17 ziprasidone-treated patients at 160 and 320 mg/day, respectively, and in 3 and 5 haloperidol-treated patients at 15 and 30 mg/day, respectively. Most treatment-emergent adverse drug reactions were mild in intensity, and none were severe. CONCLUSION: The QTc interval in ziprasidone- and haloperidol-treated patients increased with dose. Treatment with high doses of ziprasidone or haloperidol did not result in any patient experiencing a QTc interval of 450 msec or greater.

Tolerability of oral ziprasidone in children and adolescents with bipolar mania, schizophrenia, or schizoaffective disorder.

OBJECTIVE: This study characterizes the tolerability of ziprasidone in children and adolescents with bipolar mania, schizophrenia, or schizoaffective disorder. METHOD: Sixty-three subjects (aged 10-17 years) entered an open-label study consisting of a 3-week fixed-dose period (Period 1) and a subsequent 24-week flexible-dose period (Period 2). In Period 1, subjects received ziprasidone 80 or 160 mg/d in two divided doses, titrated over 10 days. In Period 2, subjects received flexible doses (20-160 mg/d). Tolerability was evaluated using movement rating scales, laboratory tests, and electrocardiograms. Clinical response was assessed using the Young Mania Rating Scale, the Brief Psychiatric Rating Scale-Anchored Version, and the Clinical Global Impressions-Severity scale. RESULTS: Adverse events (AEs) occurred mostly during dose titration and in the high-dose (160 mg/d) group. The most common AEs during Period 1 were sedation (32%), somnolence (30%), and nausea (25%) and during Period 2 were sedation (30%), somnolence (30%), and headache (25%). The incidence of movement disorder AEs was 22% and 16% during Periods 1 and 2, respectively. Six percent of study participants discontinued study participation due to AEs during Period 1 and 20% discontinued in Period 2. Thirty-three percent of subjects gained >or=7% of their baseline weight. No Fridericia-corrected QT (QTcF) intervals of >450 ms were observed during Period 1 and only one occurred during Period 2. No QTcF increase >or=60 ms from baseline was observed. Symptom reductions were observed in all patient groups. CONCLUSIONS: No unexpected tolerability findings were observed in this prospective trial of ziprasidone in children and adolescents with bipolar mania, schizophrenia, or schizoaffective disorder. On the basis of the results, a starting dose of 20 mg/d titrated to between 80 and 160 mg/d over 1-2 weeks appears optimal for most patients.

The effect of food on the absorption of oral ziprasidone.

Oral ziprasidone bioavailability is increased when taken with food. Here we describe two pharmacokinetic studies to quantify the impact of food on ziprasidone absorption in healthy volunteers. The first, an open-label, six-way crossover study, investigated ziprasidone absorption in eight healthy men. Subjects received oral ziprasidone (20, 40, and 80 mg) after an 8-hour fast or immediately following a US Food and Drug Administration standard meal (50% fat). In this study, area under the serum concentration- time curve (AUC) was greater in fed than in fasting states at each dose (20 mg, +48%; 40 mg, +87%; 80 mg, +101%). Under fasting conditions, increases in AUC and maximum drug concentration (Cmax) were less than dose-proportional; under fed conditions, they were dose-proportional. The second, an open-label, randomized, three-way crossover study, explored the impact of dietary fat on ziprasidone absorption in 14 healthy subjects. Subjects received ziprasidone (40 mg) under three conditions: fasting, with a high-fat meal (60% fat), and with a moderate-fat (30% fat) meal. AUC and Cmax under fed conditions increased by 104% and 84% (60%-fat meal) and 79% and 98% (30%-fat meal) , respectively, relative to the fasting state. There was no clear difference in ziprasidone bioavailability between the fed groups, suggesting that meal fat content is not a major determinant of bioavailability. Less pharmacokinetic variability was observed in the fed state, suggesting more consistent absorption of ziprasidone. These results demonstrate that administration of ziprasidone with food is crucial to ensure optimal, reliable dose-dependent bioavailability and thus predictable symptom control and tolerability.

Single-dose pharmacokinetics and safety of ziprasidone in children and adolescents.

OBJECTIVE: The purpose of this study was to provide single-dose pharmacokinetic, safety, and tolerability data for ziprasidone in youths with tic disorder, for comparison to adult studies to discern whether ziprasidone pediatric dosing could be modeled from adult data. METHOD: A single-dose, open-label study of ziprasidone was conducted in youths (ages 7-16 years) with Tourette's disorder or chronic tic disorder. Dosing of ziprasidone oral suspension (40 mg/mL) was weight adjusted: >60 kg, 20 mg (group 1, n = 8); 31 to 60 kg, 10 mg (group 2, n = 8); and 16 to 30 kg, 5 mg (group 3, n = 8). Patients were assessed for serum ziprasidone concentration, safety, tolerability, and electrocardiogram pre- and postdose. RESULTS: Twenty-four patients were evaluated for safety and tolerability, and 23 were evaluated for pharmacokinetics. Regression analysis of AUC(0-infinity) and Cmax values versus weight-normalized dose showed linear, dose-related changes in ziprasidone exposure. Ziprasidone was well tolerated with frequent, although transient, somnolence. No clinically significant change from baseline was observed in Bazett's or Fridericia's corrected QT(c) interval, and change in QT(c) interval was not related to serum ziprasidone concentration. CONCLUSIONS: Oral ziprasidone exhibited linear pharmacokinetics and dose-related exposure in youths with Tourette's disorder or chronic tic disorder, which are comparable to adult data. A single dose of ziprasidone was well tolerated without clinically significant effects on electrocardiograms collected around the time of maximum serum concentration.

Pharmacokinetics, safety, and tolerability of intramuscular ziprasidone in healthy volunteers.

Little has been published regarding the pharmacokinetics of the intramuscular (IM) formulation of Ziprasidone. The authors report results from 2 early phase I studies in healthy volunteers: a trial of single 5-, 10-, or 20-mg IM doses of ziprasidone in 24 subjects and an open-label 3-way crossover trial of 5-mg intravenous (IV), 5-mg IM, and 20-mg oral ziprasidone in 12 subjects. Absorption of IM ziprasidone was rapid (Tmax < 1 hour). The IM pharmacokinetic profile was consistent between studies and linear, with dose-related increases in exposure observed. The mean IM elimination t(1/2) was short and approximately 2.5 hours. The mean bioavailability for the 5-mg IM ziprasidone dose was approximately 100%. Adverse events were generally mild to moderate, and no subjects were discontinued from the study. No significant effects on renal function or other laboratory values were noted. These results support the use of IM ziprasidone in treating acutely agitated patients with schizophrenia.

A randomized evaluation of the effects of six antipsychotic agents on QTc, in the absence and presence of metabolic inhibition.

Many drugs have been associated with QTc prolongation and, in some cases, this is augmented by concomitant administration with metabolic inhibitors. The effects of 6 antipsychotics on the QTc interval at and around the time of estimated peak plasma/serum concentrations in the absence and presence of metabolic inhibition were characterized in a prospective, randomized study in which patients with psychotic disorders reached steady-state on either haloperidol 15 mg/d (n = 27), thioridazine 300 mg/d (n = 30), ziprasidone 160 mg/d (n = 31), quetiapine 750 mg/d (n = 27), olanzapine 20 mg/d (n = 24), or risperidone 6-8 mg/d increased to 16 mg/d (n = 25/20). Electrocardiograms (ECGs) were done at estimated Cmax at steady-state on both antipsychotic monotherapy and after concomitant administration of appropriate cytochrome P-450 (CYP450) inhibitor(s). Mean QTc intervals did not exceed 500 milliseconds in any patient taking any of the antipsychotics studied, in the absence or presence of metabolic inhibition. The mean QTc interval change was greatest in the thioridazine group, both in the presence and absence of metabolic inhibition. The presence of metabolic inhibition did not significantly augment QTc prolongation associated with any agent. Each of the antipsychotics studied was associated with measurable QTc prolongation at steady-state peak plasma concentrations, which was not augmented by metabolic inhibition. The theoretical risk of cardiotoxicity associated with QTc prolongation should be balanced against the substantial clinical benefits associated with atypical antipsychotics and the likelihood of other toxicities.

Pharmacodynamics of ziprasidone in children and adolescents: impact on dopamine transmission.

OBJECTIVE: Ziprasidone is an atypical antipsychotic with a high ratio of 5-HT(2A) to D(2) receptor antagonism. It is also an agonist at 5-HT(1A), which has been shown in rats to increase dopamine in prefrontal cortex. The objective of this study was to probe the dopamine agonist and antagonist pharmacodynamic properties of ziprasidone in youth. METHOD: A single-dose, open-label study was conducted in 24 youths, 7 to 16 years of age, with Tourette syndrome or chronic tic disorder. Ziprasidone oral suspension (40 mg/mL) was given to achieve 0.2 to 0.3 mg/kg. Patients were subsequently assessed for serum ziprasidone, serum prolactin, and eye blink rates. RESULTS: Serum ziprasidone peaked 4 hours postdose. Prolactin (baseline mean 7.2 ng/mL, 95% confidence interval [CI] 5.2-9.2) peaked at 4 hours (mean 27.5 ng/mL, 95% CI 22.6-32.3). Eyeblink rates per 5 minutes (baseline mean 60, 95% CI 42-79) peaked at 6 hours (mean 74, 95% CI 52-96). CONCLUSIONS: Ziprasidone acutely blocks dopamine transmission, as indicated by increased prolactin levels, and, in a delayed fashion, appears to stimulate dopaminergic transmission, as indicated by the increase in spontaneous eye blinks. The mechanism of dopaminergic stimulation is presumed to be indirect, via 5-HT(1A) agonism.

Ziprasidone metabolism, aldehyde oxidase, and clinical implications.

Ziprasidone (Geodon, Zeldox), a recently approved atypical antipsychotic agent for the treatment of schizophrenia, undergoes extensive metabolism in humans with very little (<5%) of the dose excreted as unchanged drug. Two enzyme systems have been implicated in ziprasidone metabolism: the cytosolic enzyme, aldehyde oxidase, catalyzes the predominant reductive pathway, and cytochrome P4503A4 (CYP3A4) is responsible for two alternative oxidation pathways. The involvement of two competing pathways in ziprasidone metabolism greatly reduces the potential for pharmacokinetic interactions between ziprasidone and other drugs. Because CYP3A4 only mediates one third of ziprasidone metabolism, the likelihood of interactions between ziprasidone and CYP3A4 inhibitors/ substrates is low. Furthermore, aldehyde oxidase activity does not appear to be altered when drugs or xenobiotics are coadministered. Aldehyde oxidase, a molybdenum-containing enzyme, catalyzes the oxidation of N-heterocyclic drugs such as famciclovir and zaleplon, in addition to reducing some agents such as zonisamide. Both reactions can occur simultaneously. Although in vitro inhibitors of aldehyde oxidase have been identified, there are no reported clinical interactions with aldehyde oxidase inhibitors or inducers. There is no evidence of genetic polymorphism in aldehyde oxidase, and thus it not surprising that ziprasidone exposure demonstrates unimodality in humans. Aldehyde oxidase is unrelated to the similarly named enzyme aldehyde dehydrogenase, which is predominantly responsible for the oxidation of acetaldehyde during ethanol metabolism. Consequently, it is unlikely that there would be any pharmacokinetic interaction between ethanol and ziprasidone.

The anxiolytic effect of the novel antipsychotic ziprasidone compared with diazepam in subjects anxious before dental surgery.

The novel atypical antipsychotic ziprasidone has a pharmacologic profile notable for potent agonism of serotonin (5-HT)1A receptors, antagonism at 5-HT1D receptors, and reuptake inhibition of norepinephrine. 5-HT1A receptor agonism, in particular, suggests anxiolytic activity, and ziprasidone has shown preliminary efficacy in treating the symptoms of anxiety associated with psychotic disorders. In this study, the anxiolytic efficacy of ziprasidone was evaluated in nonpsychotic subjects who were anxious before undergoing minor dental surgery. We compared a single oral dose of 20 mg ziprasidone (N = 30) with that of 10 mg diazepam (N = 30) and placebo (N = 30) in a randomized, parallel-group, double-blind study. The peak anxiolytic effect of ziprasidone compared with that of placebo was similar to that of diazepam but had a later onset. At 3 hours postdose, the anxiolytic effect of ziprasidone was significantly greater than that of placebo (p < 0.05) and somewhat greater than that of diazepam. Diazepam showed a significantly greater anxiolytic effect than placebo at 1 hour (p < 0.05) but not at 3 hours. The sedative effect of ziprasidone was never greater than that of placebo, whereas that of diazepam was significantly greater than that of placebo 1 to 1.5 hours postdose. Ziprasidone was generally well tolerated. Only one patient reported treatment-related adverse events (nausea and vomiting) and, unlike diazepam, ziprasidone did not cause reductions in blood pressure. Dystonia, extrapyramidal syndrome, akathisia, and postural hypotension were not seen with ziprasidone. Thus, ziprasidone may possess anxiolytic effects in addition to its antipsychotic properties.