Ziprasidone Hydrochloride: Package Insert and Label Information (Page 4 of 7)
6.2 Postmarketing Experience
The following adverse reactions have been identified during post-approval use of ziprasidone hydrochloride. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Adverse reaction reports not listed above that have been received since market introduction include rare occurrences of the following: Cardiac Disorders: Tachycardia, torsade de pointes (in the presence of multiple confounding factors), [see Warnings and Precautions (5.3)] ; Digestive System Disorders: Swollen Tongue; Reproductive System and Breast Disorders: Galactorrhea, priapism; Nervous System Disorders: Facial Droop, neuroleptic malignant syndrome, serotonin syndrome (alone or in combination with serotonergic medicinal products), tardive dyskinesia; Psychiatric Disorders: Insomnia, mania/hypomania; Skin and subcutaneous Tissue Disorders: Allergic reaction (such as allergic dermatitis, angioedema, orofacial edema, urticaria), rash, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS); Urogenital System Disorders: Enuresis, urinary incontinence; Vascular Disorders: Postural hypotension, syncope.
7 DRUG INTERACTIONS
Drug-drug interactions can be pharmacodynamic (combined pharmacologic effects) or pharmacokinetic (alteration of plasma levels). The risks of using ziprasidone in combination with other drugs have been evaluated as described below. All interactions studies have been conducted with oral ziprasidone. Based upon the pharmacodynamic and pharmacokinetic profile of ziprasidone, possible interactions could be anticipated:
7.1 Metabolic Pathway
Approximately two-thirds of ziprasidone is metabolized via a combination of chemical reduction by glutathione and enzymatic reduction by aldehyde oxidase. There are no known clinically relevant inhibitors or inducers of aldehyde oxidase. Less than one-third of ziprasidone metabolic clearance is mediated by cytochrome P450 catalyzed oxidation.
7.2 In Vitro Studies
An in vitro enzyme inhibition study utilizing human liver microsomes showed that ziprasidone had little inhibitory effect on CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4, and thus would not likely interfere with the metabolism of drugs primarily metabolized by these enzymes. There is little potential for drug interactions with ziprasidone due to displacement [see Clinical Pharmacology (12.3)] .
7.3 Pharmacodynamic Interactions
Ziprasidone should not be used with any drug that prolongs the QT interval
Given the primary CNS effects of ziprasidone, caution should be used when it is taken in combination with other centrally acting drugs.
Because of its potential for inducing hypotension, ziprasidone may enhance the effects of certain antihypertensive agents.
Ziprasidone may antagonize the effects of levodopa and dopamine agonists.
7.4 Pharmacokinetic Interactions
Carbamazepine is an inducer of CYP3A4; administration of 200 mg twice daily for 21 days resulted in a decrease of approximately 35% in the AUC of ziprasidone. This effect may be greater when higher doses of carbamazepine are administered.
Ketoconazole, a potent inhibitor of CYP3A4, at a dose of 400 mg QD for 5 days, increased the AUC and C max of ziprasidone by about 35 to 40%. Other inhibitors of CYP3A4 would be expected to have similar effects.
Cimetidine at a dose of 800 mg QD for 2 days did not affect ziprasidone pharmacokinetics.
The co-administration of 30 mL of Maalox ® with ziprasidone did not affect the pharmacokinetics of ziprasidone.
Ziprasidone at a dose of 40 mg twice daily administered concomitantly with lithium at a dose of 450 mg twice daily for 7 days did not affect the steady-state level or renal clearance of lithium. Ziprasidone dosed adjunctively to lithium in a maintenance trial of bipolar patients did not affect mean therapeutic lithium levels.
7.6 Oral Contraceptives
In vivo studies have revealed no effect of ziprasidone on the pharmacokinetics of estrogen or progesterone components. Ziprasidone at a dose of 20 mg twice daily did not affect the pharmacokinetics of concomitantly administered oral contraceptives, ethinyl estradiol (0.03 mg) and levonorgestrel (0.15 mg).
Consistent with in vitro results, a study in normal healthy volunteers showed that ziprasidone did not alter the metabolism of dextromethorphan, a CYP2D6 model substrate, to its major metabolite, dextrorphan. There was no statistically significant change in the urinary dextromethorphan/dextrorphan ratio.
A pharmacokinetic interaction of ziprasidone with valproate is unlikely due to the lack of common metabolic pathways for the two drugs. Ziprasidone dosed adjunctively to valproate in a maintenance trial of bipolar patients did not affect mean therapeutic valproate levels.
7.9 Other Concomitant Drug Therapy
Population pharmacokinetic analysis of schizophrenic patients enrolled in controlled clinical trials has not revealed evidence of any clinically significant pharmacokinetic interactions with benztropine, propranolol, or lorazepam.
7.10 Food Interaction
The absolute bioavailability of a 20 mg dose under fed conditions is approximately 60%. The absorption of ziprasidone is increased up to two-fold in the presence of food [see Clinical Pharmacology (12.3)] .
8 USE IN SPECIFIC POPULATIONS
Pregnancy Exposure Registry
There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to atypical antipsychotics, including ziprasidone, during pregnancy. Healthcare providers are encouraged to register patients by contacting the National Pregnancy Registry for Atypical Antipsychotics at 1-866-961-2388 or online at http://womensmentalhealth.org/clinical-and-research-programs/pregnancyregistry/.
Neonates exposed to antipsychotic drugs, including ziprasidone, during the third trimester are at risk for extrapyramidal and/or withdrawal symptoms following delivery (see Clinical Considerations). Overall available data from published epidemiologic studies of pregnant women exposed to ziprasidone have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes (see Data). There are risks to the mother associated with untreated schizophrenia or bipolar I disorder and with exposure to antipsychotics, including ziprasidone, during pregnancy (see Clinical Considerations).
In animal studies, ziprasidone administration to pregnant rats and rabbits during organogenesis caused developmental toxicity at doses similar to recommended human doses, and was teratogenic in rabbits at 3 times the maximum recommended human dose (MRHD). Rats exposed to ziprasidone during gestation and lactation exhibited increased perinatal pup mortality and delayed neurobehavioral and functional development of offspring at doses less than or similar to human therapeutic doses (see Data).
The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
Disease-associated maternal and/or embryo/fetal risk
There is risk to the mother from untreated schizophrenia or bipolar I disorder, including increased risk of relapse, hospitalization, and suicide. Schizophrenia and bipolar I disorder are associated with increased adverse perinatal outcomes, including preterm birth. It is not known if this is a direct result of the illness or other comorbid factors.
Fetal/neonatal adverse reactions
Extrapyramidal and/or withdrawal symptoms, including agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding disorder have been reported in neonates who were exposed to antipsychotic drugs, including ziprasidone, during the third trimester of pregnancy. These symptoms have varied in severity. Monitor neonates for extrapyramidal and/or withdrawal symptoms and manage symptoms appropriately. Some neonates recovered within hours or days without specific treatment; others required prolonged hospitalization.
Published data from observational studies, birth registries, and case reports on the use of atypical antipsychotics during pregnancy do not report a clear association with antipsychotics and major birth defects. A retrospective cohort study from a Medicaid database of 9258 women exposed to antipsychotics during pregnancy did not indicate an overall increased risk for major birth defects.
When ziprasidone was administered to pregnant rabbits during the period of organogenesis, an increased incidence of fetal structural abnormalities (ventricular septal defects and other cardiovascular malformations, and kidney alterations) was observed at a dose of 30 mg/kg/day (3 times the MRHD of 200 mg/day based on mg/m 2 body surface area). There was no evidence to suggest that these developmental effects were secondary to maternal toxicity. The developmental no effect dose was 10 mg/kg/day (equivalent to the MRHD based on a mg/m 2 body surface area). In rats, embryofetal toxicity (decreased fetal weights, delayed skeletal ossification) was observed following administration of 10 to 160 mg/kg/day (0.5 to 8 times the MRHD based on mg/m 2 body surface area) during organogenesis or throughout gestation, but there was no evidence of teratogenicity. Doses of 40 and 160 mg/kg/day (2 and 8 times the MRHD based on mg/m 2 body surface area) were associated with maternal toxicity. The developmental no-effect dose is 5 mg/kg/day (0.2 times the MRHD based on mg/m 2 body surface area).
There was an increase in the number of pups born dead and a decrease in postnatal survival through the first 4 days of lactation among the offspring of female rats treated during gestation and lactation with doses of 10 mg/kg/day (0.5 times the MRHD based on mg/m 2 body surface area) or greater. Offspring developmental delays (decreased pup weights) and neurobehavioral functional impairment (eye opening air righting) were observed at doses of 5 mg/kg/day (0.2 times the MRHD based on mg/m 2 body surface area) or greater. A no-effect level was not established for these effects.
Limited data from a published case report indicate the presence of ziprasidone in human milk. Although there are no reports of adverse effects on a breastfed infant exposed to ziprasidone via breast milk, there are reports of excess sedation, irritability, poor feeding, and extrapyramidal symptoms (tremors and abnormal muscle movements) in infants exposed to other atypical antipsychotics through breast milk (see Clinical Considerations). There is no information on the effects of ziprasidone on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for ziprasidone and any potential adverse effects on the breastfed child from ziprasidone or from the mother’s underlying condition.
Infants exposed to ziprasidone should be monitored for excess sedation, irritability, poor feeding, and extrapyramidal symptoms (tremors and abnormal muscle movements).
8.3 Females and Males of Reproductive Potential
Based on the pharmacologic action of ziprasidone (D2 antagonism), treatment with ziprasidone may result in an increase in serum prolactin levels, which may lead to a reversible reduction in fertility in females of reproductive potential [see Warnings and Precautions (5.15) and Nonclinical Toxicology (13.1)].
8.4 Pediatric Use
The safety and effectiveness of ziprasidone have not been established in pediatric patients.
8.5 Geriatric Use
Of the total number of subjects in clinical studies of ziprasidone, 2.4 percent were 65 and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. Nevertheless, the presence of multiple factors that might increase the pharmacodynamic response to ziprasidone, or cause poorer tolerance or orthostasis, should lead to consideration of a lower starting dose, slower titration, and careful monitoring during the initial dosing period for some elderly patients.
8.6 Renal Impairment
Because ziprasidone is highly metabolized, with less than 1% of the drug excreted unchanged, renal impairment alone is unlikely to have a major impact on the pharmacokinetics of ziprasidone. The pharmacokinetics of ziprasidone following 8 days of 20 mg twice daily dosing were similar among subjects with varying degrees of renal impairment (n=27), and subjects with normal renal function, indicating that dosage adjustment based upon the degree of renal impairment is not required. Ziprasidone is not removed by hemodialysis.
8.7 Hepatic Impairment
As ziprasidone is cleared substantially by the liver, the presence of hepatic impairment would be expected to increase the AUC of ziprasidone; a multiple-dose study at 20 mg twice daily for 5 days in subjects (n=13) with clinically significant (Childs-Pugh Class A and B) cirrhosis revealed an increase in AUC 0-12 of 13% and 34% in Childs-Pugh Class A and B, respectively, compared to a matched control group (n=14). A half-life of 7.1 hours was observed in subjects with cirrhosis compared to 4.8 hours in the control group.
8.8 Age and Gender Effects
In a multiple-dose (8 days of treatment) study involving 32 subjects, there was no difference in the pharmacokinetics of ziprasidone between men and women or between elderly (>65 years) and young (18 to 45 years) subjects. Additionally, population pharmacokinetic evaluation of patients in controlled trials has revealed no evidence of clinically significant age or gender-related differences in the pharmacokinetics of ziprasidone. Dosage modifications for age or gender are, therefore, not recommended.
Based on in vitro studies utilizing human liver enzymes, ziprasidone is not a substrate for CYP1A2; smoking should therefore not have an effect on the pharmacokinetics of ziprasidone. Consistent with these in vitro results, population pharmacokinetic evaluation has not revealed any significant pharmacokinetic differences between smokers and nonsmokers.
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