Drug Interactions between iloperidone and ombitasvir / paritaprevir / ritonavir

Ritonavir should be taken with food to lessen gastrointestinal side effects. It is important that you take this medication exactly as prescribed by your doctor. Do not change your treatment or stop treatment without first talking to your doctor.

Alcohol can increase the nervous system side effects of iloperidone such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with iloperidone. Do not use more than the recommended dose of iloperidone, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

Food significantly increases the absorption of paritaprevir. You should take each dose of paritaprevir with a meal. Taking it on an empty stomach may lead to inadequate blood levels and reduced effectiveness of the medication.

Some atypical antipsychotic agents can prolong the QTc interval of the electrocardiogram in a dose-dependent manner. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of these agents on the QT interval and should be corrected prior to institution of therapy. In addition, patients who experience frequent, severe, or prolonged diarrhea may be subject to electrolyte losses and should be followed closely and managed accordingly during therapy with these agents. Atypical antipsychotic agents should be avoided in patients with a history of cardiac arrhythmias or other conditions that may increase the risk of torsade de pointes and/or sudden death, including bradycardia; hypokalemia or hypomagnesemia; and congenital long QT syndrome.

Some atypical antipsychotic agents can prolong the QTc interval of the electrocardiogram in a dose-dependent manner. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of these agents on the QT interval and should be corrected prior to institution of therapy. In addition, patients who experience frequent, severe, or prolonged diarrhea may be subject to electrolyte losses and should be followed closely and managed accordingly during therapy with these agents. Atypical antipsychotic agents should be avoided in patients with a history of cardiac arrhythmias or other conditions that may increase the risk of torsade de pointes and/or sudden death, including bradycardia; hypokalemia or hypomagnesemia; and congenital long QT syndrome.

Antipsychotic drugs are not approved for the treatment of patients with dementia-related psychosis. Older patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death; although the causes were varied, most of the deaths appeared to be either cardiovascular (e.g., heart failure, sudden death) or infectious (e.g., pneumonia) in nature. A causal relationship with antipsychotic use has not been established. In controlled trials in older patients with dementia-related psychosis, patients randomized to risperidone, aripiprazole, and olanzapine had higher incidence of cerebrovascular adverse events (e.g., stroke, transient ischemic attack), including fatalities, compared to patients treated with placebo.

Some atypical antipsychotic agents can prolong the QTc interval of the electrocardiogram in a dose-dependent manner. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of these agents on the QT interval and should be corrected prior to institution of therapy. In addition, patients who experience frequent, severe, or prolonged diarrhea may be subject to electrolyte losses and should be followed closely and managed accordingly during therapy with these agents. Atypical antipsychotic agents should be avoided in patients with a history of cardiac arrhythmias or other conditions that may increase the risk of torsade de pointes and/or sudden death, including bradycardia; hypokalemia or hypomagnesemia; and congenital long QT syndrome.

Some atypical antipsychotic agents can prolong the QTc interval of the electrocardiogram in a dose-dependent manner. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of these agents on the QT interval and should be corrected prior to institution of therapy. In addition, patients who experience frequent, severe, or prolonged diarrhea may be subject to electrolyte losses and should be followed closely and managed accordingly during therapy with these agents. Atypical antipsychotic agents should be avoided in patients with a history of cardiac arrhythmias or other conditions that may increase the risk of torsade de pointes and/or sudden death, including bradycardia; hypokalemia or hypomagnesemia; and congenital long QT syndrome.

HBV reactivation has been reported during or after completion of HCV direct-acting antiviral therapy in HCV/HBV-coinfected patients who were not receiving HBV antiviral therapy; some cases resulted in fulminant hepatitis, hepatic failure, and death. Cases have been reported in hepatitis B surface antigen (HBsAg)-positive patients and patients with serologic evidence of resolved HBV infection (i.e., HBsAg negative and hepatitis B core antibody [anti-HBc] positive). HBV reactivation has also been reported in patients using certain immunosuppressant or chemotherapeutic agents; risk of HBV reactivation associated with HCV direct-acting antiviral therapy may be increased in these patients. All patients should be tested for evidence of current or prior HBV infection by measuring HBsAg and anti-HBc before starting HCV direct-acting antiviral therapy. Patients with serologic evidence of current or prior HBV infection should be monitored for clinical and laboratory signs of hepatitis flare or HBV reactivation during HCV therapy and posttherapy follow-up; appropriate patient management for HBV infection should be started as clinically indicated.

HBV reactivation has been reported during or after completion of HCV direct-acting antiviral therapy in HCV/HBV-coinfected patients who were not receiving HBV antiviral therapy; some cases resulted in fulminant hepatitis, hepatic failure, and death. Cases have been reported in hepatitis B surface antigen (HBsAg)-positive patients and patients with serologic evidence of resolved HBV infection (i.e., HBsAg negative and hepatitis B core antibody [anti-HBc] positive). HBV reactivation has also been reported in patients using certain immunosuppressant or chemotherapeutic agents; risk of HBV reactivation associated with HCV direct-acting antiviral therapy may be increased in these patients. All patients should be tested for evidence of current or prior HBV infection by measuring HBsAg and anti-HBc before starting HCV direct-acting antiviral therapy. Patients with serologic evidence of current or prior HBV infection should be monitored for clinical and laboratory signs of hepatitis flare or HBV reactivation during HCV therapy and posttherapy follow-up; appropriate patient management for HBV infection should be started as clinically indicated.

The use of drugs containing paritaprevir in combination with ombitasvir and ritonavir is contraindicated in patients with moderate to severe hepatic impairment (Child-Pugh B and C). No dosage adjustment is required in patients with mild hepatic impairment (Child-Pugh A).

Some atypical antipsychotic agents can prolong the QTc interval of the electrocardiogram in a dose-dependent manner. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of these agents on the QT interval and should be corrected prior to institution of therapy. In addition, patients who experience frequent, severe, or prolonged diarrhea may be subject to electrolyte losses and should be followed closely and managed accordingly during therapy with these agents. Atypical antipsychotic agents should be avoided in patients with a history of cardiac arrhythmias or other conditions that may increase the risk of torsade de pointes and/or sudden death, including bradycardia; hypokalemia or hypomagnesemia; and congenital long QT syndrome.

The central dopaminergic blocking effects of neuroleptic agents may precipitate or aggravate a potentially fatal symptom complex known as neuroleptic malignant syndrome (NMS). NMS is observed most frequently when high-potency agents like haloperidol are administered intramuscularly, but may occur with any neuroleptic agent given for any length of time. Clinical manifestations of NMS include hyperpyrexia, muscle rigidity, altered mental status and autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac arrhythmias). Additional signs may include elevated creatine phosphokinase, myoglobinuria, and acute renal failure. Neuroleptic agents should not be given to patients with active NMS and should be immediately discontinued if currently being administered in such patients. In patients with a history of NMS, introduction or reintroduction of neuroleptic agents should be carefully considered, since NMS may recur.

New onset diabetes mellitus, exacerbation of preexisting diabetes mellitus, hyperglycemia, and some cases of diabetic ketoacidosis have been reported during postmarketing surveillance in HIV-infected patients treated with protease inhibitors. Some patients required either initiation or dosage adjustments of insulin or oral hypoglycemic agents for treatment of these events. In some cases, hyperglycemia persisted despite discontinuation of protease inhibitor therapy. A causal relationship has not been established between protease inhibitor therapy and these events. Monitoring patients for hyperglycemia, new onset diabetes mellitus, or exacerbation of diabetes mellitus should be considered during protease inhibitor therapy.

Antipsychotic and neuroleptic drugs can lower the seizure threshold and trigger seizures in a dose-dependent manner. This risk is greatest in patients with a history of seizures or with conditions that lower the seizure threshold. Therapy with these drugs should be administered cautiously in patients with a history of seizures or other predisposing factors, such as head trauma, CNS abnormalities, and alcoholism.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

Adult and pediatric patients with depression and other psychiatric disorders may experience worsening of their symptoms and may have the emergence of suicidal thoughts and behavior. Patients should be monitored appropriately and observed closely for worsening of their symptoms, suicidality or changes in their behavior, especially during the first few months of treatment, and at times of dose changes. Discontinuing the medication should be considered if symptoms are persistently worse, or abrupt in onset.

The chronic use of neuroleptic agents can cause persistent elevations in prolactin levels due to antagonism of dopamine D2 receptors. Based on in vitro data, approximately one-third of human breast cancers are thought to be prolactin-dependent. The clinical significance of this observation with respect to long-term neuroleptic therapy is unknown. Chronic administration of neuroleptic drugs has been associated with mammary tumorigenesis in rodent studies but not in human clinical or epidemiologic studies. Until further data are available, therapy with neuroleptic agents should be administered cautiously in patients with a previously detected breast cancer. Caution is also advised in patients with preexisting hyperprolactinemia. Hyperprolactinemia may suppress hypothalamic gonadotrophin releasing hormone (GnRH), resulting in reduced pituitary gonadotropin secretion. This, in turn, may inhibit reproductive function by impairing gonadal steroidogenesis in both female and male patients. Galactorrhea, amenorrhea, gynecomastia, and impotence have been reported in patients receiving prolactin-elevating compounds; however, the clinical significance of elevated serum prolactin levels is unknown for most patients. Long-standing hyperprolactinemia when associated with hypogonadism may lead to decreased bone density in both female and male patients.

Atypical antipsychotic agents with alpha-adrenergic blocking effects may cause priapism. The condition is characterized by prolonged, often painful erections lasting longer than 4 hours. If not treated promptly, priapism can cause irreversible damage to the erectile tissue. Therapy with these agents should be administered cautiously in patients with a history of priapism, conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia, thalassemia), or anatomical deformations of the penis (e.g., angulation, cavernosal fibrosis, Peyronie's disease). Patients who experience an erection lasting longer than 4 hours, whether painful or not, should immediately discontinue the drug and seek emergency medical attention.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

There have been reports of increased bleeding, including spontaneous skin hematomas and hemarthrosis, in patients with hemophilia type A and B treated with protease inhibitors; however, a causal relationship has not been established. In some patients, additional factor VIII was given. In more than half of the reported cases, protease inhibitor therapy was continued or reintroduced. Patients with hemophilia or other coagulation defects should be monitored closely for bleeding during protease inhibitor therapy.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

Adult and pediatric patients with depression and other psychiatric disorders may experience worsening of their symptoms and may have the emergence of suicidal thoughts and behavior. Patients should be monitored appropriately and observed closely for worsening of their symptoms, suicidality or changes in their behavior, especially during the first few months of treatment, and at times of dose changes. Discontinuing the medication should be considered if symptoms are persistently worse, or abrupt in onset.

Hyperglycemia, in some cases extreme and associated with ketoacidosis or hyperosmolar coma or death, has been reported with the use of atypical antipsychotic agents. Patients with diabetes should be monitored for worsening control of blood glucose when treated with these agents. It is recommended that patients with risk factors for diabetes mellitus starting treatment with atypical antipsychotics should undergo fasting blood glucose testing at the beginning of treatment, and periodically thereafter. Any patient treated with atypical antipsychotics should be monitored for symptoms of hyperglycemia including polydipsia, polyuria, polyphagia, and weakness. Patients who develop symptoms of hyperglycemia during treatment with atypical antipsychotics should undergo fasting blood glucose testing. In some cases, hyperglycemia has resolved when treatment with these agents was discontinued; however, some patients required continuation of anti-diabetic treatment despite discontinuation of the atypical antipsychotic drug.

New onset diabetes mellitus, exacerbation of preexisting diabetes mellitus, hyperglycemia, and some cases of diabetic ketoacidosis have been reported during postmarketing surveillance in HIV-infected patients treated with protease inhibitors. Some patients required either initiation or dosage adjustments of insulin or oral hypoglycemic agents for treatment of these events. In some cases, hyperglycemia persisted despite discontinuation of protease inhibitor therapy. A causal relationship has not been established between protease inhibitor therapy and these events. Monitoring patients for hyperglycemia, new onset diabetes mellitus, or exacerbation of diabetes mellitus should be considered during protease inhibitor therapy.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

Esophageal dysmotility and aspiration have been associated with the use of antipsychotic drugs. These drugs should be administered cautiously in patients at risk for aspiration pneumonia.

Antipsychotic and neuroleptic drugs can lower the seizure threshold and trigger seizures in a dose-dependent manner. This risk is greatest in patients with a history of seizures or with conditions that lower the seizure threshold. Therapy with these drugs should be administered cautiously in patients with a history of seizures or other predisposing factors, such as head trauma, CNS abnormalities, and alcoholism.

Ritonavir may prolong the PR interval in some patients. Postmarketing cases of second or third degree atrioventricular block have been reported. Ritonavir should be administered with caution in patients with underlying structural heart disease, preexisting conduction abnormalities, ischemic heart disease, and cardiomyopathies as these patients might be at increased risk for developing cardiac conduction abnormalities.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

Atypical antipsychotic drugs have been associated with undesirable alterations in lipid levels. While all agents in the class have been shown to produce some changes, each drug has its own specific risk profile. Before or soon after initiation of antipsychotic medications, a fasting lipid profile should be obtained at baseline and monitored periodically during treatment.

Treatment with ritonavir alone or in combination with other protease inhibitors (e.g., lopinavir, saquinavir, tipranavir, fosamprenavir) has resulted in substantial increases in the concentration of total cholesterol and triglycerides. These effects have also been reported with other protease inhibitors but may be the most dramatic with ritonavir. The clinical significance of these elevations is unclear. Marked elevation in triglyceride levels is a risk factor for development of pancreatitis. Triglyceride and cholesterol testing is recommended before starting ritonavir (with or without other protease inhibitors) and periodically during therapy. Lipid disorders should be managed as clinically appropriate.

The chronic use of neuroleptic agents can cause persistent elevations in prolactin levels due to antagonism of dopamine D2 receptors. Based on in vitro data, approximately one-third of human breast cancers are thought to be prolactin-dependent. The clinical significance of this observation with respect to long-term neuroleptic therapy is unknown. Chronic administration of neuroleptic drugs has been associated with mammary tumorigenesis in rodent studies but not in human clinical or epidemiologic studies. Until further data are available, therapy with neuroleptic agents should be administered cautiously in patients with a previously detected breast cancer. Caution is also advised in patients with preexisting hyperprolactinemia. Hyperprolactinemia may suppress hypothalamic gonadotrophin releasing hormone (GnRH), resulting in reduced pituitary gonadotropin secretion. This, in turn, may inhibit reproductive function by impairing gonadal steroidogenesis in both female and male patients. Galactorrhea, amenorrhea, gynecomastia, and impotence have been reported in patients receiving prolactin-elevating compounds; however, the clinical significance of elevated serum prolactin levels is unknown for most patients. Long-standing hyperprolactinemia when associated with hypogonadism may lead to decreased bone density in both female and male patients.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

Atypical antipsychotic agents with alpha-adrenergic blocking effects may cause priapism. The condition is characterized by prolonged, often painful erections lasting longer than 4 hours. If not treated promptly, priapism can cause irreversible damage to the erectile tissue. Therapy with these agents should be administered cautiously in patients with a history of priapism, conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia, thalassemia), or anatomical deformations of the penis (e.g., angulation, cavernosal fibrosis, Peyronie's disease). Patients who experience an erection lasting longer than 4 hours, whether painful or not, should immediately discontinue the drug and seek emergency medical attention.

Hepatotoxicity (including jaundice, clinical hepatitis, and hepatic transaminase elevations exceeding 5 times the upper limit of normal) has been reported in patients receiving ritonavir alone or in combination with other antiretroviral drugs. Ritonavir should be administered with caution in patients with preexisting liver diseases, liver enzyme abnormalities, or hepatitis; increased monitoring of AST/ALT should be considered in these patients, especially during the first 3 months of ritonavir therapy. Ritonavir is not recommended for use in patients with severe liver dysfunction.

Atypical antipsychotic agents with alpha-adrenergic blocking effects may cause priapism. The condition is characterized by prolonged, often painful erections lasting longer than 4 hours. If not treated promptly, priapism can cause irreversible damage to the erectile tissue. Therapy with these agents should be administered cautiously in patients with a history of priapism, conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia, thalassemia), or anatomical deformations of the penis (e.g., angulation, cavernosal fibrosis, Peyronie's disease). Patients who experience an erection lasting longer than 4 hours, whether painful or not, should immediately discontinue the drug and seek emergency medical attention.

Cases of leukopenia, neutropenia, and agranulocytosis have been reported with the use of atypical antipsychotic agents. Patients with preexisting low white blood cell count may be at increased risk. Therapy with these agents should be administered cautiously in patients with a history of, or predisposition to, decreased white blood cell or neutrophil counts. Clinical monitoring of hematopoietic function is recommended. At the first sign of a clinically significant decline in white blood cells, discontinuation of atypical antipsychotic therapy should be considered in the absence of other causative factors, and the patient closely monitored for fever or other signs and symptoms of infection.

Weight gain has been observed with atypical antipsychotic use. While all agents in the class have been shown to produce some changes, each drug has its own specific risk profile. When treating pediatric patients with atypical antipsychotic agents, weight gain should be monitored and assessed against that expected for normal growth. Monitor weight at baseline and frequently thereafter.

Hyperglycemia, in some cases extreme and associated with ketoacidosis or hyperosmolar coma or death, has been reported with the use of atypical antipsychotic agents. Patients with diabetes should be monitored for worsening control of blood glucose when treated with these agents. It is recommended that patients with risk factors for diabetes mellitus starting treatment with atypical antipsychotics should undergo fasting blood glucose testing at the beginning of treatment, and periodically thereafter. Any patient treated with atypical antipsychotics should be monitored for symptoms of hyperglycemia including polydipsia, polyuria, polyphagia, and weakness. Patients who develop symptoms of hyperglycemia during treatment with atypical antipsychotics should undergo fasting blood glucose testing. In some cases, hyperglycemia has resolved when treatment with these agents was discontinued; however, some patients required continuation of anti-diabetic treatment despite discontinuation of the atypical antipsychotic drug.

Atypical antipsychotic agents with alpha-adrenergic blocking effects may cause priapism. The condition is characterized by prolonged, often painful erections lasting longer than 4 hours. If not treated promptly, priapism can cause irreversible damage to the erectile tissue. Therapy with these agents should be administered cautiously in patients with a history of priapism, conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia, thalassemia), or anatomical deformations of the penis (e.g., angulation, cavernosal fibrosis, Peyronie's disease). Patients who experience an erection lasting longer than 4 hours, whether painful or not, should immediately discontinue the drug and seek emergency medical attention.

Atypical antipsychotic agents with alpha-adrenergic blocking effects may cause priapism. The condition is characterized by prolonged, often painful erections lasting longer than 4 hours. If not treated promptly, priapism can cause irreversible damage to the erectile tissue. Therapy with these agents should be administered cautiously in patients with a history of priapism, conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia, thalassemia), or anatomical deformations of the penis (e.g., angulation, cavernosal fibrosis, Peyronie's disease). Patients who experience an erection lasting longer than 4 hours, whether painful or not, should immediately discontinue the drug and seek emergency medical attention.

Antipsychotic and neuroleptic drugs can lower the seizure threshold and trigger seizures in a dose-dependent manner. This risk is greatest in patients with a history of seizures or with conditions that lower the seizure threshold. Therapy with these drugs should be administered cautiously in patients with a history of seizures or other predisposing factors, such as head trauma, CNS abnormalities, and alcoholism.

Atypical antipsychotic agents with alpha-adrenergic blocking effects may cause priapism. The condition is characterized by prolonged, often painful erections lasting longer than 4 hours. If not treated promptly, priapism can cause irreversible damage to the erectile tissue. Therapy with these agents should be administered cautiously in patients with a history of priapism, conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia, thalassemia), or anatomical deformations of the penis (e.g., angulation, cavernosal fibrosis, Peyronie's disease). Patients who experience an erection lasting longer than 4 hours, whether painful or not, should immediately discontinue the drug and seek emergency medical attention.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.

Tardive dyskinesia (TD) has occurred in patients treated with antipsychotic drugs; the syndrome consists of potentially irreversible, involuntary, dyskinetic movements. The risk appears highest in older patients (particularly older women) but it is not possible to predict which patients are likely to develop TD; whether antipsychotic drugs differ in their potential to cause TD is unknown. The risk of TD and the likelihood that it will become irreversible increase with the duration of therapy and the total cumulative dose. The syndrome can develop after relatively brief treatment periods, even at low dosages; it may also occur after discontinuation of therapy. TD may remit (partially or completely) upon discontinuation of antipsychotic therapy, although antipsychotic therapy itself may suppress (or partially suppress) signs/symptoms of TD, possibly masking the underlying process; the effect of symptomatic suppression on the long-term course of TD is unknown. In patients with preexisting drug-induced TD, initiating or increasing the dosage of antipsychotic therapy may temporarily mask the symptoms of TD but could eventually worsen the condition. In patients requiring chronic therapy, the lowest dose and shortest duration of therapy producing a satisfactory clinical response are recommended; the need for continued therapy should be reassessed periodically. If signs/symptoms of TD occur during antipsychotic therapy, discontinuation of the offending agent should be considered; however, some patients may require treatment despite the presence of TD.

Atypical antipsychotic agents with alpha-adrenergic blocking effects may cause priapism. The condition is characterized by prolonged, often painful erections lasting longer than 4 hours. If not treated promptly, priapism can cause irreversible damage to the erectile tissue. Therapy with these agents should be administered cautiously in patients with a history of priapism, conditions that may predispose them to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia, thalassemia), or anatomical deformations of the penis (e.g., angulation, cavernosal fibrosis, Peyronie's disease). Patients who experience an erection lasting longer than 4 hours, whether painful or not, should immediately discontinue the drug and seek emergency medical attention.

The use of atypical antipsychotic agents has been associated with orthostatic hypotension and syncope. Therapy with atypical antipsychotics should be administered cautiously in patients with hypotension or conditions that could be exacerbated by hypotension, such as a history of myocardial infarction, angina, or ischemic stroke. Patients with dehydration (e.g., due to severe diarrhea or vomiting) may be predisposed to hypotension and should also be managed carefully during therapy with atypical antipsychotics. Blood pressure should be monitored at regular intervals, particularly during dosage escalation or whenever dosage has been altered, and patients should be advised not to rise abruptly from a sitting or recumbent position.