Drug Interactions between hydroxyzine and Seroquel

Alcohol can increase the nervous system side effects of hydrOXYzine 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 hydrOXYzine. Do not use more than the recommended dose of hydrOXYzine, 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.

Grapefruit or grapefruit juice should not be consumed during treatment with QUEtiapine. Grapefruit juice can significantly increase the blood levels and effects of QUEtiapine, which can increase the risk and/or severity of side effects including drowsiness; dry mouth; constipation; increased appetite; weight gain; increased blood sugar and cholesterol or triglyceride levels; cognitive and motor impairment; involuntary muscle movements involving the face, tongue, or other parts of the body; difficulty swallowing; and seizures. Consuming grapefruit juice together with QUEtiapine may also increase the risk of two potentially life-threatening, but uncommon conditions: serotonin syndrome and a change in the electrical activity of your heart called QT prolongation. Immediate medical attention is required if you experience symptoms of either condition such as: nausea, vomiting, and diarrhea; agitation; confusion; fast or irregular heartbeat; sweating; flushing; seizures; hallucinations; blood pressure changes; shaking, stiff muscles, or muscle twitching; dizziness; high body temperature; loss of coordination; lightheadedness; and/or fainting. You might be more susceptible to QT prolongation if you have heart problems, uncontrolled hypothyroidism, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). It is best to avoid or limit the consumption of alcohol, as it can increase drowsiness or other nervous system side effects of QUEtiapine. Extended-release formulations of QUEtiapine should be taken without food or with a light meal. Talk to your doctor if you have any questions or concerns. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

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 use of neuroleptic agents is contraindicated in patients with acute alcohol intoxication exhibiting depressed vital signs. The central nervous system depressant effects of neuroleptic agents may be additive with those of alcohol. Severe respiratory depression and respiratory arrest may occur. Therapy with neuroleptic agents should be administered cautiously in patients who might be prone to acute alcohol intake.

The use of neuroleptic agents is contraindicated in comatose patients and patients with severe central nervous system depression. Neuroleptic agents may potentiate the CNS and respiratory depression in these patients.

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.

Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term trials; these trials did not show increased risk in patients older than 24 years and risk was reduced in patients 65 years and older. Adult and pediatric patients with major depressive disorder may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressants; this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders; such disorders are the strongest predictors of suicide. Patients of all ages treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behavior, especially during the first few months of drug therapy, and at times of dose changes. Family members/caregivers should be advised to monitor for changes in behavior and to notify the health care provider. Changing the therapeutic regimen (including discontinuing the medication) should be considered in patients whose depression is persistently worse, or who are experiencing emergent suicidal thoughts or behaviors.

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.

Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term trials; these trials did not show increased risk in patients older than 24 years and risk was reduced in patients 65 years and older. Adult and pediatric patients with major depressive disorder may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressants; this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders; such disorders are the strongest predictors of suicide. Patients of all ages treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behavior, especially during the first few months of drug therapy, and at times of dose changes. Family members/caregivers should be advised to monitor for changes in behavior and to notify the health care provider. Changing the therapeutic regimen (including discontinuing the medication) should be considered in patients whose depression is persistently worse, or who are experiencing emergent suicidal thoughts or behaviors.

A variety of abnormal thinking and behavior changes have been reported to occur in association with the use of most anxiolytics, sedatives and hypnotics. Some of these changes include decreased inhibition, aggressiveness, agitation, and hallucinations. These drugs can cause or exacerbate mental depression and cause suicidal behavior and ideation. Therapy with these drugs should be administered cautiously in patients with a history of depression or other psychiatric disorders. Patients should be monitored for any changes in mood or behavior. It may be prudent to refrain from dispensing large quantities of medication to these patients.

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.

Hydroxyzine is contraindicated in patients with a QT prolonged interval. Cases of QT prolongation and Torsade de Pointes have been reported during postmarketing studies. Most of the cases reported occurred in patients with other risk factors for QT prolongation, such as preexisting heart disease, electrolyte imbalances or arrhythmogenic drug use. Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, family history of long QT syndrome or other predisposing conditions, as well as myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

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.

Hydroxyzine is contraindicated in patients with a QT prolonged interval. Cases of QT prolongation and Torsade de Pointes have been reported during postmarketing studies. Most of the cases reported occurred in patients with other risk factors for QT prolongation, such as preexisting heart disease, electrolyte imbalances or arrhythmogenic drug use. Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, family history of long QT syndrome or other predisposing conditions, as well as myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

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.

Hydroxyzine is contraindicated in patients with a QT prolonged interval. Cases of QT prolongation and Torsade de Pointes have been reported during postmarketing studies. Most of the cases reported occurred in patients with other risk factors for QT prolongation, such as preexisting heart disease, electrolyte imbalances or arrhythmogenic drug use. Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, family history of long QT syndrome or other predisposing conditions, as well as myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

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.

The use of neuroleptic agents is contraindicated in comatose patients and patients with severe central nervous system depression. Neuroleptic agents may potentiate the CNS and respiratory depression in these patients.

Hydroxyzine is contraindicated in patients with a QT prolonged interval. Cases of QT prolongation and Torsade de Pointes have been reported during postmarketing studies. Most of the cases reported occurred in patients with other risk factors for QT prolongation, such as preexisting heart disease, electrolyte imbalances or arrhythmogenic drug use. Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, family history of long QT syndrome or other predisposing conditions, as well as myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

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.

It has been suggested that the anticholinergic effect of antihistamines may reduce the volume and cause thickening of bronchial secretions, resulting in obstruction of respiratory tract. Some manufacturers and clinicians recommend that therapy with antihistamines be administered cautiously in patients with asthma or chronic obstructive pulmonary disease.

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.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

Prolonged use of quetiapine was associated with the development of cataracts in dogs. Lens changes have also been observed in humans during chronic treatment with quetiapine, but a causal relationship has not been established. Long-term therapy with quetiapine should be administered cautiously in patients with a history of cataracts. Examination of the lens by slit lamp exam or other appropriately sensitive methods is recommended at initiation of treatment or shortly thereafter and at 6-month intervals during chronic treatment.

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.

It has been suggested that the anticholinergic effect of antihistamines may reduce the volume and cause thickening of bronchial secretions, resulting in obstruction of respiratory tract. Some manufacturers and clinicians recommend that therapy with antihistamines be administered cautiously in patients with asthma or chronic obstructive pulmonary disease.

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.

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.

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.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

Some hypnotic drugs can have an anticholinergic effect and should be used with caution in patients with glaucoma, and trouble urinating due to retention or enlarged prostate.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

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.

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.

According to the manufacturer, patients treated with quetiapine in 3- to 6-week placebo-controlled trials had increases in cholesterol and triglyceride of 11% and 17%, respectively, compared to slight decreases in the placebo group. Patients with preexisting hyperlipidemia may require closer monitoring during quetiapine therapy, and adjustments made accordingly in their lipid-lowering regimen.

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 quetiapine may be associated with in increase systolic and diastolic blood pressure in children and adolescents. During the 26 week open-label clinical trial, one child with a reported history of hypertension experienced a hypertensive crisis. Blood pressure in children and adolescents should be measured at the beginning of, and periodically during treatment with quetiapine.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

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.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

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.

The use of quetiapine may be associated with transient, asymptomatic elevations in serum transaminase. During a series of 3- to 6-week clinical trials, 6% of patients exposed to quetiapine experienced ALT (SGPT) elevations greater than three times the upper limit of normal, compared to 1% in the placebo group. Liver enzymes tended to increase within the first 3 weeks of therapy and return to baseline with continued treatment. Therapy with quetiapine should be administered cautiously in patients with signs and symptoms of hepatic impairment. Periodic assessment of serum transaminases should be performed in patients with significant hepatic disease.

Most neuroleptic agents are extensively metabolized by the liver. The plasma concentrations of these agents may be increased and the half-lives prolonged in patients with impaired hepatic function. Therapy with neuroleptic agents should be administered cautiously in patients with significant liver disease. Lower initial dosages and slower titration may be appropriate.

Limited pharmacokinetic data are available for the older, first-generation antihistamines. Many appear to be primarily metabolized by the liver, and both parent drugs and metabolites are excreted in the urine. Patients with renal and/or liver disease may be at greater risk for adverse effects from antihistamines due to drug and metabolite accumulation. Therapy with antihistamines should be administered cautiously in such patients. Lower initial dosages may be appropriate.

Some anxiolytics, sedatives and hypnotics are extensively metabolized by the liver, and excreted in the urine. Patients with impaired renal and/or hepatic function may be at greater risk for adverse effects, including central nervous system and respiratory depression, due to drug and metabolite accumulation. Therapy with these drugs should be administered cautiously in such patients, with careful dose selection usually starting at the low end of the dosing range.

In general, anxiolytics, sedatives and hypnotics are extensively metabolized by the liver. Their plasma clearance may be decreased and their half-life prolonged in patients with impaired hepatic function. Therapy with these drugs should be administered cautiously in patients with liver disease (some are not recommended in severe liver impairment), and the dosage should be adjusted accordingly. Laboratory testing is recommended prior and during treatment.

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.

The use of neuroleptic agents is associated with pseudo-parkinsonian symptoms such as akinesia, bradykinesia, tremors, pill-rolling motion, cogwheel rigidity, and postural abnormalities including stooped posture and shuffling gait. The onset is usually 1 to 2 weeks following initiation of therapy or an increase in dosage. Older neuroleptic agents such as haloperidol are more likely to induce these effects, and their use may be contraindicated in patients with Parkinson's disease or parkinsonian symptoms.

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.

Some anxiolytics, sedatives and hypnotics are extensively metabolized by the liver, and excreted in the urine. Patients with impaired renal and/or hepatic function may be at greater risk for adverse effects, including central nervous system and respiratory depression, due to drug and metabolite accumulation. Therapy with these drugs should be administered cautiously in such patients, with careful dose selection usually starting at the low end of the dosing range.

Limited pharmacokinetic data are available for the older, first-generation antihistamines. Many appear to be primarily metabolized by the liver, and both parent drugs and metabolites are excreted in the urine. Patients with renal and/or liver disease may be at greater risk for adverse effects from antihistamines due to drug and metabolite accumulation. Therapy with antihistamines should be administered cautiously in such patients. Lower initial dosages may be appropriate.

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.

During clinical trials, the use of quetiapine was associated with a dose-related decrease in total and free thyroxine (T4) levels that reached approximately 20% at the higher end of the therapeutic dose range and peaked within the first 2 to 4 weeks of treatment. Generally, the changes were of no clinical significance and were reversible following discontinuation of quetiapine regardless of the duration of treatment. TBG levels were not altered in any patient, while TSH increased in 0.4% (10/2386) of patients, some of whom required thyroid replacement therapy. Therapy with quetiapine should be administered cautiously in patients with thyroid disease. Closer monitoring of thyroid function may be appropriate following initiation or cessation of quetiapine.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

Some hypnotic drugs can have an anticholinergic effect and should be used with caution in patients with glaucoma, and trouble urinating due to retention or enlarged prostate.

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.