Interactions between Duravent and Thioridazine

Thioridazine has a major potential interaction with Abnormal Electrocardiogram.

The use of thioridazine is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Thioridazine can prolong the QT interval of the electrocardiogram in a dose-related manner. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. In a crossover study of nine patients, a single 50 mg dose of thioridazine increased the QTc interval by a mean maximum of 23 msec compared to placebo. During postmarketing experience, torsade de pointes and sudden death have been reported, although a causal relationship has not been determined. The manufacturer states that thioridazine should not be administered in patients with a baseline QTc interval greater than 450 msec, and that it should be discontinued in patients with QTc measurements exceeding 500 msec during therapy. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of thioridazine on the QT interval and should be corrected prior to institution of therapy. 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 thioridazine.

Thioridazine has a major potential interaction with Acute Alcohol Intoxication.

Phenothiazines are contraindicated in the presence of large amounts of central nervous system depressants such as alcohol. The risk of suicide and the danger of overdose may be increased in patients who use alcohol excessively. Phenothiazines should be used with caution in patients experiencing alcohol withdrawal.

Thioridazine has a major potential interaction with Alcoholism.

Phenothiazines are contraindicated in the presence of large amounts of central nervous system depressants such as alcohol. The risk of suicide and the danger of overdose may be increased in patients who use alcohol excessively. Phenothiazines should be used with caution in patients experiencing alcohol withdrawal.

Thioridazine has a major potential interaction with Altered Consciousness.

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

Thioridazine has a major potential interaction with Arrhythmia.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.

Thioridazine has a major potential interaction with Arrhythmia.

The use of thioridazine is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Thioridazine can prolong the QT interval of the electrocardiogram in a dose-related manner. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. In a crossover study of nine patients, a single 50 mg dose of thioridazine increased the QTc interval by a mean maximum of 23 msec compared to placebo. During postmarketing experience, torsade de pointes and sudden death have been reported, although a causal relationship has not been determined. The manufacturer states that thioridazine should not be administered in patients with a baseline QTc interval greater than 450 msec, and that it should be discontinued in patients with QTc measurements exceeding 500 msec during therapy. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of thioridazine on the QT interval and should be corrected prior to institution of therapy. 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 thioridazine.

The methscopolamine in Duravent has a moderate potential interaction with Arrhythmia.

Antimuscarinic agents block vagal inhibition of the SA nodal pacemaker. These agents should be administered cautiously in patients with tachycardia, congestive heart failure, or coronary artery disease. Premature ventricular depolarization or ventricular tachycardia or fibrillation associated with antimuscarinic drugs is rare.

The methscopolamine in Duravent has a moderate potential interaction with Arrhythmia.

Anticholinergics block vagal inhibition of the SA nodal pacemaker. Therapy with anticholinergics should be administered cautiously in patients with tachycardia, congestive heart failure, or coronary artery disease. Premature ventricular depolarization or ventricular tachycardia or fibrillation associated with anticholinergics is rare.

The methscopolamine in Duravent has a major potential interaction with Asthma.

The use of systemic anticholinergics is contraindicated in the treatment of lower respiratory tract symptoms including asthma. Muscarinic receptor antagonists reduce bronchial secretions, which can result in decreased fluidity and increased thickening of secretions. However, ipratropium does not produce these effects and can be used safely in treating asthma.

The chlorpheniramine in Duravent has a moderate potential interaction with Asthma.

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 methscopolamine in Duravent has a major potential interaction with Autonomic Neuropathy.

Agents with anticholinergic activity can exacerbate many of the manifestations of autonomic neuropathy, including tachycardia, anhidrosis, bladder atony, obstipation, dry mouth and eyes, cycloplegia and blurring of vision, and sexual impotence in males. Therapy with antimuscarinic agents and higher dosages of antispasmodic agents (e.g., dicyclomine or oxybutynin) should be administered cautiously in patients with autonomic neuropathy.

The phenylephrine in Duravent has a moderate potential interaction with Benign Prostatic Hyperplasia.

Sympathomimetic agents may cause or worsen urinary difficulty in patients with prostate enlargement due to smooth muscle contraction in the bladder neck via stimulation of alpha-1 adrenergic receptors. Therapy with sympathomimetic agents should be administered cautiously in patients with hypertrophy or neoplasm of the prostate.

The methscopolamine in Duravent has a moderate potential interaction with Bleeding Disorder.

Antimuscarinic agents may cause a delay in gastric emptying and possibly antral stasis in patients with gastric ulcer. Therapy with antimuscarinic agents should be administered cautiously to patients with gastric ulcer.

Thioridazine has a major potential interaction with Bone Marrow Depression/Low Blood Counts.

Phenothiazines may cause hematologic toxicity. In patients with preexisting blood dyscrasias, bone marrow suppression, or a history of drug-induced leukopenia or neutropenia, phenothiazines should not be used or are contraindicated. Complete blood counts should be regularly monitored in patients with risk factors for blood dyscrasias. If white blood cell counts indicate cellular depression, discontinue treatment and institute appropriate therapy.

Thioridazine has a moderate potential interaction with Breast Cancer.

The chronic use of phenothiazines is associated with persistent elevations in prolactin levels. The clinical significance in patients with a history of breast cancer is unknown and should be considered prior to therapy; approximately one-third of human breast cancers are thought to be prolactin-dependent. Chronic administration of neuroleptic drugs has been associated with mammary tumorigenesis in animal studies; however, evidence is inconclusive in humans.

The phenylephrine in Duravent has a major potential interaction with Cardiovascular Conditions and Disorders.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

Thioridazine has a major potential interaction with Cardiovascular Conditions and Disorders.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.

The methscopolamine in Duravent has a moderate potential interaction with Cardiovascular Conditions and Disorders.

Anticholinergics block vagal inhibition of the SA nodal pacemaker. Therapy with anticholinergics should be administered cautiously to patients with tachycardia, congestive heart failure, or coronary artery disease. Premature ventricular depolarization, ventricular tachycardia, and fibrillation associated with anticholinergics are rare.

The chlorpheniramine in Duravent has a moderate potential interaction with Cardiovascular Conditions and Disorders.

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.

Thioridazine has a moderate potential interaction with Central Nervous System Disorders.

Phenothiazines can lower the seizure threshold. Caution is recommended during administration in patients with a history of convulsive disorders or EEG abnormalities. Anticonvulsant therapy should be maintained or adequately adjusted during phenothiazine treatment.

The phenylephrine in Duravent has a major potential interaction with Cerebrovascular Insufficiency.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

Thioridazine has a major potential interaction with Cerebrovascular Insufficiency.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.

The chlorpheniramine in Duravent has a moderate potential interaction with COPD.

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.

Thioridazine has a major potential interaction with Dementia.

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.

The phenylephrine in Duravent has a moderate potential interaction with Diabetes Mellitus.

Sympathomimetic agents may cause increases in blood glucose concentrations. These effects are usually transient and slight but may be significant with dosages higher than those normally recommended. Therapy with sympathomimetic agents should be administered cautiously in patients with diabetes mellitus. Closer monitoring of blood glucose concentrations may be appropriate.

Thioridazine has a major potential interaction with Diarrhea.

The use of thioridazine is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Thioridazine can prolong the QT interval of the electrocardiogram in a dose-related manner. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. In a crossover study of nine patients, a single 50 mg dose of thioridazine increased the QTc interval by a mean maximum of 23 msec compared to placebo. During postmarketing experience, torsade de pointes and sudden death have been reported, although a causal relationship has not been determined. The manufacturer states that thioridazine should not be administered in patients with a baseline QTc interval greater than 450 msec, and that it should be discontinued in patients with QTc measurements exceeding 500 msec during therapy. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of thioridazine on the QT interval and should be corrected prior to institution of therapy. 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 thioridazine.

The methscopolamine in Duravent has a minor potential interaction with Diarrhea.

Diarrhea may be a symptom of incomplete intestinal obstruction, especially in patients with ileostomy or colostomy. Antimuscarinic agents may further aggravate the diarrhea. Therefore, these drugs should be administered cautiously in patients with diarrhea.

Thioridazine has a major potential interaction with Electrolyte Abnormalities.

The use of thioridazine is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Thioridazine can prolong the QT interval of the electrocardiogram in a dose-related manner. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. In a crossover study of nine patients, a single 50 mg dose of thioridazine increased the QTc interval by a mean maximum of 23 msec compared to placebo. During postmarketing experience, torsade de pointes and sudden death have been reported, although a causal relationship has not been determined. The manufacturer states that thioridazine should not be administered in patients with a baseline QTc interval greater than 450 msec, and that it should be discontinued in patients with QTc measurements exceeding 500 msec during therapy. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of thioridazine on the QT interval and should be corrected prior to institution of therapy. 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 thioridazine.

The methscopolamine in Duravent has a major potential interaction with Esophageal Obstruction.

Anticholinergics are contraindicated in patients with obstructive diseases such as achalasia, esophageal stricture or stenosis, pyloroduodenal stenosis, stenosing peptic ulcer, pyloric obstruction, and paralytic ileus. Anticholinergics may further suppress intestinal motility with resultant precipitation or aggravation of toxic megacolon.

The methscopolamine in Duravent has a minor potential interaction with Fever.

Atropine-like agents may increase the risk of hyperthermia in patients with fever by producing anhidrosis. Therapy with atropine-like agents should be administered cautiously in febrile patients.

The methscopolamine in Duravent has a major potential interaction with Gastrointestinal Obstruction.

Anticholinergics are contraindicated in patients with obstructive diseases such as achalasia, esophageal stricture or stenosis, pyloroduodenal stenosis, stenosing peptic ulcer, pyloric obstruction, and paralytic ileus. Anticholinergics may further suppress intestinal motility with resultant precipitation or aggravation of toxic megacolon.

The chlorpheniramine in Duravent has a moderate potential interaction with Gastrointestinal Obstruction.

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.

The methscopolamine in Duravent has a moderate potential interaction with GERD.

Antimuscarinic agents decrease gastric motility and relax the lower esophageal sphincter which promotes gastric retention and can aggravate reflux. These drugs should be administered cautiously in patients with gastroesophageal reflux or hiatal hernia associated with reflux esophagitis.

The methscopolamine in Duravent has a major potential interaction with Glaucoma/Intraocular Hypertension.

Anticholinergic agents are contraindicated in patients with primary glaucoma, a tendency toward glaucoma (narrow anterior chamber angle), or adhesions (synechiae) between the iris and lens, as well as for the elderly and others in whom undiagnosed glaucoma or excessive pressure in the eye may be present. Because anticholinergics cause mydriasis, they may exacerbate these conditions.

The chlorpheniramine in Duravent has a moderate potential interaction with Glaucoma/Intraocular Hypertension.

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.

The phenylephrine in Duravent has a moderate potential interaction with Glaucoma/Intraocular Hypertension.

Sympathomimetic agents can induce transient mydriasis via stimulation of alpha-1 adrenergic receptors. In patients with anatomically narrow angles or narrow-angle glaucoma, pupillary dilation can provoke an acute attack. In patients with other forms of glaucoma, mydriasis may occasionally increase intraocular pressure. Therapy with sympathomimetic agents should be administered cautiously in patients with or predisposed to glaucoma, particularly narrow-angle glaucoma.

Thioridazine has a major potential interaction with High Blood Pressure.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.

The methscopolamine in Duravent has a minor potential interaction with High Blood Pressure.

Cardiovascular effects of anticholinergics may exacerbate hypertension. Therapy with anticholinergic agents should be administered cautiously in patients with hypertension.

Thioridazine has a major potential interaction with History - Cerebrovascular Disease.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.

Thioridazine has a major potential interaction with History - Myocardial Infarction.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.

The phenylephrine in Duravent has a major potential interaction with Hyperthyroidism.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

The chlorpheniramine in Duravent has a moderate potential interaction with Hyperthyroidism.

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 methscopolamine in Duravent has a minor potential interaction with Hyperthyroidism.

In general, agents with anticholinergic activity may exacerbate hyperthyroidism. Therapy with anticholinergics should be administered cautiously in patients with hyperthyroidism. Thyroid levels should be monitored if usage is prolonged.

Thioridazine has a major potential interaction with Hypokalemia.

The use of thioridazine is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Thioridazine can prolong the QT interval of the electrocardiogram in a dose-related manner. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. In a crossover study of nine patients, a single 50 mg dose of thioridazine increased the QTc interval by a mean maximum of 23 msec compared to placebo. During postmarketing experience, torsade de pointes and sudden death have been reported, although a causal relationship has not been determined. The manufacturer states that thioridazine should not be administered in patients with a baseline QTc interval greater than 450 msec, and that it should be discontinued in patients with QTc measurements exceeding 500 msec during therapy. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of thioridazine on the QT interval and should be corrected prior to institution of therapy. 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 thioridazine.

Thioridazine has a major potential interaction with Hypotension.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.

The chlorpheniramine in Duravent has a moderate potential interaction with Hypotension.

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 methscopolamine in Duravent has a major potential interaction with Infectious Gastroenteritis.

The use of drugs with antiperistaltic activity (primarily antidiarrheal and antimuscarinic agents, but also antispasmodic agents such as dicyclomine or oxybutynin at high dosages) is contraindicated in patients with diarrhea due to pseudomembranous enterocolitis or enterotoxin-producing bacteria. These drugs may prolong and/or worsen diarrhea associated with organisms that invade the intestinal mucosa, such as toxigenic E. coli, Salmonella and Shigella, and pseudomembranous colitis due to broad-spectrum antibiotics. Other symptoms and complications such as fever, shedding of organisms and extraintestinal illness may also be increased or prolonged. In general, because antiperistaltic agents decrease gastrointestinal motility, they may delay the excretion of infective gastroenteric organisms or toxins and should be used cautiously in patients with any infectious diarrhea, particularly if accompanied by high fever or pus or blood in the stool. Some cough and cold and other combination products may occasionally include antimuscarinic agents for their drying effects and may, therefore, require careful selection when necessary.

The methscopolamine in Duravent has a moderate potential interaction with Ischemic Heart Disease.

Antimuscarinic agents block vagal inhibition of the SA nodal pacemaker. These agents should be administered cautiously in patients with tachycardia, congestive heart failure, or coronary artery disease. Premature ventricular depolarization or ventricular tachycardia or fibrillation associated with antimuscarinic drugs is rare.

Thioridazine has a major potential interaction with Liver Disease.

Therapy with phenothiazines should be administered cautiously or are contraindicated in patients with preexisting liver disease or with a history of jaundice due to phenothiazine hypersensitivity. Patients with a history of hepatic encephalopathy due to cirrhosis may have increased sensitivity to the central nervous system effects of some phenothiazines (e.g., chlorpromazine). Treatment should be discontinued if jaundice occurs.

The chlorpheniramine in Duravent has a moderate potential interaction with Liver Disease.

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.

Thioridazine has a major potential interaction with Magnesium Imbalance.

The use of thioridazine is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Thioridazine can prolong the QT interval of the electrocardiogram in a dose-related manner. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. In a crossover study of nine patients, a single 50 mg dose of thioridazine increased the QTc interval by a mean maximum of 23 msec compared to placebo. During postmarketing experience, torsade de pointes and sudden death have been reported, although a causal relationship has not been determined. The manufacturer states that thioridazine should not be administered in patients with a baseline QTc interval greater than 450 msec, and that it should be discontinued in patients with QTc measurements exceeding 500 msec during therapy. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of thioridazine on the QT interval and should be corrected prior to institution of therapy. 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 thioridazine.

The methscopolamine in Duravent has a major potential interaction with Myasthenia Gravis.

Because antimuscarinic agents have anticholinergic effects, they are contraindicated in patients with myasthenia gravis. Their use may be appropriate to reduce adverse muscarinic effects caused by an anticholinesterase agent.

Thioridazine has a moderate potential interaction with Neuroleptic Malignant Syndrome.

Therapy with phenothiazines may precipitate or aggravate a potentially fatal symptom complex known as neuroleptic malignant syndrome (NMS). Treatment should not be initiated in patients with active NMS, and should be immediately discontinued if currently administered in such patients. In patients with a history of NMS, introduction or reintroduction of phenothiazines should be carefully considered, since NMS may recur.

The phenylephrine in Duravent has a major potential interaction with Pheochromocytoma.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

Thioridazine has a major potential interaction with Pheochromocytoma.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.

The phenylephrine in Duravent has a moderate potential interaction with Prostate Tumor, Benign.

Sympathomimetic agents may cause or worsen urinary difficulty in patients with prostate enlargement due to smooth muscle contraction in the bladder neck via stimulation of alpha-1 adrenergic receptors. Therapy with sympathomimetic agents should be administered cautiously in patients with hypertrophy or neoplasm of the prostate.

The chlorpheniramine in Duravent has a moderate potential interaction with Renal Dysfunction.

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.

Thioridazine has a major potential interaction with Respiratory Arrest.

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

Thioridazine has a moderate potential interaction with Seizures.

Phenothiazines can lower the seizure threshold. Caution is recommended during administration in patients with a history of convulsive disorders or EEG abnormalities. Anticonvulsant therapy should be maintained or adequately adjusted during phenothiazine treatment.

The methscopolamine in Duravent has a moderate potential interaction with Ulcerative Colitis.

Antimuscarinic agents may suppress intestinal motility and produce paralytic ileus with resultant precipitation of toxic megacolon. These drugs should be administered cautiously to patients with ulcerative colitis.

The methscopolamine in Duravent has a major potential interaction with Urinary Retention.

In general, the use of anticholinergic agents is contraindicated in patients with urinary retention and bladder neck obstruction caused by prostatic hypertrophy. Dysuria may occur and may require catheterization. Also, anticholinergic drugs may aggravate partial obstructive uropathy. Caution is advised even when using agents with mild to moderate anticholinergic activity, particularly in elderly patients.

The chlorpheniramine in Duravent has a moderate potential interaction with Urinary Retention.

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.

Thioridazine has a major potential interaction with Valvular Heart Disease.

Phenothiazines may cause hypotension. Patients with pheochromocytoma, cerebral vascular or renal insufficiency, cardiovascular disease, or a severe cardiac reserve deficiency (e.g., mitral insufficiency) may be more prone to hypotensive reactions. Close monitoring is recommended during treatment if used in at-risk patients; some products may be contraindicated (e.g., thioridazine). Large doses and parenteral administration should be used cautiously, or avoided, in patients with impaired cardiovascular systems.