Interactions between Pimozide and Rondex Drops
1 drug interaction and 54 additional warnings found for the following 2 drugs:
- pimozide
- Rondex Drops (chlorpheniramine/phenylephrine)
Drug interactions
Moderate drug interactions
Moderate:
chlorpheniramine pimozide
Applies to: Rondex Drops (chlorpheniramine / phenylephrine) and pimozide
Monitor
Agents with anticholinergic properties (e.g., sedating antihistamines; antispasmodics; neuroleptics; phenothiazines; skeletal muscle relaxants; tricyclic antidepressants; disopyramide) may have additive effects when used in combination. Excessive parasympatholytic effects may result in paralytic ileus, hyperthermia, heat stroke, and the anticholinergic intoxication syndrome. Peripheral symptoms of intoxication commonly include mydriasis, blurred vision, flushed face, fever, dry skin and mucous membranes, tachycardia, urinary retention, and constipation. Central symptoms may include memory loss, disorientation, incoherence, hallucinations, psychosis, delirium, hyperactivity, twitching or jerking movements, stereotypy, and seizures. Central nervous system-depressant effects may also be additively or synergistically increased when these agents are combined, especially in elderly or debilitated patients. Use of neuroleptics in combination with other neuroleptics or anticholinergic agents may increase the risk of tardive dyskinesia. In addition, some neuroleptics and tricyclic antidepressants may cause prolongation of the QT interval and theoretically, concurrent use of two or more drugs that can cause QT interval prolongation may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death.
Management
Caution is advised when agents with anticholinergic properties are combined, particularly in the elderly and those with underlying organic brain disease, who tend to be more sensitive to the central anticholinergic effects of these drugs and in whom toxicity symptoms may be easily overlooked. Patients should be advised to notify their physician promptly if they experience potential symptoms of anticholinergic intoxication such as abdominal pain, fever, heat intolerance, blurred vision, confusion, and/or hallucinations. Ambulatory patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them. A reduction in anticholinergic dosages may be necessary if excessive adverse effects develop.
References (15)
- Stadnyk AN, Glezos JD (1983) "Drug-induced heat stroke." Can Med Assoc J, 128, p. 957-9
- Zelman S, Guillan R (1970) "Heat stroke in phenothiazine-treated patients: a report of three fatalities." Am J Psychiatry, 126, p. 1787-90
- Mann SC, Boger WP (1978) "Psychotropic drugs, summer heat and humidity, and hyperplexia: a danger restated." Am J Psychiatry, 135, p. 1097-100
- Warnes H, Lehmann HE, Ban TA (1967) "Adynamic ileus during psychoactive medication: a report of three fatal and five severe cases." Can Med Assoc J, 96, p. 1112-3
- Gershon S, Neubauer H, Sundland DM (1965) "Interaction between some anticholinergic agents and phenothiazines." Clin Pharmacol Ther, 6, p. 749-56
- Sarnquist F, Larson CP Jr (1973) "Drug-induced heat stroke." Anesthesiology, 39, p. 348-50
- Johnson AL, Hollister LE, Berger PA (1981) "The anticholinergic intoxication syndrome: diagnosis and treatment." J Clin Psychiatry, 42, p. 313-7
- Lee BS (1986) "Possibility of hyperpyrexia with antipsychotic and anticholinergic drugs." J Clin Psychiatry, 47, p. 571
- Forester D (1978) "Fatal drug-induced heat stroke." JACEP, 7, p. 243-4
- Moreau A, Jones BD, Banno V (1986) "Chronic central anticholinergic toxicity in manic depressive illness mimicking dementia." Can J Psychiatry, 31, p. 339-41
- Hvizdos AJ, Bennett JA, Wells BG, Rappaport KB, Mendel SA (1983) "Anticholinergic psychosis in a patient receiving usual doses of haloperidol." Clin Pharm, 2, p. 174-8
- Cohen MA, Alfonso CA, Mosquera M (1994) "Development of urinary retention during treatment with clozapine and meclizine [published erratum appears in Am J Psychiatry 1994 Jun;151(6):952]." Am J Psychiatry, 151, p. 619-20
- (2001) "Product Information. Cogentin (benztropine)." Merck & Co., Inc
- Kulik AV, Wilbur R (1982) "Delirium and stereotypy from anticholinergic antiparkinson drugs." Prog Neuropsychopharmacol Biol Psychiatry, 6, p. 75-82
- (2001) "Product Information. Artane (trihexyphenidyl)." Lederle Laboratories
Food/lifestyle interactions
Major food/lifestyle interactions
Major:
pimozide Food/Lifestyle
Applies to: pimozide
Generally avoid
Theoretically, the coadministration with grapefruit juice may increase the plasma concentrations of pimozide. The mechanism is decreased clearance of pimozide due to inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. The use of pimozide alone has been associated with dose-dependent prolongation of the QT interval. Although clinical data are lacking, this interaction may result in potentiation of the proarrhythmic effect of pimozide and consequently an increased risk of ventricular arrhythmias such as ventricular tachycardia and torsade de pointes. In addition, alcohol may potentiate some of the pharmacologic effects of pimozide. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.
Management
The manufacturer recommends avoiding grapefruit juice (and probably grapefruits) during therapy with pimozide. Patients should also be advised to avoid or limit consumption of alcohol.
References (2)
- "Product Information. Orap (pimozide)." Gate Pharmaceuticals
- Dresser GK, Spence JD, Bailey DG (2000) "Pharmacokinetic-pharmacodynamic consequences and clinical relevance of cytochrome P450 3A4 inhibition." Clin Pharmacokinet, 38, p. 41-57
Moderate food/lifestyle interactions
Moderate:
chlorpheniramine Food/Lifestyle
Applies to: Rondex Drops (chlorpheniramine / phenylephrine)
Generally avoid
Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.
Management
Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
References (4)
- Warrington SJ, Ankier SI, Turner P (1986) "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology, 15, p. 31-7
- Gilman AG, eds., Nies AS, Rall TW, Taylor P (1990) "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc.
- (2012) "Product Information. Fycompa (perampanel)." Eisai Inc
- (2015) "Product Information. Rexulti (brexpiprazole)." Otsuka America Pharmaceutical, Inc.
Moderate:
phenylephrine Caffeine
Applies to: Rondex Drops (chlorpheniramine / phenylephrine)
Monitor
Coadministration of two or more sympathomimetic or noradrenergic agents may increase the risk of nervousness, irritability, tachycardia, and/or increased blood pressure. Central nervous system (CNS) stimulants, particularly amphetamines, can potentiate the adrenergic response to vasopressors and other sympathomimetic and/or noradrenergic agents, including norepinephrine transporter inhibitors. Additive increases in blood pressure and heart rate may occur due to enhanced peripheral sympathetic activity.
Management
Caution is advised if two or more sympathomimetic or noradrenergic agents are coadministered. Pulse and blood pressure should be closely monitored. Consultation with individual product labeling, as well as relevant institutional protocols, may be advisable for further guidance.
References (20)
- Rosenblatt JE, Lake CR, van Kammen DP, Ziegler MG, Bunney WE Jr (1979) "Interactions of amphetamine, pimozide, and lithium on plasma norepineophrine and dopamine-beta-hydroxylase in schizophrenic patients." Psychiatry Res, 1, p. 45-52
- Cavanaugh JH, Griffith JD, Oates JA (1970) "Effect of amphetamine on the pressor response to tyramine: formation of p-hydroxynorephedrine from amphetamine in man." Clin Pharmacol Ther, 11, p. 656
- (2001) "Product Information. Adderall (amphetamine-dextroamphetamine)." Shire Richwood Pharmaceutical Company Inc
- (2001) "Product Information. Tenuate (diethylpropion)." Aventis Pharmaceuticals
- (2001) "Product Information. Sanorex (mazindol)." Novartis Pharmaceuticals
- (2001) "Product Information. Focalin (dexmethylphenidate)." Mikart Inc
- (2024) "Product Information. Ephedrine (ephedrine)." Hameln Pharma Ltd
- (2023) "Product Information. Ephedrine Hydrochloride (ephedrine)." Wockhardt UK Ltd
- (2026) "Product Information. Strattera (atomoxetine)." Lilly, Eli and Company
- (2025) "Product Information. Atomoxetine (atomoxetine)." Zentiva Pharma UK Ltd
- (2026) "Product Information. Atomoxetine (Apo) (atomoxetine)." Arrotex Pharmaceuticals Pty Ltd
- Angita Pharma, Inc (2026) AG-ATOMOXETINE Product Monograph (Health Canada) https://pdf.hres.ca/dpd_pm/00059014.PDF
- (2026) "Product Information. Boots Decongestant (Pseudoephedrine) (pseudoephedrine)." The Boots Company Plc
- (2023) "Product Information. Sinus and Nasal Decongestant (Trust) (pseudoephedrine)." Noumed Pharmaceuticals Pty Ltd
- (2019) "Product Information. Ephedrine (ephedrine)." Pfizer Australia Pty Ltd
- (2024) "Product Information. EPHEDrine Sulfate (ePHEDrine)." Amneal Pharmaceuticals LLC
- (2024) "Product Information. Lemsip Cough Max for Mucus Cough and Cold (guaifenesin/paracetamol/phenylephrine)." Reckitt Benckiser Healthcare (UK) Ltd
- emc (2026) Product information: sudafed plus blocked nose 1mg/50mg/ml nasal spray. https://www.medicines.org.uk/emc/product/14256/smpc?utm_source=chatgpt.com
- (2023) "Product Information. EPHEDrine Sulfate (ePHEDrine)." Baxter Corporation
- Neo Health (OTC) Pty Ltd (2026) Product information: pseudoephedrine hydrochloride-paracetamol capsules. https://www.ebs.tga.gov.au/ebs/picmi/picmirepository.nsf/pdf?OpenAgent&id=CP-2024-PI-02603-1&d=20260804172310101&d=20260827172310101
Disease interactions
51 potential interactions Applies to: 37 conditions, including Asthma, Benign Prostatic Hyperplasia, COPD, Seizures, and Diarrhea.
Abnormal Electrocardiogram
Major:
pimozide
Pimozide has a major potential interaction with Abnormal Electrocardiogram.
The use of pimozide is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Pimozide can prolong the QT interval of the electrocardiogram. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of pimozide on the QT interval and should be corrected prior to institution of pimozide 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 pimozide. Because sudden deaths have been reported in patients using pimozide, and electrocardiogram should be performed before starting treatment and periodically thereafter, especially during periods of dose adjustment.
Acute Alcohol Intoxication
Major:
pimozide
Pimozide has a major potential interaction with Acute Alcohol Intoxication.
The use of most miscellaneous antipsychotics is contraindicated in patients with severe central nervous system depression or comatose states from any cause (e.g., lesion, disease, drug or alcohol induced).
Alcoholism
Major:
pimozide
Pimozide has a major potential interaction with Alcoholism.
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.
Major:
pimozide
Pimozide has a major potential interaction with Alcoholism.
Antipsychotics can lower the seizure threshold and trigger seizures in a dose-dependent manner. Seizures have been reported in patients receiving antipsychotic therapy and may occur in epileptic patients even with maintenance of routine anticonvulsant treatment. Therapy with antipsychotics should be administered cautiously in patients with a history of seizures or other predisposing factors, such as head trauma, CNS abnormalities, and alcoholism. High dosages should be avoided if possible.
Moderate:
pimozide
Pimozide has a moderate potential interaction with Alcoholism.
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.
Altered Consciousness
Major:
pimozide
Pimozide has a major potential interaction with Altered Consciousness.
The use of most miscellaneous antipsychotics is contraindicated in patients with severe central nervous system depression or comatose states from any cause (e.g., lesion, disease, drug or alcohol induced).
Major:
pimozide
Pimozide has a major potential interaction with Altered Consciousness.
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.
Arrhythmia
Major:
pimozide
Pimozide has a major potential interaction with Arrhythmia.
The use of pimozide is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Pimozide can prolong the QT interval of the electrocardiogram. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of pimozide on the QT interval and should be corrected prior to institution of pimozide 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 pimozide. Because sudden deaths have been reported in patients using pimozide, and electrocardiogram should be performed before starting treatment and periodically thereafter, especially during periods of dose adjustment.
Asthma
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Benign Prostatic Hyperplasia
Moderate:
Rondex Drops
The phenylephrine in Rondex Drops 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.
Breast Cancer
Moderate:
pimozide
Pimozide has a moderate potential interaction with Breast Cancer.
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.
Moderate:
pimozide
Pimozide has a moderate potential interaction with Breast Cancer.
Antipsychotic drugs can elevate serum prolactin concentrations, and this elevation persists during chronic administration. This should be considered if therapy will be prescribed in patients with previously detected breast cancer as one-third of human breast cancers are prolactin-dependent in vitro. Associated disturbances such as galactorrhea, amenorrhea, gynecomastia, and impotence have been reported. Appropriate laboratory testing and follow-up is advised.
Cardiovascular Conditions and Disorders
Major:
Rondex Drops
The phenylephrine in Rondex Drops 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.
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Central Nervous System Disorders
Major:
pimozide
Pimozide has a major potential interaction with Central Nervous System Disorders.
Antipsychotics can lower the seizure threshold and trigger seizures in a dose-dependent manner. Seizures have been reported in patients receiving antipsychotic therapy and may occur in epileptic patients even with maintenance of routine anticonvulsant treatment. Therapy with antipsychotics should be administered cautiously in patients with a history of seizures or other predisposing factors, such as head trauma, CNS abnormalities, and alcoholism. High dosages should be avoided if possible.
Cerebrovascular Insufficiency
Major:
Rondex Drops
The phenylephrine in Rondex Drops 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.
COPD
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Dementia
Major:
pimozide
Pimozide 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.
Diabetes Mellitus
Moderate:
Rondex Drops
The phenylephrine in Rondex Drops 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.
Diarrhea
Major:
pimozide
Pimozide has a major potential interaction with Diarrhea.
The use of pimozide is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Pimozide can prolong the QT interval of the electrocardiogram. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of pimozide on the QT interval and should be corrected prior to institution of pimozide 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 pimozide. Because sudden deaths have been reported in patients using pimozide, and electrocardiogram should be performed before starting treatment and periodically thereafter, especially during periods of dose adjustment.
Electrolyte Abnormalities
Major:
pimozide
Pimozide has a major potential interaction with Electrolyte Abnormalities.
The use of pimozide is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Pimozide can prolong the QT interval of the electrocardiogram. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of pimozide on the QT interval and should be corrected prior to institution of pimozide 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 pimozide. Because sudden deaths have been reported in patients using pimozide, and electrocardiogram should be performed before starting treatment and periodically thereafter, especially during periods of dose adjustment.
Gastrointestinal Obstruction
Moderate:
pimozide
Pimozide has a moderate potential interaction with Gastrointestinal Obstruction.
Most neuroleptic agents have anticholinergic activity, to which elderly patients are particularly sensitive. Clozapine and low- potency agents such as chlorpromazine and thioridazine tend to exhibit the greatest degree of anticholinergic effects in the class, while haloperidol as well as the newer, atypical agents like quetiapine, risperidone and ziprasidone have generally been associated with very low frequencies of anticholinergic adverse effects. Therapy with neuroleptic agents should be administered cautiously 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.
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Glaucoma/Intraocular Hypertension
Moderate:
pimozide
Pimozide has a moderate potential interaction with Glaucoma/Intraocular Hypertension.
Most neuroleptic agents have anticholinergic activity, to which elderly patients are particularly sensitive. Clozapine and low- potency agents such as chlorpromazine and thioridazine tend to exhibit the greatest degree of anticholinergic effects in the class, while haloperidol as well as the newer, atypical agents like quetiapine, risperidone and ziprasidone have generally been associated with very low frequencies of anticholinergic adverse effects. Therapy with neuroleptic agents should be administered cautiously 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.
Moderate:
Rondex Drops
The phenylephrine in Rondex Drops 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.
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Head Injury
Moderate:
pimozide
Pimozide has a moderate potential interaction with Head Injury.
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.
Hyperprolactinemia
Moderate:
pimozide
Pimozide has a moderate potential interaction with Hyperprolactinemia.
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.
Moderate:
pimozide
Pimozide has a moderate potential interaction with Hyperprolactinemia.
Antipsychotic drugs can elevate serum prolactin concentrations, and this elevation persists during chronic administration. This should be considered if therapy will be prescribed in patients with previously detected breast cancer as one-third of human breast cancers are prolactin-dependent in vitro. Associated disturbances such as galactorrhea, amenorrhea, gynecomastia, and impotence have been reported. Appropriate laboratory testing and follow-up is advised.
Hyperthyroidism
Major:
Rondex Drops
The phenylephrine in Rondex Drops 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.
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Hypokalemia
Major:
pimozide
Pimozide has a major potential interaction with Hypokalemia.
The use of pimozide is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Pimozide can prolong the QT interval of the electrocardiogram. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of pimozide on the QT interval and should be corrected prior to institution of pimozide 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 pimozide. Because sudden deaths have been reported in patients using pimozide, and electrocardiogram should be performed before starting treatment and periodically thereafter, especially during periods of dose adjustment.
Hypotension
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Liver Disease
Moderate:
pimozide
Pimozide has a moderate potential interaction with Liver Disease.
Pimozide is extensively metabolized by the liver, and both parent drug and metabolites are eliminated by the kidney. Patients with impaired renal and/or hepatic function may be at greater risk for adverse effects due to drug and metabolite accumulation. Therapy with pimozide should be administered cautiously in such patients.
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Magnesium Imbalance
Major:
pimozide
Pimozide has a major potential interaction with Magnesium Imbalance.
The use of pimozide is contraindicated in patients with congenital or acquired QT interval prolongation syndromes or a history of cardiac arrhythmias. Pimozide can prolong the QT interval of the electrocardiogram. The risk of torsade de pointes is progressively increased as the degree of prolongation becomes greater. Electrolyte disturbances such as hypokalemia and hypomagnesemia may augment the prolongation effect of pimozide on the QT interval and should be corrected prior to institution of pimozide 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 pimozide. Because sudden deaths have been reported in patients using pimozide, and electrocardiogram should be performed before starting treatment and periodically thereafter, especially during periods of dose adjustment.
Neuroleptic Malignant Syndrome
Major:
pimozide
Pimozide has a major potential interaction with Neuroleptic Malignant 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.
Major:
pimozide
Pimozide has a major potential interaction with Neuroleptic Malignant Syndrome.
Neuroleptic Malignant Syndrome (NMS), a potentially fatal symptom complex, has been reported in association with the use of antipsychotic drugs. The diagnostic evaluation is complicated and the management requires immediate discontinuation of the antipsychotic therapy and intensive symptomatic treatment and medical monitoring. If a patient that has recovered from NMS requires antipsychotic drug treatment again, the reintroduction of therapy should be carefully considered as NMS recurrences have been reported.
Neutropenia
Moderate:
pimozide
Pimozide has a moderate potential interaction with Neutropenia.
The use of antipsychotics has been associated with events of leukopenia, neutropenia and agranulocytosis. Possible risk factors include preexisting low white blood cell count, and history of drug induced leukopenia/neutropenia. Patients with these risk factors should have complete blood count monitored frequently during the first few months of therapy. Patients should also be monitored for any signs or symptoms of infection. Treatment should be discontinued in any patient who develops a sore throat, fever, stomatitis, or other signs of infection along with a low WBC count or severe neutropenia (ANC < 1000/mm3).
Parkinsonism
Moderate:
pimozide
Pimozide has a moderate potential interaction with Parkinsonism.
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.
Pheochromocytoma
Major:
Rondex Drops
The phenylephrine in Rondex Drops 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.
Pituitary Tumor
Major:
pimozide
Pimozide has a major potential interaction with Pituitary Tumor.
Pimozide may have a tumorigenic potential and has been shown to cause a dose-related increase in pituitary tumors in mice. When treated for up to 18 months, pituitary gland changes that occurred were characterized as hyperplasia at doses approximating the human dose and adenoma at doses about 15 times the maximum recommended human dose on a mg/kg basis. The full significance of this finding is unknown but should be considered when prescribing pimozide, particularly in patients with preexisting pituitary tumors.
Prostate Tumor, Benign
Moderate:
Rondex Drops
The phenylephrine in Rondex Drops 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.
Renal Dysfunction
Moderate:
pimozide
Pimozide has a moderate potential interaction with Renal Dysfunction.
Pimozide is extensively metabolized by the liver, and both parent drug and metabolites are eliminated by the kidney. Patients with impaired renal and/or hepatic function may be at greater risk for adverse effects due to drug and metabolite accumulation. Therapy with pimozide should be administered cautiously in such patients.
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
Respiratory Arrest
Major:
pimozide
Pimozide has a major potential interaction with Respiratory Arrest.
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.
Seizures
Moderate:
pimozide
Pimozide has a moderate potential interaction with Seizures.
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.
Tardive Dyskinesia
Moderate:
pimozide
Pimozide has a moderate potential interaction with Tardive Dyskinesia.
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.
Tic Disorder
Major:
pimozide
Pimozide has a major potential interaction with Tic Disorder.
Pimozide is contraindicated in the treatment of simple tics or tics other than those associated with Tourette's Disorder.
Urinary Retention
Moderate:
pimozide
Pimozide has a moderate potential interaction with Urinary Retention.
Most neuroleptic agents have anticholinergic activity, to which elderly patients are particularly sensitive. Clozapine and low- potency agents such as chlorpromazine and thioridazine tend to exhibit the greatest degree of anticholinergic effects in the class, while haloperidol as well as the newer, atypical agents like quetiapine, risperidone and ziprasidone have generally been associated with very low frequencies of anticholinergic adverse effects. Therapy with neuroleptic agents should be administered cautiously 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.
Moderate:
Rondex Drops
The chlorpheniramine in Rondex Drops 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.
More resources
pimozide
A total of 776 drugs are known to interact with pimozide.
- Pimozide is in the drug class miscellaneous antipsychotic agents.
- Pimozide is used to treat Tourette's Syndrome.
Rondex Drops
A total of 531 drugs are known to interact with Rondex Drops.
- Rondex drops is in the drug class upper respiratory combinations.
- Rondex drops is used to treat the following conditions:
Drug Interaction Classification
| Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
| Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
| Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. | |
| No interaction information available. |
Further information
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