Interactions between Dallergy and Treprostinil
1 drug interaction and 27 additional warnings found for the following 2 drugs:
- Dallergy (chlorcyclizine/phenylephrine)
- treprostinil
Drug interactions
Moderate drug interactions
Moderate:
phenylephrine treprostinil
Applies to: Dallergy (chlorcyclizine / phenylephrine) and treprostinil
Generally avoid
Concurrent administration of decongestants or vasoconstrictors may negate the vasodilatory effects of prostacyclin analogs in patients with pulmonary hypertension.
Management
The use of decongestants and vasoconstrictors should probably be avoided in patients with pulmonary hypertension. Patients should be counseled to consult with their physician before taking over-the-counter decongestants such as phenylephrine and pseudoephedrine.
References (3)
- (2001) "Product Information. Flolan (epoprostenol)." Glaxo Wellcome
- Limbird LE eds., Gilman AG, Hardman JG (1995) "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: McGraw-Hill
- (2002) "Product Information. Remodulin (treprostinil)." United Therapeutics Corporation
Food/lifestyle interactions
Moderate food/lifestyle interactions
Moderate:
chlorcyclizine Food/Lifestyle
Applies to: Dallergy (chlorcyclizine / 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: Dallergy (chlorcyclizine / 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
25 potential interactions Applies to: 18 conditions, including Asthma, Benign Prostatic Hyperplasia, COPD, Hypotension, and Hyperthyroidism.
Asthma
Moderate:
Dallergy
The chlorcyclizine in Dallergy 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:
Dallergy
The phenylephrine in Dallergy 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.
Bleeding Associated with Coagulation Defect
Moderate:
treprostinil
Treprostinil has a moderate potential interaction with Bleeding Associated with Coagulation Defect.
Treprostinil injection inhibits platelet aggregation and increases the risk of bleeding. Close monitoring is recommended when using this agent in patients with bleeding disorders.
Cardiovascular Conditions and Disorders
Major:
Dallergy
The phenylephrine in Dallergy 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:
Dallergy
The chlorcyclizine in Dallergy 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.
Cerebrovascular Insufficiency
Major:
Dallergy
The phenylephrine in Dallergy 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:
Dallergy
The chlorcyclizine in Dallergy 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.
Diabetes Mellitus
Moderate:
Dallergy
The phenylephrine in Dallergy 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.
Diverticulitis
Moderate:
treprostinil
Treprostinil has a moderate potential interaction with Diverticulitis.
The tablet shell of the manufactured form of treprostinil, Orenitram does not dissolve and can lodge in the diverticulum of patients with diverticulosis. Care should be exercised when using this drug in patient with diverticulosis.
Gastrointestinal Obstruction
Moderate:
Dallergy
The chlorcyclizine in Dallergy 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:
Dallergy
The phenylephrine in Dallergy 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:
Dallergy
The chlorcyclizine in Dallergy 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.
Hyperthyroidism
Major:
Dallergy
The phenylephrine in Dallergy 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:
Dallergy
The chlorcyclizine in Dallergy 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.
Hypotension
Moderate:
Dallergy
The chlorcyclizine in Dallergy 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.
Moderate:
treprostinil
Treprostinil has a moderate potential interaction with Hypotension.
Treprostinil is a pulmonary and systemic vasodilator. In patients with low systemic arterial pressure, treatment with treprostinil injection may produce symptomatic hypotension. Care should be exercised when using this agent in patients at risk.
Liver Disease
Major:
treprostinil
Treprostinil has a major potential interaction with Liver Disease.
The use of the extended-release tablet formulation of treprostinil is contraindicated in patients with severe hepatic impairment (Child Pugh Class C). There is a marked increase in the systemic exposure to treprostinil in hepatically impaired patients. It is recommended to start patients with mild hepatic impairment (Child Pugh Class A) at 0.125 mg BID with 0.125 mg BID dose increments every 3 to 4 days and to avoid use of treprostinil in patients with moderate hepatic impairment (Child Pugh Class B).
Moderate:
Dallergy
The chlorcyclizine in Dallergy 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.
Moderate:
treprostinil
Treprostinil has a moderate potential interaction with Liver Disease.
Severe hepatic impairment (Child Pugh Class C) is a contraindication in patients taking the oral presentation of treprostinil. Treprostinil is substantially metabolized by the liver, primarily by CYP450 2C8. Treprostinil injection clearance is reduced in patients with hepatic insufficiency. In patients with mild or moderate hepatic insufficiency, decrease the initial dose of treprostinil injection to 0.625 ng/kg/min ideal body weight, and monitor closely. Treprostinil injection has not been studied in patients with severe hepatic insufficiency. It is recommended to titrate treprostinil injection slowly in patients with hepatic insufficiency, because such patients will likely be exposed to greater systemic concentrations relative to patients with normal hepatic or renal function.
Pheochromocytoma
Major:
Dallergy
The phenylephrine in Dallergy 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.
Prostate Tumor, Benign
Moderate:
Dallergy
The phenylephrine in Dallergy 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.
Pulmonary Impairment
Moderate:
treprostinil
Treprostinil has a moderate potential interaction with Pulmonary Impairment.
The efficacy of treprostinil inhalant has not been established in patients with significant underlying lung disease. Patients with acute pulmonary infections should be carefully monitored to detect any worsening of lung disease and loss of drug effect.
Renal Dysfunction
Moderate:
Dallergy
The chlorcyclizine in Dallergy 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.
Moderate:
treprostinil
Treprostinil has a moderate potential interaction with Renal Dysfunction.
Treprostinil and its metabolites are excreted mainly through the urinary route. It is recommended to titrate treprostinil injection slowly in patients with renal insufficiency, because such patients will likely be exposed to greater systemic concentrations relative to patients with normal renal function. No dose adjustments are required in patients with renal impairment. Treprostinil is not cleared by dialysis.
Urinary Retention
Moderate:
Dallergy
The chlorcyclizine in Dallergy 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
Dallergy
A total of 456 drugs are known to interact with Dallergy.
- Dallergy is in the drug class upper respiratory combinations.
- Dallergy is used to treat the following conditions:
treprostinil
A total of 346 drugs are known to interact with treprostinil.
- Treprostinil is in the drug class agents for pulmonary hypertension.
- Treprostinil is used to treat Pulmonary Arterial Hypertension.
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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