Interactions between Acetaminophen / pheniramine / phenylephrine and Tacrine
2 drug interactions and 30 additional warnings found for the following 2 drugs:
- acetaminophen/pheniramine/phenylephrine
- tacrine
Drug interactions
Moderate drug interactions
Moderate:
acetaminophen tacrine
Applies to: acetaminophen / pheniramine / phenylephrine and tacrine
Monitor
Coadministration of acetaminophen with other potentially hepatotoxic agents may increase the risk of liver injury. The mechanism may involve additive hepatotoxic effects and, for some medicines, increased formation of hepatotoxic acetaminophen metabolites due to induction of hepatic enzymes. Therapeutic-dose acetaminophen-induced hepatotoxicity, including fatal cases, has been reported in patients with factors associated with increased hepatotoxicity risk, including concomitant use of hepatotoxic drugs, low body weight, renal or hepatic impairment, chronic alcoholism, and malnutrition or other conditions associated with glutathione depletion.
Management
Caution is advised when acetaminophen is used with other potentially hepatotoxic agents, particularly in patients with additional risk factors for hepatotoxicity. Alternative therapy may be considered when appropriate. Patients should not exceed the recommended acetaminophen dosage or use multiple acetaminophen-containing products concurrently. Patients should be monitored for clinical signs and symptoms of liver injury, and liver function monitoring may be appropriate in patients receiving prolonged or high-dose therapy or those at increased risk of hepatotoxicity. If liver injury is suspected, paracetamol should be discontinued and the patient evaluated promptly.
References (5)
- (2025) "Product Information. Anadin Paracetamol (paracetamol)." Haleon UK Trading Ltd
- (2025) "Product Information. Mersynonight (diphenhydramine-paracetamol)." Sanofi-Aventis Healthcare Pty Ltd T/A Sanofi Consumer Healthcare
- (2023) "Product Information. Acetaminophen (acetaminophen)." B. Braun of Canada Ltd
- (2026) "Product Information. Acetaminophen (acetaminophen)." Marlex Pharmaceuticals
- (2025) "Product Information. ANTIDOL INFANTIL (paracetamol)." LABORATORIOS CINFA, S.A.
Moderate:
pheniramine tacrine
Applies to: acetaminophen / pheniramine / phenylephrine and tacrine
Generally avoid
Due to opposing effects, agents that possess anticholinergic activity (e.g., sedating antihistamines; antispasmodics; neuroleptics; phenothiazines; skeletal muscle relaxants; tricyclic antidepressants; class IA antiarrhythmics especially disopyramide; carbamazepine; cimetidine; ranitidine) may negate the already small pharmacologic benefits of acetylcholinesterase inhibitors in the treatment of dementia. These agents may also adversely affect elderly patients in general. Clinically significant mental status changes associated with anticholinergic agents can range from mild cognitive impairment to delirium, and patients with Alzheimer's disease and other dementia are especially sensitive.
Management
Drugs that possess anticholinergic activity should generally be avoided in patients with Alzheimer's disease or other cognitive impairment, regardless of whether they are receiving an acetylcholinesterase inhibitor. For patients requiring treatment to counteract adverse effects of acetylcholinesterase inhibitor therapy (e.g., gastrointestinal intolerance, urinary problems), an agent without anticholinergic properties should be used whenever possible. Otherwise, a dosage reduction, slower titration, or even discontinuation of the acetylcholinesterase inhibitor should be considered. For patients who are already receiving an acetylcholinesterase inhibitor with anticholinergic agents, every attempt should be made to discontinue the latter or substitute them with less anticholinergic alternatives. Caution is required, however, since anticholinergic withdrawal may occur. Seizures have been reported following abrupt discontinuation of anticholinergics during acetylcholinesterase inhibitor therapy.
References (6)
- Beers MH, Ouslander JG, Rollingher I, Reuben DB, Brooks J, Beck JC (1991) "Explicit criteria for determining inappropriate medication use in nursing home residents." Arch Intern Med, 151, p. 1825-32
- Katz IR, Sands LP, Bilker W, DiFilippo S, Boyce A, D'Angelo K (1998) "Identification of medications that cause cognitive impairment in older people: the case of oxybutynin chloride." J Am Geriatr Soc, 46, p. 8-13
- Roe CM, Anderson MJ, Spivack B (2002) "Use of anticholinergic medications by older adults with dementia." J Am Geriatr Soc, 50, p. 836-42
- Edwards KR, O'Connor JT (2002) "Risk of delirium with concomitant use of tolterodine and acetylcholinesterase inhibitors." J Am Geriatr Soc, 50, p. 1165-6
- Fick DM, Cooper JW, Wade WE, Waller JL, Maclean JR, Beers MH (2003) "Updating the Beers criteria for potentially inappropriate medication use in older adults: results of a US consensus panel of experts." Arch Intern Med, 163, p. 2716-2724
- Carnahan RM, Lund BC, Perry PJ, Chrischilles EA (2004) "The concurrent use of anticholinergics and cholinesterase inhibitors: rare event or common practice?" J Am Geriatr Soc, 52, p. 2082-7
Food/lifestyle interactions
Major food/lifestyle interactions
Major:
acetaminophen Food/Lifestyle
Applies to: acetaminophen / pheniramine / phenylephrine
Generally avoid
Chronic, excessive consumption of alcohol may increase the risk of acetaminophen-induced hepatotoxicity, which has included rare cases of fatal hepatitis and frank hepatic failure requiring liver transplantation. The proposed mechanism is induction of hepatic microsomal enzymes during chronic alcohol use, which may result in accelerated metabolism of acetaminophen and increased production of potentially hepatotoxic metabolites.
Management
In general, chronic alcoholics should avoid regular or excessive use of acetaminophen. Alternative analgesic/antipyretic therapy may be appropriate in patients who consume three or more alcoholic drinks per day.
References (1)
- (2022) "Product Information. Acetaminophen (acetaminophen)." Camber Pharmaceuticals, Inc
Moderate food/lifestyle interactions
Moderate:
pheniramine Food/Lifestyle
Applies to: acetaminophen / pheniramine / 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: acetaminophen / pheniramine / 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
27 potential interactions Applies to: 21 conditions, including Asthma, Benign Prostatic Hyperplasia, COPD, Hypotension, and Hyperthyroidism.
Alcoholism
Major:
acetaminophen / pheniramine / phenylephrine
The acetaminophen in acetaminophen / pheniramine / phenylephrine has a major potential interaction with Alcoholism.
Chronic alcohol abusers may be at increased risk of hepatotoxicity during treatment with acetaminophen (APAP). Severe liver injury, including cases of acute liver failure resulting in liver transplant and death, has been reported in patients using acetaminophen. Therapy with acetaminophen should be administered cautiously, if at all, in patients who consume three or more alcoholic drinks a day. In general, patients should avoid drinking alcohol while taking acetaminophen-containing medications. Patients should be warned not to exceed the maximum recommended total daily dosage of acetaminophen (4 g/day in adults and children 12 years of age or older), and to read all prescription and over-the-counter medication labels to ensure they are not taking multiple acetaminophen-containing products, or check with a healthcare professional if they are unsure. They should also be advised to seek medical attention if they experience signs and symptoms of liver injury such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, and jaundice.
Asthma
Moderate:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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:
acetaminophen / pheniramine / phenylephrine
The phenylephrine in acetaminophen / pheniramine / phenylephrine 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.
Cardiovascular Conditions and Disorders
Major:
acetaminophen / pheniramine / phenylephrine
The phenylephrine in acetaminophen / pheniramine / phenylephrine 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:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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:
acetaminophen / pheniramine / phenylephrine
The phenylephrine in acetaminophen / pheniramine / phenylephrine 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:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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.
Dehydration
Major:
acetaminophen / pheniramine / phenylephrine
The acetaminophen in acetaminophen / pheniramine / phenylephrine has a major potential interaction with Dehydration.
Acetaminophen is contraindicated in patients with severe hepatic impairment or severe active liver disease. Patients with hepatic impairment may be at increased risk of toxicity. Severe liver injury, including cases of acute liver failure and death, have been reported in patients using this drug. Clinical monitoring of hepatic function is recommended. Caution is advised if using acetaminophen in patients with chronic malnutrition or severe hypovolemia. Instruct patients to avoid drinking alcohol while taking acetaminophen-containing medications. Patients should be warned not to exceed the maximum recommended total daily dosage of acetaminophen (4 g/day in adults and children 12 years of age or older), and to read all prescription and over-the-counter medication labels to ensure they are not taking multiple acetaminophen-containing products, or check with a healthcare professional if they are unsure.
Diabetes Mellitus
Moderate:
acetaminophen / pheniramine / phenylephrine
The phenylephrine in acetaminophen / pheniramine / phenylephrine 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.
Gastrointestinal Obstruction
Moderate:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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.
Moderate:
acetaminophen / pheniramine / phenylephrine
The phenylephrine in acetaminophen / pheniramine / phenylephrine 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.
Hyperthyroidism
Major:
acetaminophen / pheniramine / phenylephrine
The phenylephrine in acetaminophen / pheniramine / phenylephrine 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:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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.
Moderate:
tacrine
Tacrine has a moderate potential interaction with Hyperthyroidism.
Many of the manifestations of hyperthyroidism may be exacerbated by increased levels of acetylcholine produced by cholinesterase inhibitors. Therapy with cholinesterase inhibitors should be administered cautiously to patients with hyperthyroidism. Monitoring of thyroid levels is recommended.
Hypotension
Moderate:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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.
Ischemic Heart Disease
Major:
tacrine
Tacrine has a major potential interaction with Ischemic Heart Disease.
The use of cholinesterase inhibitors has been associated with a constriction of coronary arteries. Therapy with cholinesterase inhibitors should be administered cautiously in patients with coronary artery disease.
Liver Disease
Major:
acetaminophen / pheniramine / phenylephrine
The acetaminophen in acetaminophen / pheniramine / phenylephrine has a major potential interaction with Liver Disease.
Acetaminophen is contraindicated in patients with severe hepatic impairment or severe active liver disease. Patients with hepatic impairment may be at increased risk of toxicity. Severe liver injury, including cases of acute liver failure and death, have been reported in patients using this drug. Clinical monitoring of hepatic function is recommended. Caution is advised if using acetaminophen in patients with chronic malnutrition or severe hypovolemia. Instruct patients to avoid drinking alcohol while taking acetaminophen-containing medications. Patients should be warned not to exceed the maximum recommended total daily dosage of acetaminophen (4 g/day in adults and children 12 years of age or older), and to read all prescription and over-the-counter medication labels to ensure they are not taking multiple acetaminophen-containing products, or check with a healthcare professional if they are unsure.
Major:
tacrine
Tacrine has a major potential interaction with Liver Disease.
The use of tacrine is contraindicated in patients with a history of tacrine-induced jaundice confirmed by elevated total bilirubin greater than 3.0 mg/dl. Elevations in liver function tests (LFTs) have been reported in as many as 50% of patients receiving tacrine. Twenty-five percent of patients may experience a 3 fold rise in ALT and 7% a 10 fold rise in ALT. LFTs should be monitored prior to initiation of tacrine therapy is initiated and when dosages are altered. Tacrine undergoes extensive first-pass metabolism by the liver (CYP450-1A2) to multiple forms. The metabolic and therapeutic activity of tacrine can be altered in patients with compromised hepatic function and therapy with tacrine should be administered cautiously in these patients.
Moderate:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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.
Malnourishment
Major:
acetaminophen / pheniramine / phenylephrine
The acetaminophen in acetaminophen / pheniramine / phenylephrine has a major potential interaction with Malnourishment.
Acetaminophen is contraindicated in patients with severe hepatic impairment or severe active liver disease. Patients with hepatic impairment may be at increased risk of toxicity. Severe liver injury, including cases of acute liver failure and death, have been reported in patients using this drug. Clinical monitoring of hepatic function is recommended. Caution is advised if using acetaminophen in patients with chronic malnutrition or severe hypovolemia. Instruct patients to avoid drinking alcohol while taking acetaminophen-containing medications. Patients should be warned not to exceed the maximum recommended total daily dosage of acetaminophen (4 g/day in adults and children 12 years of age or older), and to read all prescription and over-the-counter medication labels to ensure they are not taking multiple acetaminophen-containing products, or check with a healthcare professional if they are unsure.
Parkinsonism
Major:
tacrine
Tacrine has a major potential interaction with Parkinsonism.
Cholinesterase inhibitors should be used with caution in patients with parkinsonism. Some of these drugs might be contraindicated in these patients (refer to specific prescribing information). Symptoms of Parkinson's disease may be exacerbated with the increase in cholinergic activity. Caregivers and patients should be advised.
Phenylketonuria
Moderate:
acetaminophen / pheniramine / phenylephrine
The acetaminophen in acetaminophen / pheniramine / phenylephrine has a moderate potential interaction with Phenylketonuria.
Several oral acetaminophen and acetaminophen-combination products, particularly flavored chewable tablets, contain the artificial sweetener, aspartame (NutraSweet). Aspartame is converted to phenylalanine in the gastrointestinal tract following ingestion. Chewable and effervescent formulations of acetaminophen products may also contain phenylalanine. The aspartame/phenylalanine content should be considered when these products are used in patients who must restrict their intake of phenylalanine (i.e. phenylketonurics).
Pheochromocytoma
Major:
acetaminophen / pheniramine / phenylephrine
The phenylephrine in acetaminophen / pheniramine / phenylephrine 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:
acetaminophen / pheniramine / phenylephrine
The phenylephrine in acetaminophen / pheniramine / phenylephrine 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:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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.
Urinary Retention
Moderate:
acetaminophen / pheniramine / phenylephrine
The pheniramine in acetaminophen / pheniramine / phenylephrine 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
acetaminophen / pheniramine / phenylephrine
A total of 893 drugs are known to interact with acetaminophen / pheniramine / phenylephrine.
- Acetaminophen / pheniramine / phenylephrine is in the drug class upper respiratory combinations.
- Acetaminophen / pheniramine / phenylephrine is used to treat Cold Symptoms.
tacrine
A total of 455 drugs are known to interact with tacrine.
- Tacrine is in the drug class cholinesterase inhibitors.
- Tacrine 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
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.