Hyoscyamine, methenamine, methylene blue, and sodium phosphate: Drug information

Drug Interactions

Acetylcholinesterase Inhibitors: May diminish the therapeutic effect of Anticholinergic Agents. Anticholinergic Agents may diminish the therapeutic effect of Acetylcholinesterase Inhibitors. Risk C: Monitor therapy

Aclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Risk X: Avoid combination

Agents with Blood Glucose Lowering Effects: Monoamine Oxidase Inhibitors may enhance the hypoglycemic effect of Agents with Blood Glucose Lowering Effects. Risk C: Monitor therapy

Alcohol (Ethyl): May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Alosetron: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Alpha-/Beta-Agonists (Indirect-Acting): Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Alpha-/Beta-Agonists (Indirect-Acting). While linezolid is expected to interact via this mechanism, management recommendations differ from other monoamine oxidase inhibitors. Refer to linezolid specific monographs for details. Risk X: Avoid combination

Alpha1-Agonists: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Alpha1-Agonists. While linezolid is expected to interact via this mechanism, management recommendations differ from other monoamine oxidase inhibitors. Refer to linezolid specific monographs for details. Risk X: Avoid combination

Amantadine: May enhance the anticholinergic effect of Anticholinergic Agents. Risk C: Monitor therapy

Amantadine: Urinary Acidifying Agents may decrease the serum concentration of Amantadine. Risk C: Monitor therapy

Amifampridine: Agents With Seizure Threshold Lowering Potential may enhance the neuroexcitatory and/or seizure-potentiating effect of Amifampridine. Risk C: Monitor therapy

Amisulpride (Oral): Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Amisulpride (Oral). Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Amphetamines: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Amphetamines. While linezolid and tedizolid may interact via this mechanism, management recommendations differ from other monoamine oxidase inhibitors. Refer to monographs specific to those agents for details. Risk X: Avoid combination

Antacids: May diminish the therapeutic effect of Methenamine. Management: Consider avoiding the concomitant use of medications that alkalinize the urine, such as antacids, and methenamine. Monitor for decreased therapeutic effects of methenamine if used concomitant with antacids. Risk D: Consider therapy modification

Antacids: May decrease the serum concentration of Hyoscyamine. Management: Administer immediate release and sublingual oral hyoscyamine before meals, and antacids after meals, when these agents are given in combination. Risk D: Consider therapy modification

Anticholinergic Agents: May enhance the adverse/toxic effect of other Anticholinergic Agents. Risk C: Monitor therapy

Antiemetics (5HT3 Antagonists): May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Apraclonidine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Apraclonidine. Monoamine Oxidase Inhibitors may increase the serum concentration of Apraclonidine. Risk X: Avoid combination

ARIPiprazole: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of ARIPiprazole. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

ARIPiprazole Lauroxil: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of ARIPiprazole Lauroxil. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Asenapine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Asenapine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Atomoxetine: Monoamine Oxidase Inhibitors may enhance the neurotoxic (central) effect of Atomoxetine. Risk X: Avoid combination

Atropine (Ophthalmic): Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Atropine (Ophthalmic). Risk X: Avoid combination

Bacillus clausii: Antibiotics may diminish the therapeutic effect of Bacillus clausii. Management: Bacillus clausii should be taken in between antibiotic doses during concomitant therapy. Risk D: Consider therapy modification

BCG (Intravesical): Antibiotics may diminish the therapeutic effect of BCG (Intravesical). Risk X: Avoid combination

BCG Vaccine (Immunization): Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization). Risk C: Monitor therapy

Benperidol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Benperidol. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Benzhydrocodone: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Management: The use of benzhydrocodone is not recommended for patients taking monoamine oxidase inhibitors (MAOIs) or within 14 days of MAOI discontinuation. If coadministration is required, use test doses and frequent titration of small benzhydrocodone. Risk D: Consider therapy modification

Beta2-Agonists: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Beta2-Agonists. Risk C: Monitor therapy

Betahistine: Monoamine Oxidase Inhibitors may increase the serum concentration of Betahistine. Risk C: Monitor therapy

Bezafibrate: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Bezafibrate. Risk X: Avoid combination

Blonanserin: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Blonanserin. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Botulinum Toxin-Containing Products: May enhance the anticholinergic effect of Anticholinergic Agents. Risk C: Monitor therapy

Brexpiprazole: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Brexpiprazole. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Brimonidine (Ophthalmic): Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Brimonidine (Ophthalmic). Monoamine Oxidase Inhibitors may increase the serum concentration of Brimonidine (Ophthalmic). Risk C: Monitor therapy

Brimonidine (Topical): Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Brimonidine (Topical). Monoamine Oxidase Inhibitors may increase the serum concentration of Brimonidine (Topical). Risk C: Monitor therapy

Bromperidol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Bromperidol. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Buprenorphine: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

BuPROPion: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of BuPROPion. Risk X: Avoid combination

BusPIRone: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Butorphanol: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Risk X: Avoid combination

Cannabinoid-Containing Products: Anticholinergic Agents may enhance the tachycardic effect of Cannabinoid-Containing Products. Risk C: Monitor therapy

CarBAMazepine: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Management: Do not use carbamazepine during, or within 14 days of discontinuing, treatment with a monoamine oxidase inhibitor. Risk X: Avoid combination

Carbinoxamine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Carbinoxamine. Specifically, the anticholinergic effects of carbinoxamine may be enhanced and prolonged. Risk X: Avoid combination

Carbonic Anhydrase Inhibitors: May diminish the therapeutic effect of Methenamine. Management: Consider avoiding the concomitant use of medications that alkalinize the urine, such as carbonic anhydrase inhibitors, and methenamine. Monitor for decreased therapeutic effects of methenamine if used concomitant with a carbonic anhydrase inhibitor. Risk D: Consider therapy modification

Cariprazine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Cariprazine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Cerebrolysin: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk C: Monitor therapy

Chloral Betaine: May enhance the adverse/toxic effect of Anticholinergic Agents. Risk C: Monitor therapy

Chlorphenesin Carbamate: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk C: Monitor therapy

ChlorproMAZINE: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of ChlorproMAZINE. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

ChlorproPAMIDE: Urinary Acidifying Agents may increase the serum concentration of ChlorproPAMIDE. Risk C: Monitor therapy

Chlorprothixene: Anticholinergic Agents may enhance the anticholinergic effect of Chlorprothixene. Risk C: Monitor therapy

Cholera Vaccine: Antibiotics may diminish the therapeutic effect of Cholera Vaccine. Management: Avoid cholera vaccine in patients receiving systemic antibiotics, and within 14 days following the use of oral or parenteral antibiotics. Risk X: Avoid combination

Cimetropium: Anticholinergic Agents may enhance the anticholinergic effect of Cimetropium. Risk X: Avoid combination

Clemastine: Monoamine Oxidase Inhibitors may enhance the anticholinergic effect of Clemastine. Risk C: Monitor therapy

Clothiapine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Clothiapine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

CloZAPine: Anticholinergic Agents may enhance the constipating effect of CloZAPine. Management: Consider alternatives to this combination whenever possible. If combined, monitor closely for signs and symptoms of gastrointestinal hypomotility and consider prophylactic laxative treatment. Risk D: Consider therapy modification

Cocaine (Topical): May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk C: Monitor therapy

Codeine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Codeine. Risk X: Avoid combination

COMT Inhibitors: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Management: Avoid coadministration of COMT inhibitors and nonselective monoamine oxidase inhibitors (MAOIs) (eg, isocarboxazid, phenelzine, tranylcypromine, linezolid, methylene blue) whenever possible. Risk D: Consider therapy modification

Cyclobenzaprine: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Risk X: Avoid combination

Cyproheptadine: Monoamine Oxidase Inhibitors may enhance the anticholinergic effect of Cyproheptadine. Cyproheptadine may diminish the serotonergic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Dapoxetine: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Do not use serotonergic agents (high risk) with dapoxetine or within 7 days of serotonergic agent discontinuation. Do not use dapoxetine within 14 days of monoamine oxidase inhibitor use. Dapoxetine labeling lists this combination as contraindicated. Risk X: Avoid combination

Deutetrabenazine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Deutetrabenazine. Risk X: Avoid combination

Dexmethylphenidate: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Dexmethylphenidate. Risk X: Avoid combination

Dextromethorphan: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This may cause serotonin syndrome. Risk X: Avoid combination

Diamorphine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Diamorphine. Risk X: Avoid combination

Diethylpropion: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Diethylpropion. Risk X: Avoid combination

Dihydrocodeine: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Management: Consider avoiding use of dihydrocodeine while the patient is taking monoamine oxidase inhibitors (MAOIs) and for 2 weeks after MAOI discontinuation. Risk D: Consider therapy modification

Diphenoxylate: May enhance the hypertensive effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Domperidone: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Domperidone. Monoamine Oxidase Inhibitors may diminish the therapeutic effect of Domperidone. Domperidone may diminish the therapeutic effect of Monoamine Oxidase Inhibitors. Risk C: Monitor therapy

DOPamine: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of DOPamine. Management: Initiate dopamine at no greater than one-tenth (1/10) of the usual dose in patients who are taking (or have taken within the last 2 to 3 weeks) monoamine oxidase inhibitors. Monitor for an exaggerated hypertensive response to dopamine. Risk D: Consider therapy modification

Doxapram: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Doxapram. Risk C: Monitor therapy

Doxylamine: Monoamine Oxidase Inhibitors may enhance the anticholinergic effect of Doxylamine. Risk X: Avoid combination

DroPERidol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of DroPERidol. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Droxidopa: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Droxidopa. Risk X: Avoid combination

Eluxadoline: Anticholinergic Agents may enhance the constipating effect of Eluxadoline. Risk X: Avoid combination

EPINEPHrine (Nasal): Monoamine Oxidase Inhibitors may enhance the hypertensive effect of EPINEPHrine (Nasal). Risk C: Monitor therapy

EPINEPHrine (Oral Inhalation): Monoamine Oxidase Inhibitors may enhance the hypertensive effect of EPINEPHrine (Oral Inhalation). Risk X: Avoid combination

Epinephrine (Racemic): Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Epinephrine (Racemic). Risk C: Monitor therapy

EPINEPHrine (Systemic): Monoamine Oxidase Inhibitors may enhance the hypertensive effect of EPINEPHrine (Systemic). Risk C: Monitor therapy

Ergot Derivatives: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Esketamine: May enhance the hypertensive effect of Monoamine Oxidase Inhibitors. Risk C: Monitor therapy

Fecal Microbiota (Live) (Oral): May diminish the therapeutic effect of Antibiotics. Risk X: Avoid combination

Fecal Microbiota (Live) (Rectal): Antibiotics may diminish the therapeutic effect of Fecal Microbiota (Live) (Rectal). Risk X: Avoid combination

Fenfluramine: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Flupentixol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Flupentixol. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

FluPHENAZine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of FluPHENAZine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Gastrointestinal Agents (Prokinetic): Anticholinergic Agents may diminish the therapeutic effect of Gastrointestinal Agents (Prokinetic). Risk C: Monitor therapy

Gepirone: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Glucagon: Anticholinergic Agents may enhance the adverse/toxic effect of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Risk C: Monitor therapy

Glycopyrrolate (Oral Inhalation): Anticholinergic Agents may enhance the anticholinergic effect of Glycopyrrolate (Oral Inhalation). Risk X: Avoid combination

Glycopyrronium (Topical): May enhance the anticholinergic effect of Anticholinergic Agents. Risk X: Avoid combination

Guanethidine: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Haloperidol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Haloperidol. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

HYDROcodone: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of HYDROcodone. HYDROcodone may enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Management: Consider alternatives to this combination when possible. If coadministration is required, use test doses, titrate small doses frequently, and monitor patients closely for evidence of serotonergic and opioid toxicities. Risk D: Consider therapy modification

HYDROmorphone: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of HYDROmorphone. Management: Coadministration of hydromorphone and monoamine oxidase (MAO) inhibitors (or within 14 days of stopping an MAO inhibitor) is not recommended. If required, use test doses, titrate small doses frequently, and monitor for CNS and respitatory depression. Risk D: Consider therapy modification

Iloperidone: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Iloperidone. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Immune Checkpoint Inhibitors (Anti-PD-1, -PD-L1, and -CTLA4 Therapies): Antibiotics may diminish the therapeutic effect of Immune Checkpoint Inhibitors (Anti-PD-1, -PD-L1, and -CTLA4 Therapies). Risk C: Monitor therapy

Indoramin: Monoamine Oxidase Inhibitors may enhance the hypotensive effect of Indoramin. Risk X: Avoid combination

Iobenguane Radiopharmaceutical Products: Monoamine Oxidase Inhibitors may diminish the therapeutic effect of Iobenguane Radiopharmaceutical Products. Management: Discontinue all drugs that may inhibit or interfere with catecholamine transport or uptake for at least 5 biological half-lives before iobenguane administration. Do not administer these drugs until at least 7 days after each iobenguane dose. Risk X: Avoid combination

Iohexol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Iohexol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iohexol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic antiseizure drugs. Risk D: Consider therapy modification

Iomeprol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Iomeprol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iomeprol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic antiseizure drugs. Risk D: Consider therapy modification

Iopamidol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Iopamidol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iopamidol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic antiseizure drugs. Risk D: Consider therapy modification

Ipratropium (Oral Inhalation): May enhance the anticholinergic effect of Anticholinergic Agents. Risk X: Avoid combination

Isometheptene: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Isometheptene. Risk X: Avoid combination

Isoproterenol: Monoamine Oxidase Inhibitors may enhance the therapeutic effect of Isoproterenol. Risk C: Monitor therapy

Itopride: Anticholinergic Agents may diminish the therapeutic effect of Itopride. Risk C: Monitor therapy

Ketoconazole (Systemic): Hyoscyamine may decrease the serum concentration of Ketoconazole (Systemic). Management: Take hyoscyamine at least 2 hours after ingestion of ketoconazole. Monitor for decreased therapeutic effects of ketoconazole if used together with hyoscyamine. Risk D: Consider therapy modification

Lactobacillus and Estriol: Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol. Risk C: Monitor therapy

Lasmiditan: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Levodopa-Foslevodopa: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Of particular concern is the development of hypertensive reactions when levodopa is used with nonselective MAOI. Risk X: Avoid combination

Levomethadone: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Levonordefrin: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Levonordefrin. Risk X: Avoid combination

Levosulpiride: Anticholinergic Agents may diminish the therapeutic effect of Levosulpiride. Risk X: Avoid combination

Linezolid: Methylene Blue may enhance the serotonergic effect of Linezolid. This could result in serotonin syndrome. Risk X: Avoid combination

Lithium: Methylene Blue may enhance the serotonergic effect of Lithium. This could result in serotonin syndrome. Management: Consider alternatives to this drug combination. If combined, monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes). Risk D: Consider therapy modification

Lorcaserin (Withdrawn From US Market): May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Loxapine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Loxapine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Lumateperone: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Lumateperone. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Lurasidone: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Lurasidone. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Maprotiline: May enhance the hypertensive effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Mecamylamine: Urinary Acidifying Agents may decrease the serum concentration of Mecamylamine. Risk C: Monitor therapy

Meptazinol: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Meptazinol. Risk X: Avoid combination

Mequitazine: Monoamine Oxidase Inhibitors may enhance the anticholinergic effect of Mequitazine. Risk X: Avoid combination

Metaraminol: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Metaraminol. Risk C: Monitor therapy

Metaxalone: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Methadone: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Risk X: Avoid combination

Methotrimeprazine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Methotrimeprazine. Specifically, monoamine oxidase inhibitors may enhance dopamine blockade, possible increasing the risk for neuroleptic malignant syndrome. Methotrimeprazine may enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Risk X: Avoid combination

Methoxsalen (Systemic): Methylene Blue may enhance the photosensitizing effect of Methoxsalen (Systemic). Risk C: Monitor therapy

Methyldopa: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Methyldopa. Risk X: Avoid combination

Methylphenidate: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Methylphenidate. Risk X: Avoid combination

Metoclopramide: May enhance the hypertensive effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Mianserin: Monoamine Oxidase Inhibitors may enhance the neurotoxic effect of Mianserin. Risk X: Avoid combination

Mirabegron: Anticholinergic Agents may enhance the adverse/toxic effect of Mirabegron. Risk C: Monitor therapy

Mivacurium: Monoamine Oxidase Inhibitors may increase the serum concentration of Mivacurium. Risk C: Monitor therapy

Molindone: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Molindone. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Monoamine Oxidase Inhibitors (Antidepressant): May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Monoamine Oxidase Inhibitors (Type B): May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Morphine (Systemic): Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Morphine (Systemic). Risk X: Avoid combination

Nalbuphine: Monoamine Oxidase Inhibitors may enhance the CNS depressant effect of Nalbuphine. Nalbuphine may enhance the hypertensive effect of Monoamine Oxidase Inhibitors. Nalbuphine may enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Management: Use of nalbuphine is not recommended in patients taking MAOIs, or within 14 days of stopping MAOI therapy. If urgent nalbuphine use is needed, use test doses and frequent titration while monitoring blood pressure, CNS depression, and serotonergic toxicity Risk D: Consider therapy modification

Nefazodone: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Nefopam: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Nefopam. Risk X: Avoid combination

Nitroglycerin: Anticholinergic Agents may decrease the absorption of Nitroglycerin. Specifically, anticholinergic agents may decrease the dissolution of sublingual nitroglycerin tablets, possibly impairing or slowing nitroglycerin absorption. Risk C: Monitor therapy

Norepinephrine: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Norepinephrine. Risk C: Monitor therapy

Normethadone: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Normethadone. Risk X: Avoid combination

OLANZapine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of OLANZapine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Ondansetron: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Opicapone: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Opioid Agonists: Anticholinergic Agents may enhance the adverse/toxic effect of Opioid Agonists. Specifically, the risk for constipation and urinary retention may be increased with this combination. Risk C: Monitor therapy

Opioid Agonists: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Opium: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Opium. Risk X: Avoid combination

Oxatomide: May enhance the anticholinergic effect of Anticholinergic Agents. Risk X: Avoid combination

Oxitriptan: Serotonergic Agents (High Risk) may enhance the serotonergic effect of Oxitriptan. This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

OxyCODONE: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Management: Use of oxycodone is not recommended for patients taking MAOIs or within 14 days of MAOI discontinuation. If combined, use test doses and frequent titration of small doses while monitoring blood pressure, CNS depression, and signs of serotonin syndrome. Risk D: Consider therapy modification

OxyMORphone: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Ozanimod: May enhance the hypertensive effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Paliperidone: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Paliperidone. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Periciazine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Periciazine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Perphenazine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Perphenazine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Pheniramine: May enhance the anticholinergic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Pholcodine: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Risk X: Avoid combination

Pimozide: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Pimozide. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Pipamperone [INT]: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Pipamperone [INT]. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Pizotifen: Monoamine Oxidase Inhibitors may enhance the anticholinergic effect of Pizotifen. Risk X: Avoid combination

Polyethylene Glycol-Electrolyte Solution: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Polyethylene Glycol-Electrolyte Solution. Specifically, the risk of seizure may be increased. Risk C: Monitor therapy

Potassium Chloride: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Chloride. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium chloride. Risk X: Avoid combination

Potassium Citrate: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Citrate. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium citrate. Risk X: Avoid combination

Pramlintide: May enhance the anticholinergic effect of Anticholinergic Agents. These effects are specific to the GI tract. Risk X: Avoid combination

Prochlorperazine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Prochlorperazine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Promazine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Promazine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

QUEtiapine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of QUEtiapine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Ramosetron: Anticholinergic Agents may enhance the constipating effect of Ramosetron. Risk C: Monitor therapy

Ramosetron: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Reboxetine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Reboxetine. Risk X: Avoid combination

Remifentanil: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Remifentanil. Specifically, the risk for opioid toxicity (eg, respiratory depression) may be increased. Remifentanil may enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Management: The use of remifentanil is not recommended for patients taking monoamine oxidase inhibitors (MAOIs) or within 14 days of MAOI discontinuation. If coadministration is required, use test doses and titrate small doses of remifentanil frequently. Risk D: Consider therapy modification

Reserpine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Reserpine. Existing MAOI therapy can result in paradoxical effects of added reserpine (e.g., excitation, hypertension). Management: Monoamine oxidase inhibitors (MAOIs) should be avoided or used with great caution in patients who are also receiving reserpine. Monitor closely for paradoxical effects of reserpine (eg, excitation, hypertension). Risk D: Consider therapy modification

Revefenacin: Anticholinergic Agents may enhance the anticholinergic effect of Revefenacin. Risk X: Avoid combination

RisperiDONE: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of RisperiDONE. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Rivastigmine: Anticholinergic Agents may diminish the therapeutic effect of Rivastigmine. Rivastigmine may diminish the therapeutic effect of Anticholinergic Agents. Management: Use of rivastigmine with an anticholinergic agent is not recommended unless clinically necessary. If the combination is necessary, monitor for reduced anticholinergic effects. Risk D: Consider therapy modification

Secretin: Anticholinergic Agents may diminish the therapeutic effect of Secretin. Management: Avoid concomitant use of anticholinergic agents and secretin. Discontinue anticholinergic agents at least 5 half-lives prior to administration of secretin. Risk D: Consider therapy modification

Selective Serotonin Reuptake Inhibitors: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Serotonergic Non-Opioid CNS Depressants: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Serotonergic Opioids (High Risk): Methylene Blue may enhance the serotonergic effect of Serotonergic Opioids (High Risk). This could result in serotonin syndrome. Management: Consider alternatives to this drug combination. If combined, monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes). Risk D: Consider therapy modification

Serotonin 5-HT1D Receptor Agonists (Triptans): May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Monoamine Oxidase Inhibitors may increase the serum concentration of Serotonin 5-HT1D Receptor Agonists (Triptans). Risk X: Avoid combination

Serotonin/Norepinephrine Reuptake Inhibitors: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Sertindole: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Sertindole. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Sevoflurane: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Sevoflurane. Specifically, the risk of hemodynamic instability may be increased. Risk C: Monitor therapy

Sodium Phosphates: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Sodium Phosphates. Specifically, the risk of seizure or loss of consciousness may be increased in patients with significant sodium phosphate-induced fluid or electrolyte abnormalities. Risk C: Monitor therapy

Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Risk D: Consider therapy modification

Solriamfetol: Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Solriamfetol. Risk X: Avoid combination

St John's Wort: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. St John's Wort may decrease the serum concentration of Serotonergic Agents (High Risk). Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

SUFentanil: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Specifically, the risk for serotonin syndrome or opioid toxicities (eg, respiratory depression, coma) may be increased. Management: Sufentanil should not be used with monoamine oxidase (MAO) inhibitors (or within 14 days of stopping an MAO inhibitor) due to the potential for serotonin syndrome and/or excessive CNS depression. Risk X: Avoid combination

SulfaSALAzine: Methenamine may enhance the adverse/toxic effect of SulfaSALAzine. Specifically, the combination may result in the formation of an insoluble precipitate in the urine. Risk X: Avoid combination

Sulfonamide Antibiotics: Methenamine may enhance the adverse/toxic effect of Sulfonamide Antibiotics. Specifically, the combination may result in the formation of an insoluble precipitate in the urine. Risk X: Avoid combination

Sulpiride: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Sulpiride. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Syrian Rue: May enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor therapy

Tapentadol: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Specifically, the additive effects of norepinephrine may lead to adverse cardiovascular effects. Tapentadol may enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Risk X: Avoid combination

Tetrabenazine: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Tetrahydrozoline (Nasal): Monoamine Oxidase Inhibitors may enhance the hypertensive effect of Tetrahydrozoline (Nasal). Risk X: Avoid combination

Thiazide and Thiazide-Like Diuretics: May diminish the therapeutic effect of Methenamine. Risk C: Monitor therapy

Thioridazine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Thioridazine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Thiothixene: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Thiothixene. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Tianeptine: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Tiotropium: Anticholinergic Agents may enhance the anticholinergic effect of Tiotropium. Risk X: Avoid combination

Tricyclic Antidepressants: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Trifluoperazine: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Trifluoperazine. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Tryptophan: May enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid combination

Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Avoid use of live attenuated typhoid vaccine (Ty21a) in patients being treated with systemic antibacterial agents. Postpone vaccination until 3 days after cessation of antibiotics and avoid starting antibiotics within 3 days of last vaccine dose. Risk D: Consider therapy modification

Tyrosine: May enhance the hypertensive effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Umeclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Risk X: Avoid combination

Uva Ursi: Urinary Acidifying Agents may diminish the therapeutic effect of Uva Ursi. Management: Consider avoiding use of uva ursi with agents that acidify the urine, as this may impair uva ursi efficacy. Risk D: Consider therapy modification

Valbenazine: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Viloxazine: May enhance the hypertensive effect of Monoamine Oxidase Inhibitors. Risk X: Avoid combination

Ziprasidone: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Ziprasidone. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy

Zuclopenthixol: Agents With Seizure Threshold Lowering Potential may enhance the adverse/toxic effect of Zuclopenthixol. Specifically, the risk of seizures may be increased. Risk C: Monitor therapy