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Methenamine, Sodium Phosphate Monobasic, Phenyl Salicylate, Methylene Blue, and Hyoscyamine

Pronunciation

(meth EN a meen, SOW dee um FOS fate mon oh BAY sik, fen nil sa LIS i late, METH i leen bloo, & hye oh SYE a meen)

Index Terms

  • Hyoscyamine, Methenamine, Methylene Blue, Phenyl Salicylate, and Sodium Phosphate Monobasic
  • Hyoscyamine, Methenamine, Sodium Phosphate Monobasic, Phenyl Salicylate, and Methylene Blue
  • Meth/Meblue/Sod Phos/Psal/Hyos
  • Methen/M-Blue/Sal/Na Phos/Hyos
  • Methylene Blue, Methenamine, Sodium Phosphate Monobasic, Phenyl Salicylate, and Hyoscyamine
  • Mth/Me Blue/Sod Phos/Phen/Hyos
  • Phenyl Salicylate, Methenamine, Methylene Blue, Sodium Biphosphate, and Hyoscyamine
  • Sodium Phosphate Monobasic, Methenamine, Methylene Blue, Phenyl Salicylate, and Hyoscyamine

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule, oral:

Azuphen MB: Methenamine 120 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36 mg, methylene blue 10 mg, hyoscyamine sulfate 0.12 mg

Uramit MB: Methenamine 118 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36 mg, methylene blue 10 mg, hyoscyamine sulfate 0.12 mg

Uribel: Methenamine 118 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36 mg, methylene blue 10 mg, hyoscyamine sulfate 0.12 mg

UroAv-B: Methenamine 118 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36 mg, methylene blue 10 mg, hyoscyamine sulfate 0.12 mg

Uro-MP: Methenamine 118 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36 mg, methylene blue 10 mg, hyoscyamine sulfate 0.12 mg

Ustell: Methenamine 120 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36 mg, methylene blue 10 mg, hyoscyamine sulfate 0.12 mg

Uticap: Methenamine 120 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36 mg, methylene blue 10 mg, hyoscyamine sulfate 0.12 mg

Tablet, oral:

Hyolev MB: Methenamine 81 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 32.4 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Phosphasal: Methenamine 81.6 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36.2 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Ur N-C: Methenamine 81.6 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36.2 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Urelle: Methenamine 81 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 32.4 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Uretron D/S: Methenamine 81.6 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36.2 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Urimar-T: Methenamine 120 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36.2 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Urin DS: Methenamine 81.6 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36.2 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Uro-458: Methenamine 81 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 32.4 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

UroAv-81: Methenamine 81 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 32.4 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Uro-L: Methenamine 81 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 32.4 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg [DSC]

Utira-C: Methenamine 81.6 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36.2 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Utrona-C: Methenamine 81.6 mg, sodium phosphate monobasic 40.8 mg, phenyl salicylate 36.2 mg, methylene blue 10.8 mg, hyoscyamine sulfate 0.12 mg

Brand Names: U.S.

  • Azuphen MB
  • Hyolev MB
  • Phosphasal
  • Ur N-C
  • Uramit MB
  • Urelle
  • Uretron D/S
  • Uribel
  • Urimar-T
  • Urin DS
  • Uro-458
  • Uro-L [DSC]
  • Uro-MP
  • UroAv-81
  • UroAv-B
  • Ustell
  • Uticap
  • Utira-C
  • Utrona-C

Pharmacologic Category

  • Antibiotic, Miscellaneous

Use: Labeled Indications

Treatment of symptoms of irritative voiding; relief of local symptoms associated with urinary tract infections; relief of urinary tract symptoms caused by diagnostic procedures

Contraindications

Hypersensitivity to methenamine, hyoscyamine, methylene blue, or any component of the formulation

Dosing: Adult

Urinary tract symptoms: Oral: One tablet 4 times daily (follow by liberal fluid intake)

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Urinary tract symptoms: Children >6 years: Oral: Dosage must be individualized

Dosing: Renal Impairment

No dosage adjustment provided in manufacturer’s labeling.

Dosing: Hepatic Impairment

No dosage adjustment provided in manufacturer’s labeling.

Storage

Store at controlled room temperature of 15°C to 30°C (59°F to 86°F).

Drug Interactions

AbobotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of AbobotulinumtoxinA. Monitor therapy

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

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

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

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. 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. Avoid combination

Altretamine: May enhance the orthostatic hypotensive effect of Monoamine Oxidase Inhibitors. Monitor therapy

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

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

Amifampridine: May diminish the anticholinergic effect of Anticholinergic Agents. Anticholinergic Agents may diminish the therapeutic effect of Amifampridine. 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. Avoid combination

Antacids: May diminish the therapeutic effect of Methenamine. Consider therapy modification

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

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

Antiemetics (5HT3 Antagonists): May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

Antipsychotic Agents: Serotonin Modulators may enhance the adverse/toxic effect of Antipsychotic Agents. Specifically, serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotic Agents may enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

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

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

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

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

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

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

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

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

Blood Glucose Lowering Agents: Monoamine Oxidase Inhibitors may enhance the hypoglycemic effect of Blood Glucose Lowering Agents. 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). 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). Monitor therapy

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

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

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

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

CarBAMazepine: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Management: Avoid concurrent use of carbamazepine during, or within 14 days of discontinuing, treatment with a monoamine oxidase inhibitor. Avoid combination

Carbonic Anhydrase Inhibitors: May diminish the therapeutic effect of Methenamine. Management: Consider avoiding this combination. Monitor for decreased therapeutic effects of methenamine if used concomitant with a carbonic anhydrase inhibitor. Exceptions: Brinzolamide; Dorzolamide. Consider therapy modification

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

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

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

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

Cholera Vaccine: Antibiotics may diminish the therapeutic effect of Cholera Vaccine. Avoid combination

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

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

Codeine: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Codeine. Monitor therapy

COMT Inhibitors: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Consider therapy modification

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

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

Dapoxetine: May enhance the adverse/toxic effect of Serotonin Modulators. Avoid combination

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

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

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

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

Dihydrocodeine: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Monitor therapy

Diphenoxylate: May enhance the hypertensive effect of Monoamine Oxidase Inhibitors. 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. 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. Consider therapy modification

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

Doxylamine: Monoamine Oxidase Inhibitors may enhance the anticholinergic effect of Doxylamine. Management: The US manufacturer of Diclegis (doxylamine/pyridoxine) and the manufacturers of Canadian doxylamine products specifically lists use with monoamine oxidase inhibitors as contraindicated. Monitor therapy

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

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

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

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

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

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

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

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

Glucagon: Anticholinergic Agents may enhance the adverse/toxic effect of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Avoid combination

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

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

Heroin: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Heroin. Avoid combination

HYDROcodone: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of HYDROcodone. Management: Consider alternatives to this combination when possible. Consider therapy modification

HYDROmorphone: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of HYDROmorphone. Avoid combination

Indoramin: Monoamine Oxidase Inhibitors may enhance the hypotensive effect of Indoramin. 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 anticonvulsants. 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 anticonvulsants. 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 anticonvulsants. Consider therapy modification

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

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

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

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

Levodopa: 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. Management: The concomitant use of nonselective monoamine oxidase inhibitors (MAOIs) and levodopa is contraindicated. Discontinue the nonselective MAOI at least two weeks prior to initiating levodopa. Monitor patients taking a selective MAOIs and levodopa. Consider therapy modification

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

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

Linezolid: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Linezolid. Avoid combination

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

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

Meperidine: Monoamine Oxidase Inhibitors may enhance the serotonergic effect of Meperidine. This may cause serotonin syndrome. Avoid combination

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

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

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

Metaxalone: May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

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

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

Metoclopramide: Serotonin Modulators may enhance the adverse/toxic effect of Metoclopramide. This may be manifest as symptoms consistent with serotonin syndrome or neuroleptic malignant syndrome. Monitor therapy

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

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

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

Moclobemide: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Moclobemide. Avoid combination

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

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

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

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

Nefopam: Monoamine Oxidase Inhibitors may enhance the adverse/toxic effect of Nefopam. 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. Monitor therapy

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

OnabotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of OnabotulinumtoxinA. Monitor therapy

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

Opioid Analgesics: May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

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

OxyCODONE: May enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Management: Seek alternatives when possible. Avoid use of oxycodone/naltrexone during and within 14 days after monoamine oxidase inhibitor treatment. Non-US labeling for some oxycodone products states that such use is contraindicated. Consider therapy modification

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

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

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

Pindolol: Monoamine Oxidase Inhibitors may enhance the hypotensive effect of Pindolol. Management: Canadian labeling for pindolol states that concurrent use with a monoamine oxidase inhibitor is not recommended. Consider therapy modification

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

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. Avoid combination

Potassium Citrate: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Citrate. Avoid combination

Pramlintide: May enhance the anticholinergic effect of Anticholinergic Agents. These effects are specific to the GI tract. Consider therapy modification

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

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

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. Consider therapy modification

RimabotulinumtoxinB: Anticholinergic Agents may enhance the anticholinergic effect of RimabotulinumtoxinB. Monitor therapy

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. Consider therapy modification

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

Serotonin Modulators: Methylene Blue may enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Exceptions: Nicergoline. Avoid combination

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

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. Consider therapy modification

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. 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. Avoid combination

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. Avoid combination

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

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

Thiazide and Thiazide-Like Diuretics: Anticholinergic Agents may increase the serum concentration of Thiazide and Thiazide-Like Diuretics. Monitor therapy

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

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

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

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

Tryptophan: May enhance the adverse/toxic effect of Monoamine Oxidase Inhibitors. Avoid combination

Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Vaccination with live attenuated typhoid vaccine (Ty21a) should be avoided in patients being treated with systemic antibacterial agents. Use of this vaccine should be postponed until at least 3 days after cessation of antibacterial agents. Consider therapy modification

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

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

Adverse Reactions

Frequency not defined.

Cardiovascular: Flushing, tachycardia

Central nervous system: Dizziness

Gastrointestinal: Nausea, vomiting, xerostomia

Genitourinary: Acute urinary retention, difficulty in micturition, urine discoloration (blue)

Ophthalmic: Blurred vision

Respiratory: Dyspnea

Warnings/Precautions

Concerns related to adverse effects:

• Belladonna alkaloid allergy: Use with caution in patients with a history of intolerance to belladonna alkaloids.

• Blurred vision: Discontinue use immediately if blurred vision occurs.

• Dizziness: Discontinue use immediately if dizziness occurs.

• Salicylate allergy: Use with caution in patients with a history of intolerance to salicylates.

• Tachycardia: Discontinue use immediately if tachycardia occurs.

Disease-related concerns:

• Cardiovascular disease: Use with caution in patients with cardiovascular disease (cardiac arrhythmias, HF, coronary heart disease, mitral stenosis).

• Gastrointestinal tract obstruction: Use with caution in patients with gastrointestinal tract obstruction.

• Glaucoma: Use with caution in patients with glaucoma.

• Myasthenia gravis: Use with caution in patients with myasthenia gravis.

• Obstructive uropathy: Use with caution in patients with obstructive uropathy (bladder neck obstruction or prostatic hyperplasia).

Special populations:

• Pediatric: Safety and efficacy have not been established in children ≤6 years of age.

Other warnings/precautions:

• Urine discoloration: May cause urinary discoloration (blue).

Pregnancy Risk Factor

C

Pregnancy Considerations

Reproduction studies have not been conducted with this combination. Methenamine and hyoscyamine cross the placenta.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience nausea, vomiting, fatigue, dry mouth, urine or stool discoloration, or flushing. Have patient report immediately to prescriber tachycardia, blurred vision, dizziness, shortness of breath, or difficult urination (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

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