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

Uretron D/S tablets are indicated for the treatment of symptoms of irritative voiding. Indicated for the relief of local symptoms, such as inflammation, hypermotility, and pain, which accompany lower urinary tract infections. Indicated for the relief of urinary tract symptoms caused by diagnostic procedures.

Hypersensitivity to any of the ingredients is possible. Risk benefits should be carefully considered when the following medical problems exist: cardiac disease (especially cardiac arrhythmias, congestive heart failure, coronary heart disease, and mitral stenosis); gastrointestinal tract obstructive disease; glaucoma; myasthenia gravis, acute urinary retention may be precipitated in obstructive uropathy (such as bladder neck obstruction due to prostatic hypertrophy).

Do not exceed recommended dosage. If rapid pulse, dizziness or blurring of vision occurs discontinue use immediately.

Cross sensitivity and/or related problems Patients intolerant of belladonna alkaloids or salicylates may be intolerant of this medication also. Delay in gastric emptying could complicate the management of gastric ulcers. Pregnancy/Reproduction FDA Pregnancy Category C Hyoscyamine and methenamine cross the placenta. Studies concerning the effect of hyoscyamine and methenamine on pregnancy and reproduction have not been done in animals or humans. Thus it is not known whether Uretron D/S tablets cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Uretron D/S should be given to a pregnant woman only if clearly needed. Breast feeding Problems in humans have not been documented; however, methenamine and traces of hyoscyamine are excreted in breast milk. Accordingly, Uretron D/S tablets should be given to a nursing mother with caution and only if clearly needed. Prolonged use There have been no studies to establish the safety of prolonged use in humans. No known long-term animal studies have been performed to valuate carcinogenic potential. Pediatric Infants and young children are especially susceptible to the toxic effect of the belladonna alkaloids. Geriatric Use Use with caution in elderly patients as they may respond to usual doses of hyoscyamine with excitement, agitation, drowsiness or confusion.

Cardiovascular: rapid heartbeat, flushing Central Nervous System: blurred vision, dizziness, drowsiness Genitourinary: difficult micturition, acute urinary retention Gastrointestinal: dry mouth, nausea and vomiting Respiratory: shortness of breath or trouble breathing Serious allergic reactions to this drug are rare. Seek immediate medical attention if you notice symptoms of a serious allergic reaction, including itching, rash, severe dizziness, swelling or trouble breathing. This medication can cause urine and sometimes stools to turn blue to blue-green. This effect is harmless and will subside after medication is stopped. Call your doctor or physician for medical advice about side effects. To report SUSPECTED ADVERSE REACTIONS, contact A.G. Marin Pharmaceuticals at 305-593-5333 or FDA at 1-800-FDA-1088, www.fda.gov/medwatch. Drug interactions As a result of hyoscyamine's effects on gastrointestinal motility and gastric emptying, absorption of other oral medications may be decreased during concurrent use with this combination medication. Methylene blue inhibits a range of CYP isozymes in vitro, including 1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4/5. This interaction could be more pronounced with narrow therapeutic index drugs that are metabolized by one of these enzymes (e.g., digoxin, warfarin, phenytoin, alfentanil, cyclosporine, dihydroergotamine, ergotamine, fentanyl, pimozide, quinidine, sirolimus and tacrolimus). However, the clinical relevance of these in vitro interactions is unknown. Urinary alkalizers and thiazide diuretics: May cause the urine to become alkaline reducing the effectiveness of methenamine by inhibiting its conversion to formaldehyde. Antimuscarinics : Concurrent use may intensify antimuscarinic effects of hyoscyamine because of secondary antimuscarinic activities of these medications. Antacids/antidiarrheals: Concurrent use may reduce absorption of hyoscyamine resulting in decreased therapeutic effectiveness. Concurrent use with antacids may cause urine to become alkaline reducing the effectiveness of methenamine by inhibiting its conversion to formaldehyde. Doses of these medications should be spaced 1 hour apart from doses of hyoscyamine. Antimyasthenics: Concurrent use with hyoscyamine may further reduce intestinal motility, therefore, caution is recommended. Ketoconazole and hyoscyamine may cause increased gastrointestinal pH. Concurrent administration with hyoscyamine may result in marked reduction in the absorption of ketoconazole. Patients should be advised to take this combination at least 2 hours after ketoconazole. Monoamine oxidase (MAO) inhibitors: Concurrent use with hyoscyamine may intensify antimuscarinic side effects. Opioid (narcotic) analgesics may result in increased risk of severe constipation. Sulfonamides: These drugs may precipitate with formaldehyde in the urine increasing the danger of crystalluria. Patients should be advised that the urine and/or stools may become blue to blue-green as a result of the excretion of methylene blue.

As a result of hyoscyamine's effects on gastrointestinal motility and gastric emptying, absorption of other oral medications may be decreased during concurrent use with this combination medication. Methylene blue inhibits a range of CYP isozymes in vitro, including 1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4/5. This interaction could be more pronounced with narrow therapeutic index drugs that are metabolized by one of these enzymes (e.g., digoxin, warfarin, phenytoin, alfentanil, cyclosporine, dihydroergotamine, ergotamine, fentanyl, pimozide, quinidine, sirolimus and tacrolimus). However, the clinical relevance of these in vitro interactions is unknown. Urinary alkalizers and thiazide diuretics: May cause the urine to become alkaline reducing the effectiveness of methenamine by inhibiting its conversion to formaldehyde. Antimuscarinics : Concurrent use may intensify antimuscarinic effects of hyoscyamine because of secondary antimuscarinic activities of these medications. Antacids/antidiarrheals: Concurrent use may reduce absorption of hyoscyamine resulting in decreased therapeutic effectiveness. Concurrent use with antacids may cause urine to become alkaline reducing the effectiveness of methenamine by inhibiting its conversion to formaldehyde. Doses of these medications should be spaced 1 hour apart from doses of hyoscyamine. Antimyasthenics: Concurrent use with hyoscyamine may further reduce intestinal motility, therefore, caution is recommended. Ketoconazole and hyoscyamine may cause increased gastrointestinal pH. Concurrent administration with hyoscyamine may result in marked reduction in the absorption of ketoconazole. Patients should be advised to take this combination at least 2 hours after ketoconazole. Monoamine oxidase (MAO) inhibitors: Concurrent use with hyoscyamine may intensify antimuscarinic side effects. Opioid (narcotic) analgesics may result in increased risk of severe constipation. Sulfonamides: These drugs may precipitate with formaldehyde in the urine increasing the danger of crystalluria. Patients should be advised that the urine and/or stools may become blue to blue-green as a result of the excretion of methylene blue.

/Reproduction FDA Pregnancy Category C Hyoscyamine and methenamine cross the placenta. Studies concerning the effect of hyoscyamine and methenamine on pregnancy and reproduction have not been done in animals or humans. Thus it is not known whether Uretron D/S tablets cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Uretron D/S should be given to a pregnant woman only if clearly needed.

Breast feeding Problems in humans have not been documented; however, methenamine and traces of hyoscyamine are excreted in breast milk. Accordingly, Uretron D/S tablets should be given to a nursing mother with caution and only if clearly needed.

Pediatric Infants and young children are especially susceptible to the toxic effect of the belladonna alkaloids.

Use with caution in elderly patients as they may respond to usual doses of hyoscyamine with excitement, agitation, drowsiness or confusion.