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 Uribel Tabs cause fetal harm when
administered to a pregnant woman or can affect reproduction capacity. Uribel Tabs should be given to a pregnant woman only if clearly needed.
Breastfeeding
Problems in humans have not been documented; however, methenamine and traces of hyoscyamine are excreted in breast milk. Accordingly, Uribel Tabs 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 evaluate carcinogenic potential.
Pediatric use
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.
ADVERSE REACTIONS
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 Mission Pharmacal at 1-800-298-1087 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.