Methenamine Side Effects
For the Consumer
Applies to methenamine: oral suspension, oral tablet, oral tablet enteric coated
In addition to its needed effects, some unwanted effects may be caused by methenamine. In the event that any of these side effects do occur, they may require medical attention.
You should check with your doctor immediately if any of these side effects occur when taking methenamine:Less common
- Skin rash
- Blood in urine
- lower back pain
- pain or burning while urinating
Some of the side effects that can occur with methenamine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:Less common
- Nausea and vomiting
For Healthcare Professionals
Applies to methenamine: compounding powder, oral suspension, oral tablet
This drug was generally well tolerated. Minor side effects have been reported in less than 3.5% of patients and were reversible when the drug was stopped.[Ref]
Uncommon (0.1% to 1%): Rash, pruritus
Frequency not reported: Generalized skin rash[Ref]
Uncommon (0.1% to 1%): Gastric irritation
Frequency not reported: Nausea, vomiting, upset stomach, stomatitis, gastrointestinal disturbances, diarrhea, abdominal cramping[Ref]
High doses have been associated with albuminuria, gross hematuria, bladder irritation, and painful/frequent micturition.[Ref]
Uncommon (0.1% to 1%): Bladder irritation
Frequency not reported: Dysuria, hematuria, urinary frequency, albuminuria[Ref]
Frequency not reported: Elevated AST, elevated ALT[Ref]
Frequency not reported: Hypersensitivity reactions[Ref]
Frequency not reported: Anorexia
Frequency not reported: Anterior uveitis[Ref]
1. "Product Information. Hiprex (methenamine)." Hoechst Marion-Roussel Inc, Kansas City, MO.
2. Cerner Multum, Inc. "Australian Product Information." O 0
3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
4. Gleckman R, Alvarez S, Joubert D, Matthews S "Drug therapy reviews: methenamine mandelate and methenamine hippurate." Am J Hosp Pharm 36 (1979): 1509-12
5. "Product Information. Mandelamine (methenamine)." Parke-Davis, Morris Plains, NJ.
6. Australian Drug Evaluation Committee "Adverse effects of drugs commonly used in the treatment of urinary tract infection." Med J Aust 1 (1972): 435-8
7. Brumfitt W, Hamilton-Miller J, Gargan R, Cooper J, Smith GW "Long-term prophylaxis of urinary infections in women: comparative trial of trimethoprim, methenamine hippurate and topical povidone-iodine." J Urol 130 (1983): 1110-4
8. Brumfitt W, Cooper J, Hamilton-Miller J "Prevention of recurrent urinary infections in women: a comparative trial between nitrofurantoin and methenamine hippurate." J Urol 126 (1981): 71-4
9. Kolker RJ "Medication-induced bilateral anterior uveitis." Arch Ophthalmol 109 (1991): 1343
Not all side effects for methenamine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
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