Generic Name: methenamine/sodium phosphate (meth-EN-a-meen/SOE-dee-um FOS-fate)
Brand Name: Examples include Uroqid-Acid No. 2 and Visqid A/A
Methenamine/sodium biphosphate is used for:
Preventing and treating urinary tract infections.
Methenamine/sodium biphosphate is a urinary antiseptic and urinary acidifier combination. It works by concentrating in the urine as formaldehyde, which kills bacteria in the urine.
Do NOT use methenamine/sodium biphosphate if:
- you are allergic to any ingredient in methenamine/sodium biphosphate
- you have kidney problems, high blood phosphate levels, or you are severely dehydrated
- you are taking sulfamethizole
Contact your doctor or health care provider right away if any of these apply to you.
Before using methenamine/sodium biphosphate:
Some medical conditions may interact with methenamine/sodium biphosphate. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:
- if you are pregnant, planning to become pregnant, or are breast-feeding
- if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
- if you have allergies to medicines, foods, or other substances
- if you are on a low-salt (sodium) diet or are dehydrated
- if you have diarrhea, a certain infection (parenchymal infection) causing fever or chills, toxemia of pregnancy, liver problems, heart problems (eg, heart failure), swelling, breathing problems, high blood sodium levels, high blood pressure, certain hormone imbalances (hypoparathyroidism), inflammation of the pancreas (pancreatitis), or gout
Some MEDICINES MAY INTERACT with methenamine/sodium biphosphate. Tell your health care provider if you are taking any other medicines, especially any of the following:
- Antacids, carbonic anhydrase inhibitors (eg, acetazolamide), sulfonamides (eg, sulfamethizole), thiazide diuretics (eg, hydrochlorothiazide), or urinary alkalinizers (eg, sodium bicarbonate) because they may decrease methenamine/sodium biphosphate's effectiveness
- Corticosteroids, diazoxide, guanethidine, hydralazine, methyldopa, or rauwolfia alkaloids (eg, reserpine) because the risk of high blood sodium levels may be increased
- Salicylates (eg, aspirin) because the risk of their side effects may be increased by methenamine/sodium biphosphate
This may not be a complete list of all interactions that may occur. Ask your health care provider if methenamine/sodium biphosphate may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.
How to use methenamine/sodium biphosphate:
Use methenamine/sodium biphosphate as directed by your doctor. Check the label on the medicine for exact dosing instructions.
- Take methenamine/sodium biphosphate by mouth with or without food. If stomach upset occurs, take with food to reduce stomach irritation.
- Before you begin using an antacid, check with your doctor or pharmacist.
- Drinking extra fluids while you are taking methenamine/sodium biphosphate is recommended. Check with your doctor for instructions.
- Continue to take methenamine/sodium biphosphate even if you feel well. Do not miss any doses.
- If you miss a dose of methenamine/sodium biphosphate, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.
Ask your health care provider any questions you may have about how to use methenamine/sodium biphosphate.
Important safety information:
- It is important that your urine be acidic while you are taking methenamine/sodium biphosphate. Most fruits, milk products, and antacids containing sodium carbonate or bicarbonate should be restricted or avoided while you take methenamine/sodium biphosphate because they may increase the pH level of your urine. Check with your doctor to see if you should eat or avoid certain foods to keep your urine acidic.
- Methenamine/sodium biphosphate may interfere with certain lab test results, including urinary estriol or catecholamine levels. Be sure your doctor and lab personnel know you are taking methenamine/sodium biphosphate.
- Lab tests, including urine pH, may be performed while you use methenamine/sodium biphosphate. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
- PREGNANCY and BREAST-FEEDING: It is not known if methenamine/sodium biphosphate can cause harm to the fetus. If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of taking methenamine/sodium biphosphate while you are pregnant. Methenamine/sodium biphosphate is found in breast milk. If you are or will be breast-feeding while you take methenamine/sodium biphosphate, check with your doctor. Discuss any possible risks to your baby.
Possible side effects of methenamine/sodium biphosphate:
All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:
Seek medical attention right away if any of these SEVERE side effects occur:
Nausea; upset stomach.
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blood in the urine; bone or joint pain; increased, decreased, or painful urination; mental or mood changes; muscle cramps; numbness or tingling of the lips, hands, or feet; seizures; stomach pain; unusual thirst; unusual weakness; unusual weight gain; vomiting.
This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.
If OVERDOSE is suspected:
Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately.Proper storage of methenamine/sodium biphosphate:
Store methenamine/sodium biphosphate at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep methenamine/sodium biphosphate out of the reach of children and away from pets.
- If you have any questions about methenamine/sodium biphosphate, please talk with your doctor, pharmacist, or other health care provider.
- Methenamine/sodium biphosphate is to be used only by the patient for whom it is prescribed. Do not share it with other people.
- If your symptoms do not improve or if they become worse, check with your doctor.
- Check with your pharmacist about how to dispose of unused medicine.
This information should not be used to decide whether or not to take methenamine/sodium biphosphate or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about methenamine/sodium biphosphate. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to methenamine/sodium biphosphate. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using methenamine/sodium biphosphate.
Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.