Hyoscyamine produces many effects in the body, including relief from muscle spasms.

Methenamine and methylene blue work as mild antiseptics that fight bacteria in the urine and bladder.

Phenyl salicylate is a mild pain reliever.

Sodium biphosphate is a form of phosphorus, which is a naturally occurring substance that is important in every cell in the body.

Vilamit MB is a combination medicine used to treat bladder irritation (pain, spasms, inflammation) caused by urinary tract infection. Vilamit MB is also used to prevent bladder discomfort during a medical procedure.

Vilamit MB may also be used for purposes not listed in this medication guide.

Many drugs can interact with methylene blue. During your treatment with this medicine, do not start or stop using any other medications without your doctor's advice.

If you take an antidepressant or psychiatric medication, call your doctor right away if you have signs of a serious drug interaction, including: confusion, memory problems, feeling hyperactive (mentally or physically), loss of coordination, muscle twitching, shivering, sweating, diarrhea, and/or fever.

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Drink plenty of liquids while you are taking this medicine.

Hyoscyamine can slow your digestion, and it may take longer for your body to absorb any medicines you take by mouth.

Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

You should not use this medicine if you are allergic to hyoscyamine, methenamine, methylene blue, phenyl salicylate, or sodium biphosphate.

During your treatment with this medicine, do not start or stop using any other medications unless your doctor tells you to.

To make sure this medicine is safe for you, tell your doctor if you have:

• heart disease;

• a heart rhythm disorder;

• congestive heart failure;

• coronary heart disease;

• a heart valve disorder;

• glaucoma;

• an enlarged prostate or bladder obstruction;

• myasthenia gravis;

• an ulcer or obstruction in your stomach;

• an allergy to belladonna (Donnatal and others); or

• an allergy to salicylates (such as aspirin, choline magnesium trisalicylate, magnesium salicylate).

It is not known whether this medication will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medicine.

This medicine can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Do not give this medicine to a child without medical advice.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Avoid taking an antacid or anti-diarrhea medicine within 1 hour before or after you take hyoscyamine, methenamine, methylene blue, phenyl salicylate, and sodium biphosphate. Antacids or anti-diarrhea medicine can make it harder for your body to absorb hyoscyamine.

If you also take ketoconazole (Nizoral), wait at least 2 hours after taking it before you take hyoscyamine, methenamine, methylene blue, phenyl salicylate, and sodium biphosphate.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

This medicine may cause serious side effects. Stop using this medicine and call your doctor at once if you have:

• severe dizziness, blurred vision, fast heart rate;

• painful or difficult urination; or

• shortness of breath.

Older adults may be more likely to have side effects from this medication.

Methylene blue will most likely cause your urine or stools to appear blue or green in color. This is a normal side effect of the medication and will not cause any harm.

Common side effects of Vilamit MB may include:

• dizziness, drowsiness;

• dry mouth; or

• nausea, vomiting.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Many drugs can interact with methylene blue. Tell your doctor about all other medications you use. You may need to stop using certain medicines (in some cases for up to 5 weeks before you start treatment with Vilamit MB). However, do not stop taking any of your medications without your doctor's advice. This includes:

• any type of antidepressant;

• diet pills, stimulants, cold or allergy medicines, ADHD medication;

• narcotic pain medicine;

• medication to treat Parkinson's disease or restless leg syndrome; or

• a "triptan" migraine headache medication.

Taking any of the above medications while you are treated with medicine that contains methylene blue can cause high levels of serotonin in the body. Call your doctor right away if you have symptoms of this condition: agitation, hallucinations, fever, fast heart rate, overactive reflexes, nausea, vomiting, diarrhea, loss of coordination, or fainting.

Many drugs can interact with this medicine. Not all possible interactions are listed here. Also, hyoscyamine can make it harder for your body to absorb other medications you take by mouth. Tell your doctor about all your medications and any you start or stop using, especially:

• a diuretic or "water pill";

• medicines that change the acidity of your urine--sodium bicarbonate, potassium citrate, sodium citrate with citric acid or potassium;

• bladder or urinary medicines--darifenacin, fesoterodine, oxybutynin, tolterodine, solifenacin; or

• a sulfa drug.

This list is not complete and many other drugs can interact with Vilamit MB. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.