What Foods To Eat & Avoid When Taking Methenamine

Methenamine Hippurate is an antibiotic that kills germs that cause urinary tract infections. 

It is typically used on a long-term basis to treat chronic infections and prevent infection recurrence. It does not treat an active infection.

Methenamine is a member of the anti-infective drug class. It is a prescription medication that is approved for adults and children over the age of six.

Allergic responses such as itching or hives, swelling of the lips, face, or tongue, skin rash, dark urine, bladder pain, lower back pain, and painful, frequent urination are all possible side effects of this medication.

You should report these side effects to your doctor or a health care provider as soon as possible. 

Loss of appetite, diarrhea, nausea, stomach upset, and mouth sores are some common adverse reactions that do not necessitate medical treatment.

To help control bacteria in the urine, you may need to follow specific dietary advice while taking this medicine.  

So, familiarize yourself with the list of foods to eat or avoid when taking Methenamine.

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2 Foods To Avoid When Taking Methenamine

Methenamine is most effective in the presence of acidic urine. The drug is broken down into ammonia and formaldehyde in an acidic environment. 

Its mode of action is based on the production of formaldehyde, which has a nonspecific antibacterial effect by dissolving proteins and nucleic acids of bacteria.

Certain foods, such as milk and most fruits and juices, may interfere with the drug’s ability to prevent urinary infections

Let’s explore the foods and beverages that you should avoid while taking Methenamine.

1) Milk And Dairy Products

Methenamine should not be taken with any food or beverage that may affect urine pH, such as milk or milk products. 

These may cause urine to become alkaline, reducing methenamine’s efficacy by blocking its conversion to formaldehyde.

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2) Citrus juice

Orange juice is ineffective as a urinary acidifier and should not be used to achieve urine acidification. 

Furthermore, if consumed in significant quantities, citric acid may actually elevate urine pH.

Citrus fruits and juice do not make the urine acidic, even if they are high in citric acid. We may think the acid in the fruits and juice will make urine acidic too. But it’s quite the opposite.

Citrate is abundant in citrus juices. When taken orally, citrate is absorbed and essentially broken down to bicarbonate in the colon. 

This results in an alkali load, which raises urine pH and citrate excretion, making the urine alkaline.

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4 Foods To Eat While On Methenamine

Before you start taking this medicine, check your urine with phenaphthazine paper or another test to see if it is acid. If you have any questions about this, check with your healthcare professional.

Certain foods are beneficial while taking Methenamine, such as:

1) Cranberries

Cranberry juice can help keep urine acidic. The juice has a low pH of 2.5 as well as a unique blend of organic acids such as malic, quinic, shikimic, and citric acid.

Therefore, drinking cranberry juice, especially cranberry juice with vitamin C added, should be at the top of your list of foods to eat and drink while taking Methenamine.

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2) High Protein Diet

It is recommended that you consume more proteins to increase the acidity of your urine. Excess uric acid in the body causes urine acidity. 

Uric acid is produced in the body as a result of protein breakdown, so any diet with a high protein content will contribute to an increase in uric acid levels.

Protein also increases the quantity of acid produced in the body. The kidneys must filter these acids into the urine, lowering its pH.

3) Vitamin C

Some people combine Methenamine with vitamin C. This is because vitamin C can help in the acidification of urine. 

Methenamine is most effective when your urine is acidic. It is unlikely to form formaldehyde until the urine pH is highly acidic.

There is conflicting evidence on its effectiveness. However, 1 to 4 grams of vitamin C may be beneficial. It may improve the ability of Methenamine to reduce bacteria in the urine. 

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4) Plums And Prunes

Plums are antioxidant powerhouses that can provide critical nutrients like potassium and fiber while protecting your cells from injury. 

But more importantly, plums decrease urinary pH making it more acidic. And we know how acidic urine and Methenamine work their magic together.

What’s more, the potassium content in plums is also beneficial to blood pressure regulation. 

It aids your body’s elimination of sodium through urination and reduces tension in the walls of your blood vessels.

Dried plums, often known as prunes, are proven to help with a variety of health issues. One of the primary benefits of drinking prune juice to treat urinary infections is that it is naturally acidic.

This acidity is beneficial in two ways. For starters, it boosts the efficiency of Methenamine hippurate. Following that, bacteria that cause urinary tract infections do not grow in an acidic environment.

While the type of bacteria causing the infection must be considered, prune juice as a therapy may have some benefits in removing bacteria or stopping them from multiplying.

Foods to avoidFoods to eat
Dairy and milk productsCranberries and cranberry juice
Citrus drinksProtein-rich foods
Vitamin C
Plums and prunes

Other Interactions With Methenamine

Drug interactions can alter how your medications work or put you at risk for harmful adverse effects. 

Do not start, stop, or modify the dosage of any medications without first consulting your doctor.

Other medications, including prescription and over-the-counter medications, herbal supplements, and vitamins, may interact with Methenamine. 

Some medications that may interact with this drug include:

  • Products that reduce the quantity of acid in the urine (urinary alkalinizers such as antacids, potassium or sodium citrate, sodium bicarbonate, carbonic anhydrase inhibitors such as acetazolamide).
  • Sulfonamide drugs (including sulfamethizole, which are sulfa antibiotics)

Inform all of your healthcare providers about the medications you are currently taking and any new drugs or discontinued ones. 

This medicine may also interact with some laboratory tests, perhaps resulting in incorrect results. 

Make sure that laboratory personnel and all of your doctors are aware that you are taking this medication.

Various common foods and drinks, such as spicy meals, artificial sweeteners, alcohol, coffee, or caffeinated drinks, can irritate your bladder and increase UTI symptoms, so avoid them if you have symptoms of a urinary infection.

Sodas, in general, have been shown to irritate the bladder in individuals with chronic bladder inflammation, and they can worsen symptoms in people with a bladder infection. 

When it comes to exacerbating urinary tract infection symptoms, citrus-flavored drinks (imagine your favorite lemon-lime combo) and caffeinated sodas are the culprits. 

So, if you’re fighting a bladder infection, stick to water or cranberry juice as your beverage of choice.

Methenamine hippurate tablets should not be taken if you are allergic to it, to formaldehyde, or any inactive ingredient. 

All components are listed in the complete package insert; read them carefully.

Should You Take Methenamine With Food?

Doctors often recommend taking Methenamine after meals and before going to bed. This is because Methenamine might cause gastrointestinal issues.

People commonly take 500 mg twice daily or 1,000 mg four times daily, depending on the formulation. There is no set time limit for treatment, which can vary from person to person.

Take each dose with a full glass (or 8 ounces) of water or other liquid (excluding citrus juices and milk). 

Unless otherwise ordered by your doctor, drink plenty of water or other liquids every day. 

Drinking enough liquids will improve the performance of your kidneys and alleviate your discomfort.


Methenamine may be part of a comprehensive treatment plan that includes a special diet. 

Follow the diet plan recommended by your doctor or nutritionist. Get familiar with the foods you should consume or avoid when taking Methenamine to help control your condition.

You should avoid milk and citrus fruits like oranges, grapefruits, and lemons (including juices). 

Before using an antacid, speak with your doctor or healthcare professional, and only use the recommended type. Some antacids can make it harder for your body to absorb Methenamine.

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  1. Chwa A, Kavanagh K, Linnebur SA, Fixen DR. Evaluation of methenamine for urinary tract infection prevention in older adults: a review of the evidence. Ther Adv Drug Saf. 2019.
  2. Siener R. Can the manipulation of urinary pH by beverages assist with the prevention of stone recurrence? Urolithiasis. 2016.
  3. Jensen HD, Struve C, Christensen SB, Krogfelt KA. Cranberry Juice and Combinations of Its Organic Acids Are Effective against Experimental Urinary Tract Infection. Front Microbiol. 2017.

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