What is Methenamine antibiotic used for?

Why did doctors prescribe Methenamine medicine?

Methenamine is used to eliminate bacteria or to control or prevent returning urinary tract infections caused by certain bacteria. This medication is a type of antibiotic that is used to stop the growth of bacteria in urine, you can’t use this medication on the active infection. For that you have to use the other medication to cure the infection first then you can use this antibiotic on an infection.

Before using this methenamine antibiotic, you should know that it will not work for colds, flu, or other viral infections. In the urinary tract, against bacterial infections, this antibiotic is very effective. Some other types of infections for which this methenamine antibiotic will not work such as bacterial infections (in the blood) or viral infections (the common cold or flu). 

Usually, to prevent recurrence of infections or in the treatment of chronic infections, the methenamine antibiotic is used on a long-term basis. If you want to make the urine acidic then this medication will help you because it contains an ingredient that will help you for this. If you want to kill the bacteria and your urine is acidic then methenamine turns into formaldehyde. If you are using this medication unnecessarily or doing misuse of any antibiotic can lead to its decreased effectiveness.

How should this medicine be used?

Methenamine is available in the form of a tablet and a liquid to take by mouth. Usually, your healthcare professionals will prescribe you to take two times a day after every 12 hours or four times a day after meals and at bedtime with a full glass of water or with food.

Ensure to follow the directions exactly on your prescription label carefully. Don’t ever try to take less or more of this medication than prescribed by your doctor or pharmacists.  The dosage of this medication depends on your medical condition or your response to treatment and if you are using the methenamine medication on your children then the dosage is based on age and weight.

Always take methenamine at around the same time each and every day. To see the most benefit of this medication use it regularly. And after that, if you feel your condition doesn’t improve then you may contact your healthcare professionals. Without talking to your doctor, do not stop using methenamine even if you feel well. Your doctor will tell you when you have stopped using this medication. If you don’t understand any of the parts then ask your healthcare provider to explain all the things again.

What special dietary plans should I follow?

Always follow your dietary recommendations and exercise plan made by your healthcare professional because methenamine medicine can cause an upset stomach. So, always take this medication with food or milk. If your doctor didn’t give you any instructions, you can continue your normal diet by just avoiding fast food. 

What special precautions could I take?

You should have followed this special precaution before using the methenamine:

  • If you are allergic to methenamine, aspirin, tartrazine, or any other drugs then tell your doctor and pharmacist and ask them for all ingredients of methenamine medication by which you are allergic.
  • If you have or have ever had kidney, liver disease, or dehydration then tell your doctor and pharmacist. 
  • If you are breastfeeding, pregnant, or plan to become pregnant. If you become pregnant while you are using methenamine medication then tell your doctor and pharmacist immediately. 
  • If you are having surgery while you are taking this medication then tell your doctor and dentist.
  • If you are taking some vitamins, nutritional supplements, prescription, and non-prescription medication or drugs and any other drug or medicine, and herbal products, or planning to take them while using this medication then tell your doctor and pharmacist. 
  • This can be very harmful to your infant. So, if you are breastfeeding then tell your doctor and pharmacist because it can pass into breast milk.

If you have experienced or faced any of the problems mentioned above then contact your health care professionals immediately. Follow all the mentioned precautions carefully, these are all precautions that you can take while using this product.

What are other uses of methenamine?

And if you want to know some other uses of this medication in detail then contact your healthcare professional and you can ask them for more information or other uses of methenamine.

What are methenamine side effects?

Methenamine is a medication that can be used only for serious side effects. That’s why this medication can only be used by people who have some serious side effects. Without your healthcare professionals don’t try to use this medication and they will suggest this medication by judging the most benefit to you is greater than the risk of side effects. Don’t try to use it for a longer time period than prescribed. 

Contact your healthcare professionals immediately, if you are having any of these side effects or symptoms mentioned below while you are using this medication. 

Some common methenamine side effects:

  • You’ll feel an upset stomach.
  • You’ll feel vomiting.
  • You’ll feel diarrhea.
  • You’ll feel stomach cramps.
  • You’ll feel a loss of appetite.

Some serious methenamine side effects:

  • You’ll feel skin rash.
  • You’ll feel hives.
  • You’ll feel itching (allergic reaction).
  • You’ll feel nausea.
  • You’ll feel bladder irritation, painful/frequent urination, and bloody/pink urine. 
  • You’ll feel mouth sores. 
  • You’ll feel an unusual headache.
  • You’ll feel ringing in your ears.
  • You’ll feel muscle cramps. 
  • You’ll feel swelling of the arms/legs.

This is not the complete list of all symptoms and side effects of this medication. In case, if you are facing any unusual problems and do not go away or are getting worse then immediately contact your health care professionals.

If you are in the United States and you are facing these serious side effects or someone near you then you can contact the Food and Drug Administration (FDA) or call at 1-888-463-6332 or at www.fda.gov/medwatch.

What do I do if I forget a dose?

If you forgot to take this medication and if it is near the time of your next dose then we suggest you please skip that dose and take it at the next dose at the regular time. Don’t take the dose at irregular times. It makes your dose double.

What are the Interactions of Methenamine medication?

Your healthcare professionals can already be aware of any drug interactions. Don’t try to change, stop, or start the dosage of any medicine before checking or talking to your doctor for his/her approval. 

Some products that can interact with methenamine: 

  • Sulfonamide drugs 
  • Sulfa antibiotics such as sulfamethizole
  • Urinary alkalinizers such as antacids
  • Sodium bicarbonate
  • Potassium 
  • Sodium citrate
  • Carbonic anhydrase inhibitors such as acetazolamide

This documentation doesn’t contain all the possible interactions. So, before using the methenamine, tell your healthcare professionals of all the products you use. If you are using vitamins, nutritional supplements, some prescription and nonprescription medications or drugs, other herbal products, or planning to take them, then tell your healthcare professionals before starting the treatment with this product. These products also can cause drowsiness to tell your healthcare professionals about the products.

What can I know about the storage and disposal of this medication?

Store this medication at room temperature and keep them away from light or excessive heat and moisture. And put them away from the reach of the pets and children, we suggest you put that medicine in a tightly closed container in which they came because there are as many containers like eye drops, creams, patches, and inhalers that are not child-resistant and young children or pets can easily open them.

You should have disposed of all the medication that is unneeded in a special way to ensure that children, pets, and other people can’t consume them. You can not flush them or pour them into the drain. You can return them to the pharmacist or the best way is that you can take back the program for returning your medicines.

What other information should I know?

If you are taking any prescription and non-prescription medication or drugs, while you are using this medication, it is very important to tell your healthcare professionals about this. To make it easy and unforgettable, you can create a list of all prescription and non-prescription medications or drugs and any other drug or medicine you are taking. You can show that list to your healthcare professionals or pharmacists at the time of visit or meeting them. It would help you in case of emergencies. It would help you in case of emergencies.

At the time of meeting your healthcare professionals, don’t forget to carry the laboratory report. And the most important thing is to never miss your doctor and laboratory appointments because your healthcare professionals will check the response of this medicine then he/she will tell you the update or other pieces of information. So, keep all your appointments with your doctor, pharmacist, and the laboratory. And before having any laboratory test, if you are already taking this product then tell your doctor and the laboratory personnel. Talk to your healthcare professionals if you feel your health condition is getting worse or your dose may need to be adjusted.


Hope you find this article very useful. Please tell us your experience with this article in the comment section and keep visiting for further pieces of information.

Leave a Comment

Your email address will not be published. Required fields are marked *