methenamine/sodium salicylate/benzoic acid

Action and Spectrum

Actions and Spectrum: 

methenamine is a medication used to prevent urinary tract infections. It releases formaldehyde in the urine, creating an acidic environment that is inhospitable to bacteria. sodium salicylate is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain and reduce inflammation. benzoic acid is a preservative commonly used in food and cosmetic products. 

The combination of methenamine, sodium salicylate, and benzoic acid is sometimes used to treat mild urinary tract infections. This combination works by reducing inflammation in the urinary tract, creating an acidic environment that is inhospitable to bacteria, and preventing the growth of bacteria that can cause infections. 

The spectrum of this combination of medications is limited to treating mild urinary tract infections. It is ineffective against more severe infections or infections caused by resistant bacteria. Additionally, it may not be appropriate for people with certain medical conditions or taking certain medications, so it is essential to talk to a healthcare provider before using this medication. 

Drug Interaction

Adverse Reaction

Frequency defined 

1-10% 

Dysuria 

Rash 

Gastric upset 

Nausea 

Frequency not defined 

Angioedema 

Dermatologic problems 

Hearing loss 

GI pain/ulceration/bleeding 

Bronchospasm 

CNS alteration 

Hepatotoxicity 

Black Box Warning

Contraindication / Caution

Contraindication/Caution: 

Several contraindications and precautions are associated with using methenamine/sodium salicylate/benzoic acid. These include: 

• Allergy: Do not use this medication if you are allergic to any of its ingredients. 
• Salicylate sensitivity: If you are sensitive to salicylates, such as aspirin, you may also be sensitive to sodium salicylate and should avoid this medication. 
• Kidney disease: methenamine can accumulate in the kidneys and cause damage in people with kidney disease. Therefore, it should be used cautiously in people with impaired kidney function. 
• Liver disease: benzoic acid is metabolized in the liver and should be used cautiously in people with liver disease. 
• Pregnancy and breastfeeding: The safety of this medication during pregnancy and breastfeeding is not well established, and it should only be used if the benefits outweigh the risks. 
• Interactions with other medications: methenamine/sodium salicylate/benzoic acid may interact with other medications, including antacids, diuretics, and blood thinners. You must talk to your healthcare provider about all medications you are taking before using this medication. 
• Children: This medication is not recommended for children under 6. 

Pregnancy / Lactation

Pregnancy consideration:  

Category C 

Breastfeeding warnings:  

methenamine is excreted in the breastmilk, posing a risk to a breastfed infant. Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: No evidence of risk to the fetus is found in animal reproduction studies, and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for a human product; Pregnant women must take care of the potential risks. 
• Category D: There is adequate data with sufficient evidence of human fetal risk from various platforms. However, despite potential dangers may be used only in emergencies for potential benefits. 
• Category X: Drugs listed in this category outweigh the risks over benefits. The drug is not for pregnant women. 
• Category N: No data for the drug under this category is available. 

Pharmacology

Pharmacology: 

methenamine/sodium salicylate/benzoic acid is a combination medication to prevent and treat mild urinary tract infections. Each component of the medication has a different pharmacology: 

• methenamine: methenamine is a prodrug converted to formaldehyde in acidic urine. Formaldehyde is a bactericidal agent that works by disrupting bacterial metabolism and causing cell death. It is effective against a variety of gram-negative and gram-positive bacteria. 
• sodium salicylate: sodium salicylate is a nonsteroidal anti-inflammatory drug (NSAID) that works by inhibiting the production of prostaglandins. Prostaglandins are chemical messengers that are involved in inflammation and pain. By blocking their production, sodium salicylate reduces inflammation and pain. 
• benzoic acid: benzoic acid is a preservative commonly used in food and cosmetic products. This medication is used as an acidifier to lower urine pH. By creating an acidic environment, benzoic acid makes it more difficult for bacteria to grow and thrive in the urinary tract. 

Pharmacodynamics: 

The pharmacodynamics of methenamine/sodium salicylate/benzoic acid is related to the pharmacological properties of each component of the medication. 

methenamine is a prodrug that is converted to formaldehyde in acidic urine. Formaldehyde is a bactericidal agent that works by disrupting bacterial metabolism and causing cell death. Formaldehyde has a broad spectrum of activity against gram-negative and gram-positive bacteria, making it an effective antimicrobial agent. 

sodium salicylate is a nonsteroidal anti-inflammatory drug (NSAID) that works by inhibiting the production of prostaglandins. Prostaglandins are chemical messengers that are involved in inflammation and pain. By blocking their production, sodium salicylate reduces inflammation and pain. 

benzoic acid is a preservative commonly used in food and cosmetic products. This medication is used as an acidifier to lower urine pH. By creating an acidic environment, benzoic acid makes it more difficult for bacteria to grow and thrive in the urinary tract. 

Pharmacokinetics: 

Absorption 

For methenamine, the half-life is 3-6 hours 

The drug gets well absorbed; 10-30% of it is hydrolyzed via gastric acid (if the tablet is not enteric coated tablet) 

Distribution 

The peak urine time (for formaldehyde) is 2 hours for hippurate salt and 3-8 hours for mandelate salt 

Metabolism 

The liver metabolizes 10-25% of the drug  

Elimination and Excretion 

90% of the drug is excreted in urine  

Adminstartion

Administration 

methenamine/sodium salicylate/benzoic acid is a medication that prevents urinary tract infections. It combines three active ingredients: methenamine, sodium salicylate, and benzoic acid. 

methenamine is an antibiotic that works by preventing the growth of bacteria in the urinary tract. sodium salicylate and benzoic acid work together to create an acidic environment in the urine, which makes it difficult for bacteria to grow. 

The medication is usually taken orally as a tablet or capsule, and following the dosage instructions provided by your healthcare provider is essential. The usual adult dosage is one tablet or capsule taken four times daily. 

Plenty of fluid intake is essential while taking this medication to help flush the urinary tract and prevent the formation of kidney stones. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: methenamine/sodium salicylate / benzoic acid 

Pronounced: meh-THEH-na-meen/so-dee-um sal-ee-cilate/ ben-zo-ic acid  

Why do we use methenamine/sodium salicylate/benzoic acid? 

methenamine, sodium salicylate, and benzoic acid are commonly used in a medication called methenamine hippurate, which is used to prevent urinary tract infections (UTIs). 

methenamine is an antibacterial agent that works by releasing formaldehyde in the urine, which kills bacteria that may be present in the urinary tract. sodium salicylate helps to keep the urine acidic, which also helps to prevent bacterial growth. benzoic acid is added to the formulation to increase the solubility of methenamine in urine.