Pharmacy Guide
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Pharmacy Guide
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Hiprex 1 g Tablets
⚠ This medicine appears to have been discontinued
The electronic medicines compendium (emc) no longer publishes a Summary of Product Characteristics for this product, which usually means it is no longer marketed in the UK. The patient leaflet below is kept for reference, but the product may not be available.
If you were prescribed this medicine, other products containing Methenamine hippurate may still be available. Do not stop your treatment — ask your pharmacist or GP what to use instead.
What it is and what it is used for
for Hiprex contains the active substance methenamine hippurate and belongs to a group of medicines called anti-bacterials. These work by killing many different types of bacteria which cause infections. Hiprex is used to treat infections of the urinary tract and stop them from coming back. The urinary tract is a collective name for the parts of the body that produce, store and transport urine. These include the kidney, bladder and tubes called the ureter and urethra. It is also used to avoid urinary tract infections in patients with catheters from their bladders (a tube that helps with incontinence) and in people undergoing certain medical procedures.
What you need to know before you take it
e Hiprex Do not use Hiprex if:
- You are allergic to methenamine hippurate or any of the other ingredients of this medicine (listed in section 6)
- You are taking antibiotic medicines called sulphonamides. These can damage your kidneys when taken at the same time as Hiprex
- You are severely dehydrated
- You have serious problems with your kidneys
- You have problems with your liver
- You have gout
- You have a condition called metabolic acidosis (a chemical imbalance in the blood). If any of the above applies to you, talk to your doctor or pharmacist. Warnings and precautions Talk to your doctor or pharmacist before taking Hiprex if:
- You have any kinds of problems with your kidneys. Tell your doctor if you are taking any of the following medicines:
- Medicines to make your urine less acidic such as potassium citrate and acetazolamide. These can stop Hiprex working properly.
- Any other medicines, including medicines obtained without a prescription.
Pregnancy, breast-feeding and fertility If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.
How to take it
Hiprex Always take Hiprex exactly as your doctor or pharmacist has told you. You should check with your doctor or pharmacist if you are not sure. Important: Your doctor will choose the dose that is right for you. Your dose will be shown clearly on the label that your pharmacist puts on your medicine. If it does not, or you are not sure, ask your doctor or pharmacist. Adults The recommended dose is one tablet twice a day. If you have a catheter your doctor may increase your dose to one tablet three times a day. Use in children Not for children aged under 6. Children aged 6 – 12 years the recommended dose is half a tablet (500mg) twice a day. Method of administration The tablets can be broken in half. If you find it particularly difficult to swallow them, the tablets may be crushed and taken with a drink of milk or fruit juice. If you take more Hiprex than you should If you accidentally take more Hiprex than you should, you might be sick or see blood in your urine. Drink plenty of water and immediately go to the nearest hospital casualty department or your doctor. Your doctor may give you another medicine to stop you being sick. If you forget to take Hiprex Do not take a double dose to make up for a missed dose. Simply take your next dose as planned. If you stop taking Hiprex Your doctor will tell you how long to take your medicine for. Do not stop taking Hiprex without first talking to your doctor. If you have further questions on the use of this medicine, ask your doctor or pharmacist.
Possible side effects
Like all medicines, this medicine can cause side effects, although not everybody gets them. You may experience the following: Uncommon: may affect up to 1 in 100 people
- Rashes
- Itching
- Stomach irritation
- Bladder irritation usually seen as a burning sensation and pain on urinating
- Nausea
- Vomiting
Not known (cannot be estimated from the available data)
- Diarrhoea, abdominal pain Reporting of side effects If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.
How to store it
Hiprex Keep this medicine out of the sight and reach of children. Do not use Hiprex after the expiry date which is stated on the bottle. The expiry date refers to the last day of that month. Store Hiprex below 30 °C, with the bottle lid tightly closed in its original carton. Medicines should not be disposed of via wastewater or household waste. Return any medicine you no longer need to your pharmacist.
Contents of the pack and other information
What Hiprex contains The active substance is methenamine hippurate. Each tablet contains 1 gram. The other ingredients are magnesium stearate (E572), povidone and colloidal anhydrous silica. What Hiprex looks like A white to creamy-white oblong shaped tablet coded HX with break line on one face and break line on the other face. Hiprex comes in a glass bottle which contains 60 tablets. Marketing Authorisation Holder: Viatris Products Limited, Station Close, Potters Bar, EN6 1TL, United Kingdom. Manufacturer: Fine Foods & Pharmaceuticals N.T.M. S.p.A. Via Grignano, 43, 24041 Brembate (BG), Italy Mylan Hungary Kft. Mylan utca 1, Komarom 2900, Hungary This leaflet was last revised in October 2025. If this leaflet is difficult to see or read and you would like it in a different format, please contact Viatris Products Limited, Station Close, Potters Bar, EN6 1TL, United Kingdom.
Frequently asked questions about Hiprex 1 g Tablets
How do I take Hiprex 1 g Tablets?
Hiprex 1 g Tablets comes as tablet containing 1g. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.
What is the active substance in Hiprex 1 g Tablets?
The active substance in Hiprex 1 g Tablets is methenamine hippurate.
Are there equivalent medicines to Hiprex 1 g Tablets?
Medicines with the same active substance, strength and form include: Methenamine hippurate 1 g tablets, Methenamine hippurate 1 g tablets. They are interchangeable only if your prescriber or pharmacist says so.
Where does this information come from?
This leaflet reproduces the patient information leaflet approved for Hiprex 1 g Tablets, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.
Can I get Hiprex 1 g Tablets without a prescription?
Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.
About this leaflet
The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.
- Source: electronic medicines compendium (emc), Datapharm
- Active substance: methenamine hippurate
- Official document: view the original leaflet on emc →
⚕For healthcare professionals — Summary of Product Characteristics (SmPC)Full SmPC: dosage, interactions, contraindications, warnings+
4.1. Therapeutic indications
Hiprex is indicated in the prophylaxis and treatment of urinary tract infections:
1. As maintenance therapy after successful initial treatment of acute infections with antibiotics.
2. As long-term therapy in the prevention of recurrent cystitis.
3. To suppress urinary infection in patients with indwelling catheters and to reduce the incidence of catheter blockage.
4. To provide prophylaxis against the introduction of infection into the urinary tract during instrumental procedures.
5. Asymptomatic bacteriuria.
4.2. Posology and method of administration
Posology
Adults: 1g twice daily.
In patients with catheters the dosage may be increased to 1g three times daily.
Paediatric population:
Children under 6 years: Not recommended.
Children: 6-12 years: 500mg twice daily.
Older people: No special dosage recommendations.
Method of administration
The tablets may be halved, or they can be crushed and taken with a drink of milk or fruit juice if the patient prefers.
4.3. Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.
Hepatic dysfunction, renal parenchymal infection, severe dehydration, metabolic acidosis, severe renal failure (creatinine clearance or GFR<10 ml/min.) or gout. Hiprex may be used where mild (20-50 ml/min.) to moderate (10-20 ml/min.) renal insufficiency is present. (If the GFR is not available the serum creatinine concentration can be used as a guide.). Hiprex should not be administered concurrently with sulphonamides because of the possibility of crystalluria, or with alkalising agents, such as a mixture of potassium citrate.
4.4. Special warnings and precautions for use
None.
4.5. Interaction with other medicinal products and other forms of interaction
Methenamine hippurate should not be given/administered concurrently with sulphonamides because of the possibility of crystalluria, or with alkalising agents such as potassium citrate. Concurrent use with acetazolamide should be avoided as the desired effect of hexamine will be lost.
Depending on the type of analysing method used, methenamine can affect the determination of steroids, catecholamines and 5 hydroxyindole acetic acid from urine and give false results.
4.6. Fertility, pregnancy and lactation
Pregnancy
There is inadequate evidence of safety of methenamine hippuratein human pregnancy, but it has been in wide use for many years without apparent ill consequence. Animal studies are insufficient with respect to reproductive toxicity (see section 5.3). As a precautionary measure, it is preferable to avoid the use of methenamine hippurate during pregnancy.
Breast-feeding
Methenamine is excreted in breast milk but the quantities will be insignificant to the infant. Mothers can therefore breast feed their infants.
Fertility
There are no human data available on fertility. Data from studies in rats do not indicate any effects on female fertility, effects on male fertility have not been adequately tested (see section 5.3).
4.7. Effects on ability to drive and use machines
None.
4.8. Undesirable effects
Adverse events are listed below by system organ class and frequency. Frequencies are defined as:
Very common (≥1/l0)
Common (≥1/100 and <1/10)
Uncommon (≥1/1000 and <1/100)
Rare (≥ 1/10,000 and <1/1000)
Very rare (<1/10,000)
Not known (cannot be estimated from the available data).
Gastrointestinal disorders
Uncommon: gastric irritation, irritation of the bladder, nausea, vomiting
Not known: Diarrhoea, abdominal pain
Skin and subcutaneous disorders
Uncommon: Rash, pruritus
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
4.9. Overdose
Vomiting and haematuria may occur. These can be treated by the use of an anti-emetic and drinking copious quantities of water respectively. Bladder symptoms can be treated by the consumption of copious quantities of water and 2-3 teaspoonfuls of bicarbonate of soda.
💬 Ask about this leaflet
Ask anything about Hiprex 1 g Tablets. The assistant answers only from this leaflet — if the leaflet does not cover it, it will say so. It does not give medical advice.
Answers come from the patient leaflet published on the electronic medicines compendium (emc). They are not medical advice. Ask a pharmacist or your GP if you are unsure. For urgent help call NHS 111, or 999 in an emergency.