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Fosfomycin

Fosfomycin is used to treat urinary tract infections. Learn how to use the medication, its common side effects, special precautions to watch out for, and more.
  • Article last reviewed 19 January 2026
  • 5 mins read

What is this medication for?

It is an antibiotic used to treat urinary tract infections caused by bacteria.

How should I take or use this medication?

  • Do not stop taking your medication without first checking with your healthcare professional. This is to prevent bacterial resistance to the antibiotic.
  • This medicine should be taken on an empty stomach one hour before or two hours after meals.
  • Ideally, this medication should be taken before bedtime after emptying the bladder.
  • The contents of a sachet should be dissolved in 90-120mL of cool water (do not use hot water) and taken immediately after preparation.

What should I do if I forget to take or use this medication?

This section is not applicable as fosfomycin is a single-dose administration and need only be taken once.

What precautions should I take when taking or using this medication?

Inform your healthcare professional if: 

  • You are allergic to this medication or any of the other ingredients of this medication.
  • You are pregnant, or planning to become pregnant, or breastfeeding
  • You are taking any other medications, including supplements, traditional medications, and herbal remedies.
  • You have severe chronic kidney disease and/or are undergoing hemodialysis

What are some common side effects of this medication? ​

This medication is generally well tolerated. Occasional nausea, diarrhoea, heartburn, headache, and less frequently skin rash have been reported. These side effects usually improve quickly on their own without treatment.

What are some rare but serious side-effects that I need to seek medical advice immediately? 

The symptoms of a drug allergy include one or more of the following: 

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take or use this medication?

Avoid taking metoclopramide when you are taking this medicine as it may reduce the efficacy of fosfomycin. Consult your healthcare professionals for advice on the suitability of this medication with your other medications.

How should I store this medication?

Store in a cool and dry place in the original packaging, away from direct sunlight. Keep this medication away from children. The contents in the sachet should only be dissolved in water immediately before use.

How do I throw away this medication safely? ​

Pack the medication into a bag and bring it back to the pharmacy where you received the medication from. 

Disclaimer

Please take note that the above is not a complete list of all possible side-effects. If you have any concerns about your medication or if you have other side-effects that you think are caused by this medication, please consult your doctor or pharmacist. If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (NHG Health, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.