Can you use expired Bactrim for UTI? 

Can you use expired Bactrim for UTI?

No, you should not use expired Bactrim for an active UTI. Expired antibiotics often fail to attack the growth of infection-causing bacteria with full force as these meds start to lose their effectiveness. 

It might take some time, yes, and Bactrim will most likely work if it has recently expired, but I would still not recommend using an expired antibiotic for a symptomatic UTI. 

Expired Bactrim is not good for any kind of infection. So, make sure you avoid using expired medications and reach out to your doctor to get a new prescription.

What are the possible dangers associated with the use of expired Bactrim? 

Expired Bactrim for an active UTI can cause some harmful effects. Some of the possibilities include:

Worsening of UTI

UTI is an infection that can occur in any part of your urinary tract. These bacteria continue to thrive if a powerful antibiotic is not used to disrupt their growth. 

Untreated or improperly treated UTIs can cause bacteria to enter your bloodstream, which could lead to blood infection. This is why you should never use expired Bactrim for the treatment and management of UTI. 


The use of expired Bactrim can also lead to antibiotic resistance in your body, which can help bacteria adapt and survive the presence of Bactrim (2). 

This can cause complications and delay your recovery and the bacteria will fight to survive even if you start using an unexpired Bactrim at this point. 

Adverse drug reactions 

The use of expired Bactrim can also cause some unwanted side effects, without benefiting you. Some of the common ADRs include nausea, vomiting, diarrhoea, weakness, abdominal pain, swelling or tenderness in different parts of the body, etc. In rare cases, expired Bactrim can trigger a severe allergic reaction. 

What to do if you have used expired Bactrim? 

If you have accidentally taken a dose or two of expired Bactrim, the drug will not affect your health. Bactrim usually is not harmful to your body on its own, but its ineffectiveness can cause the worsening of your infection which could generally make you feel sick. 

It’s best to talk to your healthcare provider about your symptoms associated with UTI and stick to the prescription antibiotic only. Do not use Bactrim, expired or unexpired, without your doctor’s approval. 

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U.S. Food and Drug Administration. Don’t Be Tempted to Use Expired Medicines [Internet]. Silver Spring (MD): U.S. Food and Drug Administration; 2021 [cited 2022 Oct 22]. Available from:


Abushaheen MA, Muzaheed, Fatani AJ, Alosaimi M, Mansy W, George M, Acharya S, Rathod S, Divakar DD, Jhugroo C, Vellappally S, Khan AA, Shaik J, Jhugroo P. Antimicrobial resistance, mechanisms and its clinical significance. Dis Mon. 2020 Jun;66(6):100971. doi: 10.1016/j.disamonth.2020.100971. Epub 2020 Mar 20. PMID: 32201008. Available from: