Urine Odor From Amoxicillin

Thanks so much for reaching out to us! A change in urine odor is certainly a possible side effect of amoxicillin but the absence of a smell doesn't indicate that the medication will be ineffective, or is a dud.

Why Does Amoxicillin Have An Odor?

Amoxicillin is known to cause urine to have a slight odor to it in many individuals due to the fact that most of the drug is excreted in the urine within 6-8 hours after dosing.

In fact, according to the prescribing information for amoxicillin, around 60% of amoxicillin is excreted in the urine unchanged (i.e. not a metabolite or a byproduct). How your amoxicillin tablets/capsules smell may very much smell like what is being excreted in the urine.

Several Factors Influence Odor

Now can be several factors that influence whether or not there will be an odor to the urine while taking amoxicillin.

First and foremost, the main factors are food and your hydration status. Food in the stomach inhibits how quickly amoxicillin is absorbed and therefore would greatly reduce a noticeable odor. Additionally, and just as importantly, the amount of liquid intake would also alter the odor of the urine. The more dilute your urine is, the less it will smell.

In addition, and this is a smaller factor, your amoxicillin may also be coming from a different manufacturer than your past medication. Different manufacturers use different inactive ingredients, and while the actual amoxicillin is no different, the other ingredients could certainly influence an odor as well. It would be relatively rare for a drug not to contain the stated amount of active ingredient. When a produced lot from a manufacturer has any flaws, there is an immediate recall issued.

We have checked the recalls for the past few months and amoxicillin has not been recalled. You could certainly check with the pharmacy that dispensed the medication just to be sure.

Final Words

As a practicing pharmacist for many years, I have seen this situation and been asked about it many times before. In all the prior cases I have seen, there has been no reduced effect of the medication. If you are concerned, I would certainly double-check with the pharmacy to make sure everything with the drug is OK and with your doctor but, as mentioned, urine odor is just a potential side effect of amoxicillin therapy.