How long does it take for antibiotics to work on urinary tract infections?

I've been having very bad urinary tract infection for about 1 week (with blood every time I go to the bathroom).I took trimethoprim for 3 days but it didn't get better so the doctor gave me nitrofurantoin..today is the second day and its not improving. How long does it normally take to get better???

Nitrofurantoin (macrodantin or macrobid) can be used to help
prevent urinary tract infections, but are not very successful when the infection has had time to grow stronger. Did your Dr perform a urinalysis? I hope so. You really need to know what kind of bug you are working with. If an antibiotic is working, you should start feeling better in three days. Otherwise, go back to your doctor!!
I was given this form of drug by my gynecologist for frequent
urinary tract infections. It never worked. I was miserable and eventually went to see a Urologist. He suggested that the above drugs are good when you need to "wash" out the bacteria in your
urethra and bladder BEFORE they have a chance to attach to the walls of either. (this is done for people who have frequent uti's-you take one a day as a preventative) Once attached, the bacteria can grow and eventually move up into your kidneys if you can't get on a medication capable of killing the bug. I just really think that you need to make sure your Dr did a urinalysis-
and insist that he puts you on a strong medication known to kill
the bacteria that is found! Good Luck! I can so relate!!

Have them do a urine culture so they can find out what bug is causing it and prescribe the proper medication.

Usually those drugs really begin to help quickly. Definitely call your doctor today and let him know the new medication isn't helping.

Bless your heart! I hope you feel better soon- I know those things are miserable!

Sometimes if you have had the urinary tract infection for a while and sometimes this happens by the time you start having blood in your urine, it is extremely difficult to clear up. I had one for 3 weeks, and the last antibiotic I was put on, the doctor told me that if it did not clear up, I would be hospitalized for it. So it may take 3 weeks for it to go away, with having to take 3 different antibiotics to clear it up.

I am not a doctor but every time they prescribed they always tell the patient that the antibiotic takes effect after 3 days. It means it on this day the medicine starts to weaken the bacteria and it will another 4 days to really them. If no effect yet after taking the med. for 3 or more days, I think you can request the doctor to presecribe a higher dose and higher level of antibiotic.

Nitrofurantoin (Macrodantin) is taken for 10 days. You need to give it at least 48 hours. I believe you are taking a once daily dose. Don't skip any doses and take it all. Drink 3 liters of water a day and omit cranberry juice for the time being. (I guarantee that you'll be advised to drink this by someone who answers this question) Someone else brought up a very good point - has your urine been cultured? Did you give a urine specimen about 2 weeks ago? If not, speak to your doctor on Tuesday about running a STAT urine C & S. You can quote me if you like.

48 hour at the most. try some cranberry juice. that will help A LOT!!!

The problem with treating UTI, is getting the antibiotics to the site of infection. Most of them are too large to enter the urinary tract through the glomerulous, so it takes longer than normal for any improvement to be seen. I assume that they took a culture sample - if they didn't it could be that the bug is tollerent to nitrofurantoin.

I have had three UTIs in the past year. The only drug that has worked is Cipro. If possible get the extended release form of Cipro. Must drink LOTS of water with Cipro. Also, in the future try to be tuned in to other symptoms before you have blood, etc. Frequent urination, feeling like you MUST go NOW, and pain in the very low abdomen...right by the pelvic bone in front of the bladder, and chills as a sign of your body trying to fight it. Now that I know the early symptoms, I have been able to make it into the Dr. before there's blood and all that. It's still super painful, but at least the antibiotics get in there before it's severe or goes to the kidneys. Definitely get your Dr. to do a culture...you don't want to mess around with this.

I had UTIs on a regualar basis for 2 years and had a problem getting rid of it. Make sure your Kidney and Bladder is ok. I found out that I had renal cancer stage 3

Good luck!

Antibiotics take 48 hours to start taking effect.

it takes about 5 to 7 days for them to really start working but it is possibly for them to start soon if after a week it done help go back to the doctor and ask why they have not started working.