Question: I have a couple of questions: -I had just started to take Bactrim (for a small reoccurring nose infection) last Saturday. On Monday I was tested for STD's and the test came up negative. Would the Bactrim cause a False-Negative test result? The Dr was not aware of the Bactrim I started to take (I was on it just 2 days prior). He put me on a single dose of Zithromax 1g right away (my symptoms were burning when urinating, a little redness on the tip of my penis and just a very small clear discharge fluid. I'm presently 6 days out from taking this).

After the negative STD test results came back (two days later), he took some more urine and swab samples, then put me on Septra, thinking it is more of a UTI problem. He tested me for some UTI bacteria and Trichomoniasis this time. (I'm 4 days into taking this right now).

The second round of tests have all come up negative as well for bacteria and STDs.

The Doctor told me that the tests are extremely sensitive and very accurate even with the presence of antibiotics and it would probably be a waste of $ to get another test. With the 2 types of antibiotics I'm on (I stopped taking the Bactrim) he says I should be covering a very wide spectrum of bacteria. He says to keep taking the Septra and see if it gets better in a few days, if not, to go see a Urologist to see if its a urethral problem or to rule out prostate problems.

The symptoms have not changed and have been steady for 1 week now. It only bothers me when urinating, every thing else is fine (I do not have a need to urinate more often, no sores, no itching... just the redness on the tip, burning urination, & the small clear discharge). The reason for the STD test, is that I had sex with a condom, but unprotected oral sex with a woman I did not know at a bachelor party. The symptoms started about a week after the encounter (exactly two weeks ago). I am just worried this is an undetected STD.

-Should I get another STD Test (even though I'm still on these 2 antibiotics)?
-If he's right, what else could it be?

I need some input and direction at this point.

Thank you, -T

Thank you, your answer is most helpful.

If I take another urine test tomorrow (as I mentioned before I have taken two: I took the STD urine test first, and the second urine test was to look at any other bacteria the doctor could find.. both came back negative) will the current antibiotics that I'm almost done with (zithromax & septra) have any effects on another urine test?

Thank you!