How is Non-Gonoccocal Urethritis (NGU) Treated?

This is a photomicrograph of a Gram-stained urethral exudate sample from a male who presented with a case of urethritis. In this particular view, what turned out to be numerous intracellular Gram-negative Neisseria gonorrhoeae diplococci bacteria were evident. Gram-stain is a histochemical technique used by microbiologists to differentiate microorganisms into two large groups, that of Gram-negative, or Gram-positive bacteria. Gram-positive bacteria stain a dark violet-blue, for the crystal-violet stain binds to the exterior cell wall of these organisms. On the other hand, Gram-negative bacteria bind with the counterstain, in this case, the safranin or fuchsin stain. This technique is yet another method by which the trained laboratorian identifies pathogens, in order to come to a diagnostic conclusion. Image courtesy CDC/Dr. Norman Jacobs, 1974. Smith Collection/Gado / Getty Images

Question: How is Non-Gonococcal Urethritis (NGU) Treated?


Most cases of Non-Gonococcal Urethritis (NGU) are undiagnosed chlamydia infections. Therefore, the first line of treatment for NGU is the same as the treatment for chlamydia.

If that NGU treatment doesn’t work, and you took all your medication as instructed, your doctors need to investigate further. The next step is usually for them to check you for a trichomoniasis infection. If that test is negative, you may not get a clear answer. (Often NGU is caused by mycoplasma, but that is only rarely tested for)

If your doctor can’t identify what the source of the infection is, they will generally treat you with one of the drugs below. This is because some of the bacteria that cause urethritis can be difficult to identify. Therefore, treating NGU this way is an effective way to eliminate the most common suspects.

Note: The drug regimens below are taken from the Centers for Disease Control 2015 STD treatment guidelines. Remember that only your doctor can say which treatment is right for you.

Recommended Regimens for Initial NGU Treatment
Azithromycin 1 g orally in a single dose
Doxycycline 100 mg orally twice a day for 7 days Alternative Regimens
Erythromycin base 500 mg orally four times a day for 7 days
Erythromycin ethylsuccinate 800 mg orally four times a day for 7 days
Levofloxacin 500 mg orally once daily for 7 days
Ofloxacin 300 mg orally twice a day for 7 days

Sometimes these treatments are ineffective. That is often because the infection is caused by a fungal or parasitic infection, such as trichomoniasis. (Sometimes the parasitic infection is in addition to a bacterial infection!) Therefore, if the initial treatment fails, doctors will try other options.

Recommended Regimens for Men with NGU Where Initial Treatment Was Not Successful

Metronidazole 2 g orally in a single dose
Tinidazole 2 g orally in a single dose
Azithromycin 1 g orally in a single dose (if not used for initial treatment)
Moxifloxacin 400 mg orally once daily for 7 days (if azithromycin was used for initial treatment.) 

The azithromycin and moxifloxacin are used because they are more likely to be effective against mycoplasma than some other medications. The moxifloxacin, in particular, is a relatively new recommendation. By the time the 2015 treatment recommendations were released, mycoplasma were considered to be a major cause of NGU. Therefore, aiming treatment at mycoplasma was though to be important after an initial treatment failure. However, CDC has found that higher dose azythromycin is not helpful in treating mycoplasma. That's why they recommend moxifloxacin rather than a second round of azithromycin treatment for NGU

In contrast, metronidazole and tinadazole are used to treat possible trichomoniasis infections. Testing is not universally available for this infection in men. 

Please Note: You should generally stop having sex while on treatment. This reduces the likelihood that you and your partner will pass an infection back and forth. Any regular sexual partner should also be referred for testing & treatment when you are diagnosed with an STD

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