How do you get rid of adenovirus urethritis? how long does it last?

There is no cure and no treatment is needed. Adenovirus is cleared by the immune system in a week or two. If you're the same person with another question about urethral pain, keeping urine dilute by drinking lots of fluids will help. You also could try one of the many over-the-counter medications containing phenazopyridine; look for Azo or other brands.

Generally Doxycycline or azithromycin are used. It gets better in about 10-14 days- depending on some factors like lduration and co morbidities.