I have been experiencing pain when urinating and ejaculating. Noticed
Hello and welcome to Ask A Doctor service.
I have reviewed your query and here is my advice.
The symptoms you are describing would most likely be due to urethritis, which is inflammation of the passage from your bladder to the head of your penis. A prostatitis is also possible, and is sometimes associated with blood in the semen, but given your symptoms of feeling itchiness from inside the penis along with possibly a clear discharge, I would be most suspicious of a urethritis at this time.
If you are sexually active, the most common causes of this would be gonorrhea or chlamydia, and then after that are less common causes such as mycoplasma genitalium. I would recommend that you get tested for these so that you can hopefully get started on treatment as soon as possible.
I hope that helps, please let me know if you have any questions about any of that and I would be glad to discuss it with you further.
Urethritis that is not sexually transmitted would be a little more unusual, so I would say that it would be important to get tested to make sure what the cause is. You probably should be evaluated for prostatitis as well with the blood in your semen. That being said, the most common organisms aside from sexually transmitted ones would include E. coli and other bacteria that commonly cause urinary tract infections, and these are normally treated with something like Bactrim or Ciprofloxacin. Amoxicillin and Cephalexin would not be ideal in this situation.
There are reports of doxycycline successfully treating a UTI but it is not usually used for that and typically they only used it if the urine culture showed that the bacteria was able to be treated with doxycycline, so I guess all I can say is that it might work, but I couldn't guarantee it since we don't have much experience treating UTIs with doxycycline. The best thing would be for you to get a urine culture so that you know what you are treating; especially as a male it is abnormal to get a urinary tract infection so I would want to know what the cause was.