Brief Answer:
5mm stone should pass down through ureter.

Detailed Answer:
Hello,

Thanks for your query. Based on the facts that you have posted it appears that your father is known to get urinary stones frequently. Now he has severe pain due to 5 mm stone .

I shall be happy if you can post me few more details to help me in making comments on your problem.
1) Is stone in Kidney or Upper ureter?
2) What is the grade of Hydronephrosis (Back Pressure changes in kidney) due to impaction of stone reported on ultrasound scanning ?.

Normally stone of a size of 5mm pass down easily through ureter but it is very difficult to predict how long it will take to pass down through ureter into bladder. It depends upon the oedema at the site of impaction .

Please ensure he drinks more water to produce more urine. This will facilitate to pas the stone early. I would also give him broad spectrum antibiotics like Cefexime to prevent infection and anti spasmodic like Cyclopam twice daily. Smooth muscle relaxants like Drotaverine twice daily will help to relax smooth muscles in ureter that will help to pass down the stone smoothly and without pain.

Hope he will pass the stone within couple of days.

Hope I have answered your query ,please feel free to ask if you have more questions ,
I shall be happy to help you

Thanks and Regards.
Dr.Patil.

---