Thanks for posting your query.
With the available described symptoms, there appears to be high chances of decreased gastrointestinal motility due to diabetes
or deranged renal function test (as you are also suffering from kidney disease).
You should take proper amount of fluids with along with high fibres diet.
Isapghula is also a form of high fibre diet.
There may also be possibility of irritable bowel syndrome
and relief of pain after taking Meva-C suggest the diagnosis.
You should take 25 mg of Serta as high dose may at times causes sudden drowsiness
. Dose may be raised in future with sequential visits.
You should also take those laxatives which increases gastrointestinal motility such as dulcolax
DR. Mayank Bhargava