Hello,
You may have 
Prostate enlargement, that is why your treating 
urologist prescribed you 
Tadalafil.
At this age, you may have Benign Prostate enlargement and it may cause disturbances in urine flow.
Both the drugs 
Losartan and Hydrochlorthiazide, very rarely cause Skin rashes and blotches but not always.
Further you may be allergic to any of the above drugs.
It may also be due to some other 
allergy or any skin infections.
You have not mentioned, where these blotches are?
As it occurs, shortly after taking these drugs, it may be due to side effects of these drugs or allergy.
But you need to get examined by your treating physician to identify the possible causes.
If he suspects it due to allergy or side effect, he may substitute some other diuretics and anti hypertensives.
Hope this helps.
Please write back for further queries.
Wishing you good health.