Urea is in a multitude of skin care products as well as eye products.  Murine is simply urine plus an M.  I have washed out my eyes with fresh undiluted urine with a great relief from soreness.  So, as far as long term effects are concerned there should be no problem.

I used fresh urine topically for a number of months with no "ill" effects but discontinued using it on my hair/scalp because of the lingering odor no matter how much I tried to shampoo it out.  Even though that smell was very faint, I did not like it.  What I was trying to address was the dandruff and my pre-cancerous skin condition which required me to go in and have spots burned/frozen off every few months.  I was also trying to stop my athlete's foot condition.  For me, topical application did not really help either condition.

It wasn't until I began ingesting my fresh urine that both conditions improved significantly - in fact, haven't been bothered with athlete's foot in several years and my scalp is much better.

If you decide to go that route, go slow - a couple of teaspoons a day at first building up to as much as you wish.  The taste will significantly improve the longer you ingest it.  The book "Your Own Perfect Medicine" recommends a tablespoon of urine but I find that to be much to little for good effect.   You can read the important part of that book at the link below.  (Don't buy it - it's overpriced.)  It took me a year to take my first sip.   It wasn't until I watched the video "Urine: Good Health" where I watched many others from HIV positive, to firemen, to nuns, and even medical doctors talk about it.  The fireman like me had his athlete's foot clear up in a week from drinking his pee.  The nuns had all sorts of benefits and the HIV positive guy quit all medications and was feeling better and gaining weight.  Don't knock it, it works.

http://www.shirleys-wellness-cafe.com/urine_martha.htm