Hi, I travel to Turkey several times a year and carry quite a few medicines including pain killers. I have never been stopped ever. I do carry a letter because I am diabetic and carry needles but the letter only mentions the needles and diabetic medication. Only once have they been interested in seeing the letter and that was on my way out of the country. The girl clearly couldn't read it lol, but she looked anyway.
I do carry a repeat prescription leaflet - the ones you get attached to the prescription and I do make sure all medicines are in their boxes with my name on. Having said all that no one has ever stopped me or looked at them.
It may be worth you knowing that some medicines cannot be bought in Turkey. In the past Codeine was one of these and I thought that was still the case but someone recently told me that had changed, but I am not sure. I walk in and out with co codamol every visit.

As JMK says - keep them in their original packs with a copy of the prescription. I always carry them in my hand luggage so that I know they are not going to get lost as some are difficult to replace. Have never taken a GP's letter and have never had them checked either. Hope you have a good time.

The following is from the Turkish Embassy website:-

http://www.turkishembassy.com/ii/K/FAQ.htm#3

Can I bring medication to Turkey?

Medications in labeled pharmacy bottles can be brought into Turkey. Injections needles needed for those with diabetes are also allowed, but it would be helpful if you have a doctor’s note or copy of your prescription with you. Wheelchairs of any sort are allowed into Turkey, along with breathing mask or other protective medical clothing.

HTH

My dad takes quite a lot of medicines and he just makes sure he has a copuy of his prescription.

Thanks to all for your advice this puts our mind at rest