I’ve read that foreigners may not bring prescription medications into Turkey. Is that accurate?
No, that's absolutely not true. I would suggest reading through this thread from last year, which should answer your question in detail.
Here is what the US State Department says:
If traveling with prescription medication, check with the government of Turkey to ensure the medication is legal in Turkey. Always carry your prescription medication in original packaging with your doctor’s prescription. Some medications may be unavailable in Turkey.