Turkish banks are pulling back on credit to consumers and businesses. Power plants have shut down because of the soaring cost of imported fuel. Building projects in Istanbul stand half finished after their backers ran out of money.

And, in a shopping mall beneath Istanbul’s Trump Tower, Cenap Sarialioglu says he worries he will not be able to supply customers at his pharmacy with the prescription drugs they need to stay alive.

Mr. Sarialioglu, who is also president of the Istanbul chamber of pharmacists, said he has been getting calls from other pharmacists concerned that wholesalers will cut off supplies of crucial medications because they can no longer make a profit. Drug prices are set in Turkey, so the sharp drop in the lira has made it costly to import pharmaceuticals.