Every step from warehouse to pharmacy is measured and recorded, but on the way from pharmacy to home the medicine sets off on a journey with no record at all. The cost of the chain can be lost in that last half hour, because a product that must be kept at 2-8 °C can warm up or freeze.
Do not run other errands on the way, keep the medicine with you and do not leave it in a car parked in the sun. The insulated bag and cool pack a pharmacy provides make a difference on a short trip; keep the medicine away from the pack, because the product information for medicines such as insulin glargine (EMA) says not to freeze it and not to place it next to the freezer compartment or a freezer pack.
On arrival, keep the medicine in the fridge as the package instructs. If it looks warm, frozen, in damaged packaging or of unknown transport history, do not decide yourself whether to use or discard it; set it aside and ask the pharmacist.
On a flight, carry the medicine in the cabin bag. Turkish civil aviation rules (SHGM) make an exception to the liquid limit for medicines: you show a prescription or health report with your identity and the medicine is in its original packaging. The temperature of a minibar fridge at your accommodation is uncertain, so measure it before you put the medicine in.
The pharmacy can give this information as a written card: storage condition, how to carry it, the placement step at home and whom to call if there is a problem. A card matched to the product name and presentation lasts longer than general advice.