Can I buy a replacement Structum on the same prescription?

Up to @Ania N:

A dietary supplement will not be as effective as a drug. Drugs must go through a rigorous registration process, including clinical trials confirming their effectiveness and safety. Dietary supplements are treated as food and are not subject to such strict controls. In the case of a prescription issued by a doctor, you should not replace the prescribed drug with a dietary supplement yourself. Such a change requires consultation with a doctor.

We wrote more about it here:

https://www.gdziepolek.pl/artykuly/czym-roznia-sie-leki-od-suplementow

The replacement of Structum with Cartexan is similar. Both preparations are prescription drugs, contain the same active ingredient - chondroitin sodium sulfate and have similar indications in the symptomatic treatment of osteoarthritis of the knee and hip. Note, however, that Cartexan contains a lower dose of chondroitin, i.e. 400mg, while Structum contains 500mg. Such a change in therapy should also be consulted with the attending physician.

If you are not able to make a face-to-face visit, I attach a link to the online teleconsultation:
https://www.gdziepolek.pl/telekonsultacja/z-ortopeda

And will the supplement be as effective as the drug? A doctor usually prescribes a drug, can I buy Cartexan with the same prescription? I saw in your information that it is also a drug and a substitute for Structum?