No problem... Just go to the nearest big and active Pharmacy. If they have the medicine you normally take they will sell it to you.
If they do not have that exact medciine, hopefully tney can figure out something close to what you nomally take and sell that to you.
I would go to a big Pharmacy, like "CAFAM" in the "EXITO" and "CARULLA" stores or to a Drogas La Rebaja.
The people who work in Pharmacies here are usually very knowledgeable.
Normally, you do not require a written prescription to buy prescription medicines here, although there are exceptions to that.
The "worst" case would be to ask which Private Hospital near to where you are is the best private hospital in that area and go there and make an appointment to see an M.D. there, who can, hopefully, prescribe something very close to what you are taking. Better yet, a Pharmacist in the hospital.
Other big pharmacies are Pharmatodo, Colsubsidio, Locatel.
If you have the molecule names of your medicines, better, it will help the pharmacist, or the MD, to know how to replace them with local brands.
If you don't know, Google will help you find this out.