Consult the doctor at least a week or two in advance in order to see that medical condition is stable. If not, investigations and titration of treatment can be done in time.
Keep a typed list of all the medications including the generic names, as doctors abroad may not know about the brand names of Indian medicine.
Keep sufficient / extra stocks of medicines, you may not be able to purchase medicines without a prescription of a doctor of the country you are visiting. They may be far more expensive than in India.
Keep medicines like cash, two or three different bags, so even if one bag is lost or delayed you are not stuck without medicines.
Buy travel health insurance to cover unanticipated medical emergencies.
Learn about local seasonal prevailing infections in the country of travel and see if you need any immunisation to protect yourself.