Don't strain yourself by trying to see everything at once. While traveling or sightseeing, keep to your own pace and don't let tour guides or others hurry you. After all, this is your vacation. Carry a full supply of all your medicines and any medication you might need.
Some drugs are difficult to obtain in certain countries and expensive.
Make sure you know the generic names of your medications, as brand names vary from country to country. Carry copies of your prescription with you. In case of emergency, you can obtain extra medications with it. Always remember to ask if there is a senior discount. A lot of places that offer senior discounts do not advertise them prominently.