Before you travel, it is recommended that you pack label your medications in their original containers and that you ask your doctor to write a letter for you describing all your medical conditions and needs if ne If you happen to have a heart condition, you should bring a recent copy of your electrocardiogram. 

Bring twice as many medication you need in case you lose it or it is stolen from you. It may be difficult to find the specific medication you need in that case.

Register your trip at your local Office of Foreign Affairs as a preventive measure in case of a natural disaster. 

Arrange your vaccines 6 to 8 weeks before arriving in Thailand, in case you decide to get multiple-injection vaccines such as Hepatitis A or B. The only legally required vaccine is yellow fever, but it is also recommended that you may take Rabies, Malaria, and Tetanus-Diphtheria –depending on the activities you will undertake. 

Even if you are very fit and healthy, do not travel without a health or travel insurance!