While you’re abroad is not the time to suddenly realize you ran out of your prescription!
If you have a condition that requires regular medication, bring an extra quantity with you and pack it in your carry-on, just in case your checked luggage gets lost. Just remember to keep it in its original container and clearly labeled — you don’t want to create the impression you’re carrying drugs which haven’t been prescribed to you. In fact, you should check with the local embassy to make sure that your medication is acceptable to carry into the country. Some countries may consider your prescription medication to be illegal. Bring a letter from your doctor listing your medications and explaining why you need them. Doing your research and having a letter can help prevent any misunderstandings along the way.
Bring extras of any medical necessities you need, like contact lenses or glasses. You might want to pack a pair in both your carry-on bag and your checked luggage, just to be safe.
If you have allergies to certain medications, foods, insect bites, or other unique medical problems, consider wearing one of those “medical alert” bracelets and carry a letter from your doctor explaining required treatment if you become ill. It might not be the coolest piece of jewelry you wear, but it could save your life.