Hi Thanks for posting your query on HCM. I appreciate your concern for the ankle swelling during travelling. It is not safe to take Lasix for the treatment of swelling of the ankles during travelling. Swelling around the ankles is commonly seen during travelling and it is harmless. it is due to prolonged sitting on chairs with the legs dangling over the edge of the chair for a long period causes blood to pool in your leg veins. The position of your legs when you are seated also increases pressure in your leg veins. This contributes to foot swelling by causing fluid to leave the blood and move into the surrounding soft tissues. To relieve ankle swelling during travelling: Wear loosefitting clothing Take a short walk every hour or so if possible Flex and extend your ankles and knees frequently while you re seated Shift your position in your seat as much as possible, being careful to avoid crossing your legs Drink plenty of fluids to prevent dehydration Avoid alcohol and sedatives, which could make you too sleepy or unsteady Since you are already taking medications for high BP, the BP may fall down drastically if you take Lasix to reduce the ankle swelling. Hence it is not advisable to take Lasix to reduce the swelling, which usually subsides by its own. Hope the suggestions given above could of great help in reducing the ankle swelling during travelling. Take care. A feedback is highly appreciated.