Online Pharmacy 4U sells Istin online for high blood pressure. You can buy this medicine in tablets of 5 mg and 10 mg. Fill out our online medical form to have one of our doctors review your order. Our UK pharmacy will dispatch your medication the next day if your order is approved by 3pm on weekdays. Please note: a recent blood test is required to purchase this item or proof of a recent blood test, we can accept a proof of prescription from your GP within the last 3 months, we can also accept a screen shot of your NHS app. What counts as proof of a prescription? Use the print out of your medication provided by your pharmacy when you collect your medication. Ask for a print out of your prescription, or patient summary print out from the surgery