Why do I need to know my blood pressure to get an ED prescription?

ED tablets affect blood vessels and can be unsafe with very high or very low blood pressure, certain heart conditions, or when taken with some other drugs (for example nitrates). A reading from the last six months helps a prescriber judge whether tablets are likely to be safe. If you do not know your blood pressure, you can usually have it checked free or at low cost at a pharmacy, GP practice, or wellbeing event.