There are a range of interactions of Benadryl with other medications that should not be overlooked. While some may think of Benadryl as simply an over-the-counter remedy, its drug interactions can have serious consequences if taken without medical advice. Patients with kidney disease usually have a cocktail of prescription medications being taken, such as blood pressure drugs like angiotensin receptor blockers or angiotensin converting enzyme inhibitors. So, it is important to consider each one when it comes to possible medication interactions. Hence, it's best to consult your doctor before taking any medication - even something as seemingly harmless as Benadryl!