Sildalist is a medication that combines two active ingredients: sildenafil citrate and tadalafil. Sildenafil citrate is the active ingredient in Viagra, and tadalafil is the active ingredient in Cialis. Both sildenafil and tadalafil belong to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors, which are used to treat erectile dysfunction (ED) by increasing blood flow to the penis during sexual stimulation.