title: Tadalafil and vardenafil.
authors.forename: Katherine
authors.initials: K
authors.lastname: Neumeyer
authors.forename: Peter
authors.initials: P
authors.lastname: Kirkpatrick
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases; D002243:Carbolines / Q000737:chemistry / Q000494:pharmacology*; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D017277:Drug Approval; D007172:Erectile Dysfunction / Q000188:drug therapy; D005544:Forecasting; D006801:Humans; D007093:Imidazoles / Q000737:chemistry / Q000494:pharmacology*; D007880:Legislation, Drug; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D010727:Phosphoric Diester Hydrolases / Q000187:drug effects; D010879:Piperazines / Q000737:chemistry / Q000494:pharmacology*; D011687:Purines; D000068677:Sildenafil Citrate; D013450:Sulfones; D000068581:Tadalafil; D014227:Triazines; D000069058:Vardenafil Dihydrochloride
chemical_list: D002243:Carbolines; D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; D000068581:Tadalafil; D000068677:Sildenafil Citrate; D010727:Phosphoric Diester Hydrolases; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; C517381:PDE5A protein, human