title: I'm taking Zocor to help lower my cholesterol. The directions say to take it at night. My friend takes Lipitor, but doesn't have to take it at night. Why the difference?
mesh_terms: D000924:Anticholesteremic Agents / Q000008:administration & dosage*; D000069059:Atorvastatin; D019454:Chronotherapy; D006538:Heptanoic Acids / Q000008:administration & dosage*; D006801:Humans; D011758:Pyrroles / Q000008:administration & dosage*; D019821:Simvastatin / Q000008:administration & dosage*
chemical_list: D000924:Anticholesteremic Agents; D006538:Heptanoic Acids; D011758:Pyrroles; D000069059:Atorvastatin; D019821:Simvastatin