title: Letter: Clonidine withdrawal and blockade.
mesh_terms: D003000:Clonidine / Q000627:therapeutic use*; D004357:Drug Synergism; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D011433:Propranolol / Q000627:therapeutic use*
chemical_list: D011433:Propranolol; D003000:Clonidine