“Clonidine accumulation in lung alveolar A549 cells was found to be temperature- and pH-dependent; it was saturable, … affinity constant (Km) value of 569.4 μM. Various pneumophilic drugs, including amitriptyline, verapamil, propranolol, chlorpromazine, imipramine, and quinidine, … clonidine uptake in A549 cells, in a … at least some of them.”