Xylazine's action can be seen usually 15 to 30 minutes after administration and the sedative effect may continue for 1–2 hours and last up to 4 hours. Once xylazine gains access to the vascular system, it is distributed within the blood, allowing xylazine to perfuse target organs including the heart, lungs, liver, and kidney. In nonfatal cases, the blood plasma concentrations range from 0.03 to 4.6 mg/L. Xylazine diffuses extensively and penetrates the blood brain barrier, as expected due to the uncharged, lipophilic nature of the compound.