Inclusion Criteria:  Inclusion criteria for hypothermia group (University Clinical Centre Sarajevo)  signed parental informed written consent newborn with GA ≥36 weeks newborn to whom amikacin is administered by intravenous route for clinical indications newborn with perinatal asphyxia treated with hypothermia  Inclusion criteria for control group (University Clinical Centre Tuzla)  signed parental informed written consent newborn to whom amikacin is administered by intravenous route for clinical indications newborn with GA ≥36 weeks  newborn with perinatal asphyxia defined following Bristol hypothermia protocol from 2015  Apgar score of ≤5 at 10 minutes after birth OR Continued need for resuscitation, including endotracheal or mask ventilation, at 10 min after birth OR Acidosis defined as either umbilical cord pH or any arterial, venous or capillary pH within 60 min of birth pH<7.00 OR Base deficit ≥-16 mmol/L in umbilical cord blood sample or any blood sample within 60 minutes of birth (arterial or venous blood)  Non-inclusion criteria for both groups  no parental informed consent the presence of congenital hepatic or renal pathology no central venous or arterial line in situ for non-invasive blood sampling procedures  Exclusion criteria for both groups  parental informed consent withdrawal the occurrence of clinical reasons to stop blood sampling