Definately NOT, because it is stealing! All medication administration must be prescribed by a doctor. No one can give/ adminstrate/ inject any medication to another person without an order. If your sister does that, she is going to put her license on risk. For 鎮定劑... if she steals it from her work site, she is going to have police arrest her.. that is DDA (Dangerous drug).
參考: as a Nurse for 14 years, licensed in HK, Australia and USA