Administering a glucose drip.
Administering a glucose drip in the state of fasting does not invalidate the fast. This is because the glucose water or medicine enters the body through the veins; it does not enter through the natural orifices (pores/openings), and does not directly reach the internal cavity (Jawf). However, without a severe excuse (valid reason), a glucose drip should not be administered in the state of fasting, because this is against the wisdom of fasting. (Kitab-un-Nawazil/Vol:6/Page:368)