The ruling on Injections during the Daytime of Ramadhan
Question :
Do shots and medical injections during the daytime of Ramadhan have any effect on the fast?
Answer:
Medical injections are of two types. The purpose of one of them is nourishment and to sustain the body without the need of eating and drinking, because it has the same meaning. Therefore, this type breaks the fast, because of the texts of the Islamic law, if the meaning which they contain is present in any form, then this form is given the ruling of that text. In reference to the second type, it is the injection that does not nourish. This means that it is not a substitute for eating and drinking. This type does not break the fast because the text does not relate to it in wording or meaning. For it is not food or drink, nor does it have the meaning of food or drink. The basic principle is that the fast is correct until it is confirmed that something corrupts it according to the evidence of the Islamic law.
Source:
Ash-Shaykh Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 3 Page 268