Praise be to Allah.
Using suppositories during the day does not invalidate the fast. Similarly if a fasting person needs an enema, that does not invalidate the fast . There is no evidence to suggest that this is one of the things that breaks the fast, and because that is not food or drink and does not come under the same heading as food and drink.
Shaykh al-Islam Ibn Tayimiyah said in al-Ikhtiyarat p. 193:
Shaykh Ibn ‘Uthaymin said in al-Sharh al-Mumti’ (6/381):
“The most correct view concerning this matter is the view of Shaykh al-Islam Ibn Taymiyah – i.e. that an enema does not invalidate the fast.?
And Allah knows best.