What is the ruling on someone who broke their fast because they forgot to take essential medication for chronic epilepsy during the fasting period in the daytime in Ramadan, especially since the fasting duration was 19 hours?

There is no sin in taking medicine for fear of illness, but the day that was broken due to this excuse must be made up, as Allah Almighty says: "And whoever is ill or on a journey - then an equal number of other days." Some scholars have permitted acting upon the advice of a trustworthy non-Muslim doctor. Holding back for the rest of the day is a precautionary measure, but the preponderant opinion is that it is not obligatory to hold back.