What is the ruling on inhaling a liquid medicine—an antibiotic and an antihistamine—through the nose using a device that converts it into vapor?

The majority of jurists hold that anything reaching the throat through the nose is considered one of the things that invalidate the fast, whether it be food or medicine. Ibn Qudamah stated that anything entering the body cavity or any hollow part of the body that reaches the stomach invalidates the fast if it reaches it by the choice of the fasting person and is something that can be avoided, whether it enters through the mouth, nose, ear, or eye.

Furthermore, the two Sheikhs, Ibn Baz and Ibn Uthaymeen, affirmed that nasal drops are not permissible for a fasting person if they reach his throat or stomach, citing the Prophet's (peace be upon him) saying to Laqeet ibn Sabirah: "And gargle thoroughly unless you are fasting." And whoever does so and finds its taste in his throat must make up for that day. However, if the nasal drops do not reach the stomach, they do not invalidate the fast.