Question: A woman used nose drops during the daytime in Ramadaan because she could not breathe through her nose without it. She used it for a considerable number of days throughout three or four Ramadaans; she does not remember the number exactly. However, she knew that using these drops during the day in Ramadaan breaks the Sawm (Fast) if the drops reach the throat, and at times she felt the bitterness of the drops in her throat. Is her Sawm invalidated? What is required of her regarding observing Sawm or feeding Miskeens (needy people)?
Answer: If a fasting person must use nose drops, there is nothing wrong with this. Their Sawm remains valid unless they find the taste of drops in their throat. In this case, the Sawm is invalidated and one must make up for that day if its Sawm is obligatory... read more here.