The ruling on using sublingual tablets for a person who is fasting

The questioner : The questioner says: Honorable Shaykh, a person suffering from a heart condition has been prescribed by his doctor tablets to place under his tongue when he feels pain. He does not swallow them, and he does not taste them in his throat. Does he break his fast if he uses them during the day of Ramadan when he feels pain?

The Shaykh : We must explain whether these tablets dissolve or not. If they dissolve, they must mix with the saliva, and in that case, he breaks his fast. However, if they do not dissolve, or if they dissolve but he does not swallow his saliva, there is no harm. That is, if they dissolve but he does not swallow them, there is no harm. Just as we rinse our mouths now, and the water has a taste, yet this does not invalidate the fast, because the mouth is considered part of the interior or the exterior? The exterior, yes? It has the ruling of the exterior. For this reason, it is obligatory to purify it in wudu' and it is obligatory to purify it in ghusl.
The important point is that if these tablets dissolve and he swallows the saliva in which they dissolved, his fast is invalidated and he is required to make up the fast. If they do not dissolve, or if they dissolve but he does not swallow the saliva, they do not harm him, just as a woman tastes the food or a person tastes the water when rinsing his mouth, or something similar to that.