Praise be to Allah.
It is not permissible to mix medicines with alcohol, because alcohol must be thrown away. It was narrated that Abu Sa’eed al-Khudri said: We had some wine belonging to an orphan, and when al-Maa’idah was revealed (i.e., the prohibition of khamr or alcohol), I asked the Messenger of Allaah (peace and blessings of Allaah be upon him) about it and I said, “It belongs to the orphan.” He said: “Pour it away.”
Narrated by al-Tirmidhi, 1263; classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.
If the medicine is mixed with alcohol, and the percentage of alcohol is so great that this medicine is intoxicating, then it is khamr and it is haraam to take it.
If the percentage of alcohol is very low and it does not intoxicate, then it is permissible to take it.
It says in Fataawa al-Lajnah al-Daa’imah (22/110):
It is not permissible to mix medicines with intoxicants, but if it is mixed with alcohol, if drinking a lot of it will cause intoxication, it is haraam to handle it and drink it, whether a small amount or a large amount. If drinking a lot of it will not cause intoxication, then it is permissible to handle it and drink it. End quote.
Shaykh Ibn ‘Uthaymeen said:
With regard to some medicines that contain alcohol, if the effect of the alcohol in the medicine can be seen in the form of intoxication, then it is haraam, but if no effect is seen, and the alcohol is only added to it as a preservative, then there is nothing wrong with it, because the alcoholic content does not have any effect. End quote.
Liqaa’aat il-Baab il-Maftoohah, 3/231.