The Glorified Allah strictly forbids intoxicants in the Qur’an Al-Karim :
“Oh you who believe! Intoxicants, gambling, idols, arrows for seeking the future or luck are all abominations, the works of the strayed. So, keep away from them that you may attain the true success.”
(Al-Ma’ida/ The Feast 5:90)
If a Muslim person drinks spirits knowing and accepting that it is forbidden (haraam), that person becomes a sinner. However, this situation does not prevent him/her from performing worships. The Glorified Allah sets the following criterion about this issue:
“O you who believe! Do not approach the prayer (salat) when you are in a drunken state until you know what you are saying…” (An-Nisa/ The Women 4:43)
According to this, a Muslim who drinks should not be inebriated to be able to perform the prayers (salat); should be able to stand and be aware of the words he/she speaks. Whoever takes alcoholic drinks cannot do prayers until fulfillment of these conditions.
Anyone who quits drinking and repents, should not wait for forty days, on the contrary should start performing prayers as soon as possible.