Your kidneys primary function is to filter harmful substances from your blood, with alcohol being one of those substances. When your body has absorbed large amounts of alcohol, it causes the kidneys less able to filter your blood and making it work harder. High blood pressure is caused by large amounts of alcohol which is one of the most common causes of kidney disease.
Alcohol dehydrates the body which affects the normal function of cells and organs, including the kidneys. When the liver fails from too much alcohol consumption, this creates more work for the kidneys and throwing off the balance between the liver and kidneys which will lead to the kidneys failing as well.