-cimetidine
-medicines for colds or hay fever
-medicines for overactive bladder
-sildenafil
-tadalafil
-vardenafil

They need to know if you have any of the following conditions:

-kidney or liver disease
-low blood pressure
-an unusual or allergic reaction to doxazosin, other medicines, foods, dyes, or preservatives
-pregnant or trying to get pregnant
-breast-feeding

Visit your doctor or health care professional for regular checks on your progress. Check your blood pressure regularly. Ask your doctor or health care professional what your blood pressure should be and when you should contact him or her.
Drowsiness and dizziness are more likely to occur after the first dose, after an increase in dose, or during hot weather or exercise. These effects can decrease once your body adjusts to this medicine. Do not drive, use machinery, or do anything that needs mental alertness until you know how this drug affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol can make you more drowsy and dizzy. Avoid alcoholic drinks.
Do not treat yourself for coughs, colds, or pain while you are taking this medicine without asking your doctor or health care professional for advice. Some ingredients may increase your blood pressure.
Your mouth may get dry. Chewing sugarless gum or sucking hard candy, and drinking plenty of water may help. Contact your doctor if the problem does not go away or is severe.
For males, contact your doctor or health care professional right away if you have an erection that lasts longer than 4 hours or if it becomes painful. This may be a sign of a serious problem and must be treated right away to prevent permanent damage.

Keep out of the reach of children and pets.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Throw away any unused drug after the expiration date.