• Basic Info
• Top Questions
• Clinical Info

What is this medicine?

PHENOXYBENZAMINE (fen ox ee BEN za meen) is used to treat high blood pressure and sweating associated with pheochromocytoma.

This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.

What should I tell my health care provider before I take this medicine?

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

• heart or circulation disease
• kidney disease
• shock
• stroke
• an unusual or allergic reaction to phenoxybenzamine, other medicines, foods, dyes, or preservatives
• pregnant or trying to get pregnant
• breast-feeding

How should I use this medicine?

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. Take your doses at regular intervals. Do not take your medicine more often than directed. Do not stop taking except on the advice of your doctor or health care professional.

Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

• epinephrine
• medicines for colds and breathing difficulties
• medicines for high blood pressure
• medicines used to treat erectile dysfunction (ED) like sildenafil, tadalafil, and vardenafil
• other alpha-blockers like alfuzosin, doxazosin, phentolamine, prazosin, tamsulosin, terazosin
• reserpine

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medicine?

Visit your doctor or health care professional for regular checks on your progress.

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.