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Treatments > Medications Used In MS

Brand Name Chemical Name


prazosin (PRA-zoe-sin)

Primary Usage in MS

Generic Available
Bladder Dysfunction Yes

Prazosin belongs to the general class of medicines called anti-hypertensives, which are used to treat high blood pressure. It is used in MS help promote the flow of urine through the sphincter.

Proper Usage
Take the first dose of this medication at bedtime. Do not take more or less of this medication than has been prescribed for you.

This medication may cause you to feel dizzy, lightheaded, or faint, especially when you get up from a sitting or lying position. While these effects are most likely to occur after the initial dose, they can happen at any time. You can reduce this problem by taking the medication at bedtime, but take special care if you need to get up in the middle of the night.

Dizziness, lightheadedness, or fainting are more likely to occur if you drink alcohol, stand for too long, or become overheated.

Prazosin can cause you to feel drowsy or less alert. Make sure you know how you react to this medication before driving.

Elderly individuals tend to be more sensitive to the effects of prazosin, and are therefore more likely to experience dizziness, lightheadedness, or fainting.

No birth defects have been reported in pregnant woman using prazosin to control high blood pressure. While animal studies using significantly higher doses than those used in humans have not resulted in any birth defects, lower birth weights have been reported.

Prazosin passes into the breast milk in small amounts, but has not been reported to causes problems in nursing infants.

Be sure that your physician knows if you have any other medical problems, particularly angina (chest pain), severe heart disease, kidney disease.

Possible Side Effects
Side effects that typically go away as your body adjusts to the medication and do not require medical attention unless they continue for several weeks or are bothersome: drowsiness; headache; lack of energy*.

Side effects that should be reported to your physician as soon as possible include: dizziness or lightheadedness, especially when getting up from a lying or sitting position; fainting; loss of bladder control*; pounding heartbeat; swelling of feet or lower legs.

*Since it may be difficult to distinguish between certain common symptoms of MS and some side effects of oxybutynin, be sure to consult your healthcare professionals if an abrupt change of this type occurs.

Medication Index

Other Medications Used to Treat Bladder Dysfunction

For Urination Frequency

Read more on bladder dysfunction and learn management strategies to help live comfortably.

Reprinted with permission from Rosalind C. Kalb (ed.), Multiple Sclerosis: The Questions You Have—The Answers You Need (4th ed.). New York: Demos Medical Publishing, 2007.

Last updated September 19, 2007