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Prazosin HCl and Polythiazide oral

Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.


(PRAY-zoh-sin WITH paw-lee-THIGH-uh-zide)


WARNING: This combination medication is not intended to be the first drug to be tried in controlling high blood pressure. It should only be used after other treatments have been tried and after the ideal dose has been determined (titrated). Your blood pressure medication may need to be adjusted or changed by your doctor as needed.


Prazosin helps to widen arteries and veins so blood flows better. Polythiazide is a diuretic (water pill) that helps rid the body of excess fluid. This combination medication is used to treat hypertension (high blood pressure) and certain types of heart disease.

How To Use

Take this medication exactly as prescribed. Try to take it at the same time each day. Take the first dose at bedtime to minimize the chances of getting dizzy or fainting. Do not stop taking this medication without consulting your doctor. Some conditions may become worse when the drug is abruptly stopped. Your dose may need to be gradually decreased. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick.

Side Effects

Dizziness, headache, diarrhea, constipation, loss of appetite, nausea, loss of taste, flushing, fatigue or increased urination may occur the first several days as your body adjusts to the medication. If these effects continue or become bothersome, inform your doctor. Notify your doctor if you develop: chest pain, difficulty breathing, skin rash, tingling of the hands or feet, yellowing of the skin or eyes. Males - though it is unlikely to occur, if you get a painful, prolonged erection, stop using this drug and seek immediate medical attention. If you notice other effects not listed above, contact your doctor or pharmacist.


Before taking this medication, tell your doctor if you have: heart or blood vessel disease, diabetes, liver or kidney disease, lupus, pancreas trouble, gout. To avoid dizziness or fainting, get up slowly from a lying or seated position; especially when you first start using this drug or if your doctor changes your dosing. Limit your intake of alcohol and avoid getting overheated because they may increase the dizziness and drowsiness effects of this drug. Use caution performing tasks requiring alertness such as driving or using machinery. This medication can increase sensitivity to sunlight. Avoid prolonged sun exposure. Wear protective clothing and use a sunscreen. This medication should be used only when clearly needed during pregnancy. Since the drug appears in breast milk, breast-feeding is not recommended. Consult with your doctor.

Drug Interactions

Tell your doctor of all prescription and nonprescription drugs you may use, especially of: lithium, diazoxide, cholestyramine, colestipol, drugs used to treat diabetes, beta-blockers (e.g., atenolol, propranolol), verapamil. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include drowsiness and lightheadedness.


It is important to have your blood pressure checked regularly while taking this medication. Learn how to take your blood pressure. Discuss this with your doctor or pharmacist.

Missed Dose

If you miss a dose, take as soon as remembered; do not take if it is almost time for the next dose, instead, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.


Store at room temperature away from sunlight and moisture.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).