PlainMeds provides educational information only. This is not medical advice. Always consult your doctor or pharmacist.

allopurinol vs prazosin

Side-by-side comparison of allopurinol and prazosin. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

minor Known Drug Interaction

Drug Interactions Prazosin hydrochloride has been administered without any adverse drug interaction in limited clinical experience to date with the following: (1) cardiac glycosides– digitalis and digoxin; (2) hypoglycemics–insulin, chlorpropamide, phenformin, tolazamide, and tolbutamide; (3) tranquilizers and sedatives–chlordiazepoxide, diazepam, and phenobarbital; (4) antigout– allopurinol, colchicine, and probenecid; (5) antiarrhythmics–procainamide, propranolol ( see WARNINGS however), and quinidine; and (6) analgesics, antipyretics and anti-inflammatories– propoxyphene, aspirin,...

Recommendation: You can continue to take both of these medicines as prescribed by your doctor.

Drug Class
allopurinol Xanthine Oxidase Inhibitor
prazosin Alpha-1 Blocker
Type
allopurinol Prescription
prazosin Prescription
Summary
allopurinol

Allopurinol is a medicine that lowers uric acid levels in your body. It helps prevent gout attacks and other problems caused by high uric acid.

prazosin

Prazosin (Minipress) is a medicine that lowers your blood pressure. Lowering blood pressure helps prevent strokes and heart attacks.

What It Treats
allopurinol

This medicine is used to manage gout in adults. Gout causes painful attacks, joint damage, and kidney problems. Allopurinol is also used in adults and children with leukemia, lymphoma, and solid tumors who are getting cancer treatment. It helps manage high uric acid caused by the cancer treatment. It can also help adults who get calcium oxalate kidney stones often.

prazosin

Prazosin is used to treat high blood pressure. Lowering your blood pressure reduces your risk of serious heart problems. It can be used alone or with other blood pressure medicines. Managing high blood pressure should include healthy habits like diet and exercise.

How It Works
allopurinol

Allopurinol works by blocking an enzyme called xanthine oxidase. This enzyme helps your body make uric acid. By blocking it, allopurinol reduces the amount of uric acid in your blood and urine.

prazosin

Prazosin belongs to a class of drugs called alpha-1 blockers. It works by relaxing your blood vessels. This makes it easier for blood to flow through your body, which lowers blood pressure.

Common Side Effects
allopurinol
  • Diarrhea
  • Nausea
  • Increased liver enzyme levels
  • Gout attacks
  • Skin rash
prazosin
  • Dizziness
  • Headache
  • Drowsiness
  • Lack of energy
  • Weakness
FAERS Reports
allopurinol
  • Diarrhea 8,423
  • Tiredness 7,965
  • Difficulty breathing 7,659
  • Feeling sick to your stomach 7,061
  • Death 6,664
prazosin
  • Feeling sick to your stomach 361
  • Head pain 265
  • Feeling lightheaded or unsteady 263
  • Feeling worried or nervous 260
  • Feeling tired 257
Serious Warnings
allopurinol

Allopurinol can cause serious skin reactions that can be deadly. Stop taking this medicine and get medical help right away if you get a skin rash or any other signs of an allergic reaction.

prazosin

Prazosin can cause a sudden drop in blood pressure, especially when you first start taking it. This can make you feel dizzy or faint. To avoid this, take your first dose at bedtime. Be careful when standing up quickly.

Pregnancy
allopurinol

Allopurinol may harm your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is not recommended to breastfeed while taking this medicine because it can pass into breast milk.

prazosin

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if prazosin will harm your unborn baby. Talk to your doctor about the risks and benefits of taking prazosin while pregnant or breastfeeding.

Also Compare, Nearby Drugs

Compare allopurinol with

Compare prazosin with

How to Read This allopurinol vs prazosin Comparison

allopurinol is classified in the Xanthine Oxidase Inhibitor drug class, while prazosin sits within the Alpha-1 Blocker class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, allopurinol has 37,772 submissions while prazosin has 1,406. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to there is no evidence that these two medications cause problems when taken together.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between allopurinol and prazosin - always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.