This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.
INDICATIONS AND USAGE Prazosin hydrochloride capsules are indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes, including this drug. Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than one drug to achieve blood pressure goals. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program's Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC). Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concl...
CONTRAINDICATIONS Prazosin hydrochloride capsules are contraindicated in patients with known sensitivity to quinazolines, prazosin, or any of the inert ingredients.
WARNINGS As with all alpha-blockers, prazosin hydrochloride capsules may cause syncope with sudden loss of consciousness. In most cases, this is believed to be due to an excessive postural hypotensive effect, although occasionally the syncopal episode has been preceded by a bout of severe tachycardia with heart rates of 120–160 beats per minute. Syncopal episodes have usually occurred within 30 to 90 minutes of the initial dose of the drug; occasionally, they have been reported in association with rapid dosage increases or the introduction of another antihypertensive drug into the regimen of a patient taking high doses of prazosin hydrochloride capsules. The incidence of syncopal episodes is approximately 1% in patients given an initial dose of 2 mg or greater. Clinical trials conducted during the investigational phase of this drug suggest that syncopal episodes can be minimized by limiting the initial dose of the drug to 1 mg, by subsequently increasing the dosage slowly, and by introducing any additional antihypertensive drugs into the patient's regimen with caution (see DOSAGE AND ADMINISTRATION ). Hypotension may develop in patients given prazosin hydrochloride capsules who are...
ADVERSE REACTIONS Clinical trials were conducted on more than 900 patients. During these trials and subsequent marketing experience, the most frequent reactions associated with prazosin hydrochloride therapy are: dizziness 10.3%, headache 7.8%, drowsiness 7.6%, lack of energy 6.9%, weakness 6.5%, palpitations 5.3%, and nausea 4.9%. In most instances, side effects have disappeared with continued therapy or have been tolerated with no decrease in dose of drug. Less frequent adverse reactions which are reported to occur in 1–4% of patients are: Gastrointestinal: vomiting, diarrhea, constipation. Cardiovascular: edema, orthostatic hypotension, dyspnea, syncope. Central Nervous System: vertigo, depression, nervousness. Dermatologic: rash. Genitourinary: urinary frequency. EENT: blurred vision, reddened sclera, epistaxis, dry mouth, nasal congestion. In addition, fewer than 1% of patients have reported the following (in some instances, exact causal relationships have not been established): Gastrointestinal: abdominal discomfort and/or pain, liver function abnormalities, pancreatitis. Cardiovascular: tachycardia. Central Nervous System: paresthesia, hallucinations. Dermatologic: pruritus,...
Source: FDA SPL label for Prazosin Hydrochloride (Prasco Laboratories), effective 20260306. Full label on DailyMed.
These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.
| 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|---|---|---|
| 805 | 747 | 627 | 721 | 685 | 706 | 810 | 365 |
1,447 reports blaming this drug for every million Medicare prescriptions filled, which is 0.5× the typical drug on this site. (1,863 reports in 2024–2026, against 1,287,778 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)
Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.
| Date | Class | Firm | Reason |
|---|---|---|---|
| 03/2026 | Class II | Appco Pharma LLC | cGMP deviation: detection of Nitrosamine Drug Substance-Related Impurities, N-nitroso-prazosin impurity C (NNP) above acceptable limits. |
| 03/2026 | Class II | Appco Pharma LLC | cGMP deviation: detection of Nitrosamine Drug Substance-Related Impurities, N-nitroso-prazosin impurity C (NNP) above acceptable limits. |
| 03/2026 | Class II | Appco Pharma LLC | cGMP deviation: detection of Nitrosamine Drug Substance-Related Impurities, N-nitroso-prazosin impurity C (NNP) above acceptable limits. |
| 10/2025 | Class II | Amerisource Health Services LLC | Failed Impurities/Degradation Specification: presence of N-nitroso Prazosin impurity C above the Carcinogenic Potency Categorization Approach (CPCA) acceptable intake limit |
| 10/2025 | Class II | Amerisource Health Services LLC | Failed Impurities/Degradation Specification: presence of N-nitroso Prazosin impurity C above the Carcinogenic Potency Categorization Approach (CPCA) acceptable intake limit |
| 10/2025 | Class II | Amerisource Health Services LLC | Failed Impurities/Degradation Specification: presence of N-nitroso Prazosin impurity C above the Carcinogenic Potency Categorization Approach (CPCA) acceptable intake limit |
| 04/2022 | Class II | Mckesson Medical-Surgical Inc. Corporate Office | cGMP deviations: Temperature abuse |
Class I = reasonable probability of serious harm. Class II = temporary or reversible harm. Class III = unlikely to harm. Most generic recalls are manufacturing or labeling defects for one lot, not a verdict on the molecule.
Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.
In 2024, drug companies reported $0 in payments to US physicians and hospitals tied to this drug across 0 transactions.
No pending federal MDL names this drug or its brands.
Not named in any federal pharmaceutical settlement of $100M or more on record.
Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.
Same ATC pharmacological class, graded ones first, best grade at the top. Being in the same class does not make them interchangeable for your condition; it makes them worth asking about.