Prazosin adverse reactions

Prazosin
Prazosin®, Minipress® FDA Package Insert
Indications and Usage
Dosage and Administration
Contraindications
Warnings
Precautions
Adverse Reactions
Drug Interactions
Use in Specific Populations
Overdosage
Description
Clinical Pharmacology
Nonclinical Toxicology
How Supplied/Storage and Handling
Patient Counseling Information
Labels and Packages
Clinical Trials on Prazosin
ClinicalTrials.gov

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Abdurahman Khalil, M.D. [2]

Adverse Reactions

Clinical trials were conducted on more than 900 patients. During these trials and subsequent marketing experience, the most frequent reactions associated with MINIPRESS 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, alopecia, lichen planus.

Genitourinary: incontinence, impotence, priapism.

EENT: tinnitus.

Other: diaphoresis, fever, positive ANA titer, arthralgia.

Single reports of pigmentary mottling and serous retinopathy, and a few reports of cataract development or disappearance have been reported. In these instances, the exact causal relationship has not been established because the baseline observations were frequently inadequate.

In more specificslit-lamp and funduscopic studies, which included adequate baseline examinations, no drug-related abnormal ophthalmological findings have been reported.

Literature reports exist associating MINIPRESS therapy with a worsening of pre-existing narcolepsy. A causal relationship is uncertain in these cases.

In post-marketing experience, the following adverse events have been reported:

Autonomic Nervous System: flushing.

Body As A Whole: allergic reaction, asthenia, malaise, pain.

Cardiovascular, General: angina pectoris, hypotension.

Endocrine: gynecomastia.

Heart Rate/Rhythm: bradycardia.

Psychiatric: insomnia.

Skin/Appendages: urticaria.

Vascular (Extracardiac): vasculitis.

Vision: eye pain.

Special Senses: During cataract surgery, a variant of small pupil syndrome known as Intraoperative Floppy Iris Syndrome (IFIS) has been reported in association with alpha-1 blocker therapy (see PRECAUTIONS).