Complete adverse effect profile including incidence rates and management
Important Safety Information
This is not a complete list of all possible side effects. Contact your healthcare provider if you experience any unexpected symptoms. For serious or life-threatening side effects, seek emergency medical attention immediately.
Clinical trials were conducted on more than 900 patients.
During these trials and subsequent marketing experience, the most frequent reactions associated with prazosin hydrochloride capsules 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.
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.
Like all medications, Prazosin Hcl can cause side effects. However, not everyone who takes this medication will experience them. Many side effects are dose-dependent and may improve as your body adjusts to the medication. Others may require dose adjustment or medical attention.
Contact your healthcare provider promptly if you experience:
Seek immediate emergency medical care if you experience signs of: