Prazosin

Indications

INDICATIONS AND USAGE Prazosin hydrochloride capsules, USP 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).

Dosage and administration (summary)

DOSAGE AND ADMINISTRATION The dose of prazosin hydrochloride capsules should be adjusted according to the patient’s individual blood pressure response. The following is a guide to its administration: Initial Dose 1 mg two or three times a day (see WARNINGS). Maintenance Dose Dosage may be slowly increased to a total daily dose of 20 mg given in divided doses. The therapeutic dosages most commonly employed have ranged from 6 mg to 15 mg daily given in divided doses. Doses higher than 20 mg usually do not increase efficacy, however a few patients may benefit from further increases up to a daily dose of 40 mg given in divided doses.

Contraindications

CONTRAINDICATIONS Prazosin hydrochloride capsules are contraindicated in patients with known sensitivity to quinazolines, prazosin, or any of the inert ingredients.

Warnings and precautions

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 to 160 beats per minute. Syncopal episodes have usually occurred within 30 to 90 minutes of the initial dose of the drug.

Pregnancy

Usage in Pregnancy Prazosin hydrochloride has been shown to be associated with decreased litter size at birth, 1, 4, and 21 days of age in rats when given doses more than 225 times the usual maximum recommended human dose. No evidence of drug-related external, visceral, or skeletal fetal abnormalities were observed.

Storage and supply

HOW SUPPLIED Prazosin hydrochloride capsules, USP are available as follows: 1 mg Hard gelatin capsules, white opaque cap printed with "GPI (over) 1 mg" and white opaque body printed with "084" contains white to off-white blend.

Source: Prazosin Hydrochloride (Prazosin Hydrochloride) — US FDA prescribing information, 2024-05-14, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.