Prazosin

383.4

383.40

242-885-8

XM03YJ541D

DTXSID4049082

C767

C02CA01|C - Cardiovascular system

2934999090

107

1.3

Solid

1.3275 (rough estimate)

279 °C

510.33°C (rough estimate)

339.9ºC

1.7600 (estimate)

6.93e-01 g/L

3.4E-16mmHg at 25°C

Flammable; burning produces toxic nitrogen oxide fumes

6.54None

6.54

192.7 Ų [M+H]+ [CCS Type: TW, Method: Major Mix IMS/Tof Calibration Kit (Waters)]

Warehouse ventilated, low temperature and dry

Prazosin hydrochloride capsules should be stored in well closed, light resistant containers at 15-30 deg C.

|Warning|H315 (100%): Causes skin irritation [Warning Skin corrosion/irritation]|P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, and P501|The GHS information provided by 1 company from 1 notification to the ECHA C&L Inventory.

**TDLO, LD50**: Oral TDLO (human): 285 μg/kg; Oral TDLO (woman): 10 μg/kg [MSDS]. Oral LD50 (rat): 1950 mg/kg; Intraperitoneal LD50 (rat): 102 mg/kg [MSDS]. **Overdose information** Accidental ingestion of at least 50 mg of prazosin by a two-year-old child led to severe drowsiness with depressed reflexes. There was no fall in blood pressure, and the child recovered without complication. **Use in pregnancy** There are no adequate and well-controlled studies determining the safety of prazosin use during pregnancy. It is considered a pregnancy category C drug. Prazosin should be used during pregnancy only in cases where the benefit outweighs the possible risk to the mother and fetus. In specific cases where blood pressure control was emergent during pregnancy, prazosin has been used and no effects on the fetus or neonate were reported. **Use in nursing** This drug is found excreted in small concentrations in human milk. This drug should be used with caution when used during nursing.

Prazosin has been associated with a low rate of serum aminotransferase elevations that in controlled trials was no higher than with placebo therapy. These elevations were transient and did not require dose modification. No instances of clinically apparent acute liver injury due to prazosin have been published in the literature, but reports of cholestatic hepatitis have been received by the sponsor. Among the alpha adrenergic receptor antagonists, the most frequently implicated agent in causing liver injury has been alfuzosin with only single, and not well documented cases linked to other alpha blockers. Thus, acute symptomatic liver injury due to prazosin is quite rare, and severe hepatotoxicity must be exceeding rare, if it occurs at all.

Highly bound to proteins with 97% binding to albumin and alpha 1-acid glycoprotein. Prazosin is thought to be mostly (about 80-90%) bound to albumin.

This drug is indicated for the treatment of hypertension (high blood pressure). Prazosin can be given alone or given with other blood pressure-lowering drugs, including diuretics or beta-adrenergic blocking agents. Prazosin does not negatively impact lung function, and therefore may be used to manage hypertension in patients who are asthmatic or patients with chronic obstructive lung disease (COPD).|FDA Label

Prazosin is a nonselective alpha-adrenergic antagonist (alpha-blocker) used in the therapy of hypertension. Prazosin is associated with a low rate of transient serum aminotransferase elevations and has not been clearly linked to clinically apparent acute liver injury.

Antihypertensive Agents

**Effects on blood pressure** The pharmacodynamic and therapeutic effect of this drug includes is a decrease in blood pressure as well as clinically significant decreases in cardiac output, heart rate, blood flow to the kidney, and glomerular filtration rate. The decrease in blood pressure may occur in both standing and supine positions. Many of the above effects are due to vasodilation of blood vessels caused by prazosin, resulting in decreased peripheral resistance,. Peripheral resistance refers to the level resistance of the blood vessels to blood that flows through them. As the blood vessels constrict (narrow), the resistance increases and as they dilate (widen), and peripheral resistance decreases, lowering blood pressure. **Effects on sleep disturbance related to post-traumatic stress disorder (PTSD)** Some studies have suggested that this drug improves sleep in patients suffering from insomnia related to nightmares and post-traumatic stress disorder, caused by hyperarousal. This effect likely occurs through the inhibition of adrenergic stimulation found in states of hyperarousal.

Drugs that bind to and block the activation of ADRENERGIC ALPHA-1 RECEPTORS. (See all compounds classified as Adrenergic alpha-1 Receptor Antagonists.)|Drugs used in the treatment of acute or chronic vascular HYPERTENSION regardless of pharmacological mechanism. Among the antihypertensive agents are DIURETICS; (especially DIURETICS, THIAZIDE); ADRENERGIC BETA-ANTAGONISTS; ADRENERGIC ALPHA-ANTAGONISTS; ANGIOTENSIN-CONVERTING ENZYME INHIBITORS; CALCIUM CHANNEL BLOCKERS; GANGLIONIC BLOCKERS; and VASODILATOR AGENTS. (See all compounds classified as Antihypertensive Agents.)

After administration of an oral dose, peak plasma concentrations are attained at approximately 3 hours. There is a linear association between the prazosin dose given and plasma concentration at steady state.|This drug is mainly excreted in the bile and the feces.|About 0.6 L/kg.|In patients with congestive heart failure, the clearance of this drug is decreased. Impairment of renal function does not have relevant effects on elimination.

In animals, prazosin hydrochloride is heavily metabolized. This occurs through liver demethylation and conjugation. Some studies in humans or human cells in vitro show similar prazosin metabolism.

The plasma half-life is about 2-3 hours.

Alpha-adrenergic receptors are essential for the regulation of blood pressure in humans. Two types of alpha receptors, alpha 1 and alpha 2, both play a role in regulating blood pressure. Alpha-1 receptors are postsynaptic (located after the nerve junction, or space between a nerve fiber and target tissue). In this case, the target tissue is the vascular smooth muscle. These receptors, when activated, increase blood pressure. Prazosin inhibits the postsynaptic alpha-1 adrenoceptors. This inhibition blocks the vasoconstricting (narrowing) effect of catecholamines (epinephrine and norepinephrine) on the vessels, leading to peripheral blood vessel dilation. Through blood vessel constriction by adrenergic receptor activation, epinephrine and norepinephrine normally act to increase blood pressure.

Furazosin

Pharmaceuticals