Prazosin

Absorption

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 .

Toxicity

TDLO, LD50: Oral TDLO (human): 285 μg/kg; Oral TDLO (woman): 10 μg/kg .
Oral LD50 (rat): 1950 mg/kg; Intraperitoneal LD50 (rat): 102 mg/kg .
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 .

The Uses of Prazosin

Prazosin is used for treating mid-to-moderate hypertension. When using this drug, blood pressure is reduced without any significant change in indicators of cardiac function such as frequency, coronary flow, or cardiac output.

What are the applications of Application

Prazosin is a useful α1 and α2B-adrenoceptor antagonist

Background

Prazosin is a drug used to treat hypertension. Prazosin is marketed by Pfizer and was initially approved by the FDA in 1988. It belongs to the class of drugs known as alpha-1 antagonists.
Recently, many studies have evaluated the benefits of this drug in controlling the symptoms of post-traumatic stress disorder (PTSD) and associated nightmares.

Indications

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).

Pharmacokinetics

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 .

Metabolism

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 .