Prazosin

Also known as: Furazosin

Drug #597

Prazosin is a piperazinyl quinazoline derivative, is a selective competitive a1 receptor blocking similar to the other alpha I -antagonists doxazosin and terazosin, both of which are longer acting than it. Prazosin is given orally for the management of hypertension. It also has been used in the treatment of heart failure; however, due to the development of tolerance, Prazosin is seldom used for this condition today. It was approved by the FDA in 1976.

← Previous drug Next drug →

Primary Characteristics

Prazosin is also known as Furazosin, Prazosin HCI.

It is of Synthetic origin and belongs to Pyridine.

It belongs to Alpha-1 adrenergic antagonist pharmacological group on the basis of mechanism of action and also classified in Antihypertensive Agents pharmacological group.

Molecular Weight: 419.9 · pK_a: 6.5 · Solubility in Water: 1 in 714 · Solubility in Alcohol: 1 in 156 · Non-proprietary name: Prazosin.

Pharmacokinetics

Absorption: Prazosin has an oral bioavailability is 57%, pre-systemic (first-pass) metabolism accounts for 50%.

Distribution: Prazosin has a volume of distribution is 0.59 l/kg. plasma protein binding is 92 %.

Elimination: it is metabolised via Hepatic, plasma half-life is 2.5 - 2.9 hr, renal excretion is < 10 %.

Indications

Prazosin is primarily indicated in conditions like Congestive heart failure, Dissolution of gallstones, Hypertension, Infertility or irregular cycles, Raynaud's phenomenon.

Prazosin is also indicated for secondary conditions like Raynaud`s syndrome.

Contraindications

None recorded.

Dosage

Prazosin's dosage details are as follows:

Dose	Single Dose	Frequency	Route	Instructions
Adult Dosage
0.5 mg	0.5 mg	Every 12h	PO	Gradually increase after 3-7 days.
20 mg	20 mg	Every 24h	PO	Maintenance.
Paediatric Dosage (20kg)
0.125 mg/kg	0.125 mg/kg	Every 12h	Oral	-
Neonatal Dosage (3kg)
0.125 mg/kg	0.125 mg/kg	Every 12h	Oral	-

Drug Interactions

Unknown4 interactions

4 interactions

Major2 interactions

Always consult your physician for the change of dose regimen or an alternative drug of choice that may strictly be required.

Side Effects

Prazosin in overdosage may give rise to further complications which include Dizziness , Loss of consciousness, Palpitation .

Prazosin produces potentially life-threatening effects which include Hypotension. Careful monitoring is needed with proper medical management.

The signs and symptoms that are produced after acute overdosage of Prazosin are Drowsiness, Depression .

Prazosin is known to cause more or less tolerable side effects which are usually transient. These include Dizziness, Orthostatic hypotension.

Warnings / Precautions

To avoid first dose effect i.e. marked postural hypotension and syncope, initial dose of prazocin should be reduced and to be taken at the bedtime.

Interference in Pathology

Prazosin may interfere in the diagnosis of Test for Phaeochromocytoma .

Available Brands

Click on a strength to view available brands.

Single Ingredient

Tabs

1 mg 2 mg

Storage Conditions

Prazosin should be stored Tab.

Drug Classification

1.12.3.5 — Alpha-1 receptor antagonists

Manufacturers

Manufacturers of Prazosin in Pakistan:

Pfizer