Terazosin

Absorption

Approximately 90%.

Toxicity

In the event of an overdose, patients may experience hypotension. Blood pressure and heart rate should be controlled by having the patient lie down or by treating with volume expanders or if necessary vasopressors. Patients should be monitored for renal function. Because terazosin is highly protein bound, dialysis is unlikely to provide benefit to overdosing patients.
The oral LD50 in mice is 5500mg/kg.

Chemical properties

White to Off-White Crystalline Powder

The Uses of Terazosin

Terazosin is used for the same indications as is prazosin; however, it has the advantage of being able to be used once a day.

The Uses of Terazosin

An a-1-adrenergicblocker related to prazosin

The Uses of Terazosin

An α-1-adrenergicblocker related to prazosin.

Background

Terazosin is a quinazoline derivative alpha-1-selective adrenergic blocking agent indicated for benign prostatic hyperplasia and hypertension. Terazosin blocks adrenaline's action on alpha-1 adrenergic receptors, causing relaxation of smooth muscle in blood vessels and the prostate.

Indications

Terazosin is indicated for use in treating symptomatic benign prostatic hyperplasia and hypertension.

Definition

ChEBI: Terazosin is a member of quinazolines, a member of piperazines, a member of furans and a primary amino compound. It has a role as an antineoplastic agent, an antihypertensive agent and an alpha-adrenergic antagonist.

Pharmacokinetics

Terazosin is a quinazoline derivative alpha-1-selective adrenergic blocker.

Clinical Use

Alpha-adrenoceptor blocker:
Hypertension
Benign prostatic hyperplasia (BPH)

Synthesis

Terazosin, 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-tetrahydrofuroyl)- piperazine (12.2.13), only differs from prazosin in that the furyl radical is replaced with a tetrahydrofuryl radical. It is synthesized in exactly the same manner except using 1-(2-tetrahydrofuroyl)piperazine instead of 1-(2-furoyl)piperazine [48–51].

Drug interactions

Potentially hazardous interactions with other drugs
Anaesthetics: enhanced hypotensive effect.
Antidepressants: enhanced hypotensive effect with MAOIs.
Avanafil, vardenafil, sildenafil and tadalafil: enhanced hypotensive effect - avoid concomitant use.
Beta-blockers: enhanced hypotensive effect; increased risk of first dose hypotensive effect.
Calcium-channel blockers: enhanced hypotensive effect; increased risk of first dose hypotensive effect.
Diuretics: enhanced hypotensive effect; increased risk of first dose hypotensive effect.
Moxisylyte: possibly severe postural hypotension when used in combination.

Metabolism

The majority of terazosin is hepatically metabolized. The metabolites recovered include 6-O-demethyl terazosin, 7-O-methyl terazosin, a piperozine derivative, and a diamine derivative.

Metabolism

Terazosin is metabolised in the liver; one of the metabolites has antihypertensive activity.
Terazosin is excreted in faeces via the bile, and in the urine, as unchanged drug and metabolites.