No

Alpha₁ Blockers

Management of mild to moderate hypertension; alone or in combination with other agents such as diuretics or beta-blockers; benign prostate hypertrophy

C

Hypersensitivity to quinazolines (doxazosin, prazosin, terazosin) or any component

Can cause significant orthostatic hypotension and syncope, especially with first dose. Prostate cancer should be ruled out before starting for BPH. Anticipate a similar effect if therapy is interrupted for a few days, if dosage is rapidly increased, or if another antihypertensive drug is introduced.

Asthenia, postural hypotension, dizziness, somnolence, nasal congestion/rhinitis, and impotence were the only events noted in clinical trials to occur at a frequency significantly greater than placebo (p<0.05).

1% to 10%:

Cardiovascular: Edema, palpitations, chest pain, peripheral edema (3%), orthostatic hypotension (2.7% to 3.9%), tachycardia

Central nervous system: Fatigue, nervousness, drowsiness

Gastrointestinal: Dry mouth

Genitourinary: Urinary incontinence

Ocular: Blurred vision

Respiratory: Dyspnea, nasal congestion

<1% (Limited to important or life-threatening symptoms): Sexual dysfunction, priapism, syncope (0.8%)

Symptoms of overdose include hypotension, drowsiness, shock (but very unusual)

Hypotension usually responds to I.V. fluids or Trendelenburg positioning; if unresponsive to these measures, the use of a parenteral vasoconstrictor may be required; treatment is primarily supportive and symptomatic

NSAIDs may reduce antihypertensive efficacy.

ACE inhibitors: Hypotensive effect may be increased.

Beta-blockers: Hypotensive effect may be increased.

Calcium channel blockers: Hypotensive effect may be increased.

Alpha₁-specific blocking agent with minimal alpha₂ effects; this allows peripheral postsynaptic blockade, with the resultant decrease in arterial tone, while preserving the negative feedback loop which is mediated by the peripheral presynaptic alpha₂-receptors; terazosin relaxes the smooth muscle of the bladder neck, thus reducing bladder outlet obstruction

Onset of effect: 1-2 hours

Absorption: Oral: Rapid

Protein binding: 90% to 95%

Metabolism: Extensively in the liver

Half-life: 9.2-12 hours

Time to peak serum concentration: Within 1 hour

Elimination: Principally in feces (60%) and in urine (40%)

Adults: Oral:

Dosage reduction may be needed when adding a diuretic or other antihypertensive agent; if drug is discontinued for greater than several days, consider beginning with initial dose and retitrate as needed; dosage may be given on a twice daily regimen if response is diminished at 24 hours and hypotensive is observed at 2-4 hours following a dose

Benign prostatic hypertrophy: Initial: 1 mg at bedtime, increasing as needed; most patients require 10 mg day; if no response after 4-6 weeks of 10 mg/day, may increase to 20 mg/day

May be administered without regard to meals at the same time each day

Standing and sitting/supine blood pressure, especially following the initial dose at 2-4 hours following the dose and thereafter at the trough point to ensure adequate control throughout the dosing interval; urinary symptoms

Terazosin can be used alone or in combination as an antihypertensive. Patients with BPH may derive an extra benefit from therapy.

Dizziness is common; may cause drowsiness or nervousness; may rarely cause insomnia or depression

None reported

No information available to require special precautions

Up to 10% of patients could experience dry mouth

Take as directed, at bedtime. Do not skip dose or discontinue without consulting prescriber. Follow recommended diet and exercise program. Do not use alcohol or OTC medications which may affect blood pressure (eg, cough or cold remedies, diet pills, "stay-awake" medications) without consulting physician. You may experience drowsiness, dizziness, or impaired judgment (use caution when driving or engaging in tasks that require alertness until response to drug is known); postural hypotension (use caution when rising from sitting or lying position or when climbing stairs); dry mouth or nausea (frequent mouth care or sucking lozenges may help); urinary incontinence (void before taking medication); or sexual dysfunction (reversible, may resolve with continued use). Report altered CNS status (eg, fatigue, lethargy, confusion, nervousness); sudden weight gain (weigh yourself in the same clothes at the same time of day once a week); unusual or persistent swelling of ankles, feet, or extremities; palpitations or rapid heartbeat; difficulty breathing; muscle weakness; or other persistent side effects. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant. Consult prescriber if breast-feeding.

Syncope may occur usually within 90 minutes of the initial dose; administer initial dose at bedtime

Monitor blood pressure, standing and sitting/supine

Capsule: 1 mg, 2 mg, 5 mg, 10 mg

Tablet: 1 mg, 2 mg, 5 mg, 10 mg

Alver JE, Mooppan UM, Kester RR, et al, "The Effects of the Alpha 1-Adrenergic Antagonists Terazosin and Phentolamine on Prostastatic Adenoma and Urethra In Vitro," Proc West Pharmacol Soc, 1989, 32:317-25.

Appell RA, "Pathogenesis and Medical Management of Benign Prostatic Hyperplasia," Semin Nephrol, 1994, 14(6):531-43.

Kim J, Gazarian M, Verjee Z, et al, "Acute Renal Insufficiency in Ibuprofen Overdose," Pediatr Emerg Care, 1995, 11(2):107-8.

Lowe FC, "Safety Assessment of Terazosin in the Treatment of Patients With Symptomatic Benign Prostatic Hyperplasia: A Combined Analysis," Urology, 1994, 44(1):46-51.

Luther RR, "Terazosin: A New Antihypertensive Agent With Favorable Effects on Lipids," Int J Clin Pharmacol Ther Toxicol, 1989, 27(7):313-9.

Petrovich Z, Ameye F, Baert L, et al, "New Trends in the Treatment of Benign Prostatic Hyperplasia and Carcinoma of the Prostate," Am J Clin Oncol, 1993, 16(3):187-200.

Sonders RC, "Pharmacokinetics of Terazosin," Am J Med, 1986, 80(Suppl 5B):20-4.

Titmarsh S and Monk JP, "Terazosin: A Review of Its Pharmacodynamic and Pharmacokinetic Properties, and Therapeutic Efficacy in Essential Hypertension," Drugs, 1987, 33(5):461-77.