Terazosin
Terazosin (Hytrin)
Terazosin
(ter-AY-zoh-sin)
Pregnancy Category: C Hytrin (Rx)

Classification: Antihypertensive, alpha-1-adrenergic receptor blocking agent

Action/Kinetics: Blocks postsynaptic alpha-1-adrenergic receptors, leading to a dilation of both arterioles and veins, and ultimately, a reduction in BP. Both standing and supine BPs are lowered with no reflex tachycardia. Also relaxes smooth muscle of the prostate and bladder neck. Usefulness in BPH is due to alpha-1 receptor blockade, which relaxes the smooth muscle of the prostate and bladder neck and relieves pressure on the urethra. Bioavailability is not affected by food. Onset: 15 min. Peak plasma levels: 1-2 hr. t1/2: 9-12 hr. Duration: 24 hr. Excreted unchanged and as inactive metabolites in both the urine and feces.

Uses: Alone or in combination with diuretics or beta-adrenergic blocking agents to treat hypertension. Treat symptoms of benign prostatic hyperplasia.

Special Concerns: Use with caution during lactation. Safety and efficacy have not been determined in children. Geriatric clients may be more sensitive to the hypotensive and hypothermic effects of terazosin.

Side Effects: First-dose effect: Marked postural hypotension and syncope. CV: Palpitations, tachycardia, postural hypotension, syncope, arrhythmias chest pain, vasodilation. CNS: Dizziness, headache, somnolence, drowsiness, nervousness, paresthesia, depression, anxiety, insomnia, vertigo. Respiratory: Nasal congestion, dyspnea, sinusitis, epistaxis, bronchitis, bronchospasm cold or flu symptoms, increased cough, pharyngitis, rhinitis. GI: Nausea, constipation, diarrhea, dyspepsia, dry mouth, vomiting, flatulence, abdominal discomfort or pain. Musculoskeletal: Asthenia, arthritis, arthralgia, myalgia, joint disorders, back pain, pain in extremities, neck and shoulder pain, muscle cramps. Miscellaneous: Peripheral edema, weight gain, blurred vision, impotence, chest pain, fever, gout, pruritus, rash, sweating, urinary frequency, UTI, tinnitus, conjunctivitis, abnormal vision, edema, facial edema.

Laboratory Test Alterations: H&H;, WBCs, albumin.

Overdose Management: Symptoms: Hypotension, drowsiness, shock. Treatment: Restore BP and HR. Client should be kept supine; vasopressors may be indicated. Volume expanders can be used to treat shock.

Drug Interactions: When used with finasteride finasteride plasma levels.

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

Dosage
•Capsules Hypertension.
Individualized, initial: 1 mg at bedtime (this dose is not to be exceeded); then, increase dose slowly to obtain desired response. Range: 1-5 mg/day; doses as high as 20 mg may be required in some clients. Doses greater than 20 mg daily do not provide further BP control.
Benign prostatic hyperplasia.
Initial: 1 mg/day; dose should be increased to 2 mg, 5 mg, and then 10 mg once daily to improve symptoms and/or urinary flow rates. Doses greater than 20 mg daily have not been studied.