Names and pronunciation
(ter-ay′zoe-sin)
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Drug reference
(ter-ay′zoe-sin)
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Func. class.: Antihypertensive
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Chem. class.: α-Adrenergic blocker
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ACTION: Decreases total vascular resistance, which is responsible for a decrease in B/P; this occurs by the blockade of α1-adrenoreceptors
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USES: Hypertension, as a single agent or in combination with diuretics or β-blockers; BPH
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CONTRAINDICATIONS: Hyper- sensitivity Precautions: Pregnancy, breastfeeding, children, prostate cancer, syncope
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SIDE EFFECTS CNS: Dizziness, headache, drowsiness, anxiety, depression, vertigo, weakness, fatigue, syncope CV: Palpitations, orthostatic hypotension, tachycardia, edema, rebound hypertension EENT: Blurred vision, epistaxis, tinnitus, dry mouth, red sclera, nasal congestion, sinusitis GI: Nausea, vomiting, diarrhea, constipa- tion, abdominal pain GU: Urinary frequency, incontinence, impotence, priapism RESP: Dyspnea, cough, pharyngitis, nasal congestion
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INTERACTIONS effects—β- Increase: hypotensive blockers, nitroglycerin, verapamil, other antihypertensives, alcohol, phosphodies- terase (PDE5) inhibitors (vardenafil, tadalafil, sildenafil) Decrease: hypotensive effects—estrogens, NSAIDs, sympathomimetics, salicylates Drug/Herb Increase: antihypertensive effect— hawthorn Decrease: antihypertensive effect— ephedra Drug/Lab Test Decrease: HB, WBC, platelets, albumin
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DOSAGE AND ROUTES Hypertension • Adult: PO 1 mg at bedtime, may in- crease dose slowly to desired response; max 20 mg/day divided q12hr Benign prostatic hyperplasia • Adult: PO 1 mg at bedtime, gradually increase up to 5-10 mg; max 20 mg di- vided q12hr
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Available forms: Caps 1, 2, 5, 10 mg
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Administer: • Give dose at bedtime; patient should not operate machinery because fainting may occur • If treatment is interrupted for several days, restart with initial dose • Without regard to food; feeding tube: place cap in 60 mL of warm tap water; stir until liquid spills from rup- tured shell (5 min); stir until cap dis- solves; draw solution into oral syringe; give through feeding tube; flush with water • Store at room temperature
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Assess: • BPH: urinary patterns (hesitancy, fre- quency, change in stream, dribbling, dys- uria, urgency) • Hypertension: crackles, dyspnea, or- thopnea q30min; orthostatic B/P, pulse, jugular venous distention q4hr; weight daily, I&O • First dose effect: hypotension/syncope; orthostatic B/P • Labs: BUN, uric acid if patient receiv- ing long-term therapy • Beers: avoid use in older adults as antihypertensive; high risk of orthostatic hypotension T • Pregnancy/breastfeeding: use only if benefits outweigh fetal risk; cautious use in breastfeeding, excretion unknown
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Evaluate: • Therapeutic response: decreased B/P, edema in feet, legs; decreased symptoms of BPH
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • That fainting occasionally occurs after 1st dose; not to drive or operate machinery for 4 hr after 1st dose or after an increase in dose; to take 1st dose at bedtime • To rise slowly from sitting or lying position • Not to discontinue abruptly; if doses have been missed for several days, notify prescriber; dose may need to be retitrated • Not to drink alcohol • Hypertension: to continue with regi- men, including diet, exercise
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PHARMACOKINETICS Half-life 9-12 hr; protein binding 90%-94%; metabolized in liver; excreted in urine, feces; peak 2-3 hr, onset 15 min, duration 24 hr
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• Adult: PO 1 mg at bedtime, may in- crease dose slowly to desired response; max 20 mg/day divided q12hr Benign prostatic hyperplasia
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• Adult: PO 1 mg at bedtime, gradually increase up to 5-10 mg; max 20 mg di- vided q12hr
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