Note: If therapy is discontinued for several days or more, consider beginning with initial dose and retitrate as needed, due to risk of orthostatic hypotension.
Benign prostatic hyperplasia (monotherapy or combination therapy):
Note : In patients with moderate to severe predominant storage lower urinary tract symptoms, use in combination with beta-3 agonist or anticholinergic agent. In patients with a significantly enlarged prostate (prostate volume >30 mL, prostate-specific antigen >1.5 ng/dL, or palpable prostate enlargement on digital rectal exam), use in combination with 5-alpha reductase inhibitor (AUA [Lerner 2021]).
Oral: Initial: 1 mg once daily at bedtime; titrate slowly every few weeks (eg, to 2 mg, then 5 mg, then 10 mg) based on response and tolerability; usual dose: 10 mg once daily; if no response after 4 to 6 weeks of 10 mg once daily, may increase to a maximum dose of 20 mg once daily.
Hypertension (alternative agent):
Note: Not recommended for initial management, but may be considered as additional therapy for resistant hypertension in patients who do not respond adequately to combination therapy with preferred agents (ACC/AHA [Whelton 2018]).
Oral: Initial: 1 mg once daily; titrate gradually, as needed, based on response and tolerability up to 20 mg/day in 1 or 2 divided doses (ACC/AHA [Whelton 2018]). Note: Administration at bedtime may help limit orthostasis.
Ureteral stone(s) expulsion (off-label use):
Note: Consider for use in patients with ureteral stones >5 and ≤10 mm (Campschroer 2018; Hollingsworth 2016). Although most evidence exists for distal ureteral stones, given the low side effect profile of alpha-blockers, may consider use in patients with stones in any location of ureter (AUA/ES [Assimos 2016a]). Additionally, may consider for use after shock wave lithotripsy to help pass stone fragments (AUA/ES [Assimos 2016a]; Oestreich 2020). A uroselective alpha blocker (eg, tamsulosin) may be preferred to decrease risk of hypotension (Koski 2018).
Oral: 2 to 5 mg once daily at bedtime until stone passage or for up to 4 weeks (Campschroer 2018; Gurbuz 2011; Wang 2009).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
No dosage adjustment necessary.
Hemodialysis: 10% dialyzable; supplemental dose not necessary.
There are no dosage adjustments provided in the manufacturer’s labeling.
(For additional information see "Terazosin: Pediatric drug information")
Hypertension:
Note: Current pediatric blood pressure guidelines do not include terazosin for the management of pediatric hypertension; other agents are preferred (AAP [Flynn 2017]).
Children and Adolescents: Limited data available: Oral: Initial: 1 mg once daily typically administered at bedtime; slowly increase dose to achieve desired blood pressure as tolerated; maximum daily dose: 20 mg/day (NHBPEP 2004; NHLBI 2011). Note: If drug is discontinued for longer than several days, consider beginning with initial dose and retitrate as needed due to risk of postural hypotension and syncope.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Altered kidney function: There are no pediatric-specific dosage recommendations. Based on experience in adult patients, no dosage adjustment is likely necessary.
Hemodialysis: Based on adult information, 10% dialyzable; supplemental dose not necessary.
There are no dosage adjustments provided in the manufacturer’s labeling.
Avoid use for hypertension treatment (Beers Criteria [AGS 2019]). Refer to adult dosing for other indications.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral:
Generic: 1 mg, 2 mg, 5 mg, 10 mg
Yes
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Generic: 1 mg, 2 mg, 5 mg, 10 mg
Oral: Administer at the same time each day.
Oral: Administer without regard to meals at the same time each day.
Benign prostatic hyperplasia: Treatment of symptomatic benign prostatic hyperplasia (BPH).
Hypertension: Management of hypertension. Note: Alpha blockers are not recommended as first line therapy (ACC/AHA [Whelton 2018]).
Ureteral stone(s), expulsion
Beers Criteria: Terazosin is identified in the Beers Criteria as a potentially inappropriate medication in patients 65 years and older due to its high risk of orthostatic hypotension. Avoid use for hypertension treatment (alternative agents have superior risk:benefit profiles) (Beers Criteria [AGS 2019]).
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Adverse reactions reported in adults.
>10%: Nervous system: Asthenia (≤11%), dizziness (9% to 19%), fatigue (≤11%), lassitude (≤11%)
1% to 10%:
Cardiovascular: Orthostatic hypotension (1% to 5%), palpitations (4%), peripheral edema (6%), tachycardia (2%)
Gastrointestinal: Nausea (2% to 4%)
Genitourinary: Impotence (2%)
Nervous system: Drowsiness (4% to 5%), paresthesia (3%), vertigo (1%)
Neuromuscular & skeletal: Back pain (2%), limb pain (4%)
Ophthalmic: Amblyopia (≤1%), blurred vision (≤2%)
Respiratory: Dyspnea (2% to 3%), nasal congestion (≤6%), rhinitis (≤2%), sinusitis (3%)
<1%:
Cardiovascular: Syncope
Endocrine & metabolic: Weight gain
Frequency not defined:
Nervous system: Headache
Miscellaneous: Fever
Postmarketing:
Cardiovascular: Atrial fibrillation
Dermatologic: Acute generalized exanthematous pustulosis (Speck 2008), lichenoid eruption (Koh 2008)
Genitourinary: Priapism
Hematologic & oncologic: Thrombocytopenia
Hypersensitivity: Anaphylaxis, hypersensitivity reaction
Ophthalmic: Intraoperative floppy iris syndrome (Venkatesh 2007)
Hypersensitivity to terazosin or any component of the formulation
Concerns related to adverse effects:
• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery or driving).
• Floppy iris syndrome: Intraoperative floppy iris syndrome has been observed in cataract surgery patients who were on or were previously treated with alpha1-blockers; there appears to be no benefit in discontinuing alpha-blocker therapy prior to surgery. May require modifications to surgical technique.
• Orthostatic hypotension/syncope: May cause significant orthostatic hypotension and syncope, especially with first dose or first few days of therapy; anticipate a similar effect if therapy is interrupted for a few days, if dosage is rapidly increased, or if another antihypertensive drug (particularly vasodilators) or a PDE-5 inhibitor is introduced.
• Priapism: Priapism has been associated with use (rarely); seek immediate medical assistance for erections lasting longer than 4 hours.
Disease-related concerns:
• Heart failure: In a scientific statement from the American Heart Association, terazosin has been determined to be an agent that may exacerbate underlying myocardial dysfunction (magnitude: moderate) (AHA [Page 2016]).
Other warning/precautions:
• Appropriate use: BPH: Rule out prostatic carcinoma before beginning therapy (many symptoms of BPH and prostate cancer are similar).
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the Lexicomp drug interactions program by clicking on the “Launch drug interactions program” link above.
Alpha-/Beta-Agonists: Alpha1-Blockers may diminish the vasoconstricting effect of Alpha-/Beta-Agonists. Similarly, Alpha-/Beta-Agonists may antagonize Alpha1-Blocker vasodilation. Risk C: Monitor therapy
Alpha1-Agonists: Alpha1-Blockers may diminish the vasoconstricting effect of Alpha1-Agonists. Similarly, Alpha1-Agonists may antagonize Alpha1-Blocker vasodilation. Risk C: Monitor therapy
Alpha1-Blockers: May enhance the antihypertensive effect of other Alpha1-Blockers. Risk X: Avoid combination
Amifostine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Amifostine. Management: When used at chemotherapy doses, hold blood pressure lowering medications for 24 hours before amifostine administration. If blood pressure lowering therapy cannot be held, do not administer amifostine. Use caution with radiotherapy doses of amifostine. Risk D: Consider therapy modification
Amphetamines: May diminish the antihypertensive effect of Antihypertensive Agents. Risk C: Monitor therapy
Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may enhance the hypotensive effect of Antipsychotic Agents (Second Generation [Atypical]). Risk C: Monitor therapy
Barbiturates: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Benperidol: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Beta-Blockers: May enhance the orthostatic hypotensive effect of Alpha1-Blockers. The risk associated with ophthalmic products is probably less than systemic products. Risk C: Monitor therapy
Brigatinib: May diminish the antihypertensive effect of Antihypertensive Agents. Brigatinib may enhance the bradycardic effect of Antihypertensive Agents. Risk C: Monitor therapy
Brimonidine (Topical): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Bromperidol: May diminish the hypotensive effect of Blood Pressure Lowering Agents. Blood Pressure Lowering Agents may enhance the hypotensive effect of Bromperidol. Risk X: Avoid combination
Calcium Channel Blockers: Alpha1-Blockers may enhance the hypotensive effect of Calcium Channel Blockers. Risk C: Monitor therapy
Dapoxetine: May enhance the orthostatic hypotensive effect of Alpha1-Blockers. Risk C: Monitor therapy
Dexmethylphenidate: May diminish the therapeutic effect of Antihypertensive Agents. Risk C: Monitor therapy
Diazoxide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
DULoxetine: Blood Pressure Lowering Agents may enhance the hypotensive effect of DULoxetine. Risk C: Monitor therapy
Flunarizine: May enhance the therapeutic effect of Antihypertensive Agents. Risk C: Monitor therapy
Herbal Products with Blood Pressure Increasing Effects: May diminish the antihypertensive effect of Antihypertensive Agents. Risk C: Monitor therapy
Herbal Products with Blood Pressure Lowering Effects: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Hypotension-Associated Agents: Blood Pressure Lowering Agents may enhance the hypotensive effect of Hypotension-Associated Agents. Risk C: Monitor therapy
Levodopa-Containing Products: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa-Containing Products. Risk C: Monitor therapy
Loop Diuretics: May enhance the hypotensive effect of Antihypertensive Agents. Risk C: Monitor therapy
Lormetazepam: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Methylphenidate: May diminish the antihypertensive effect of Antihypertensive Agents. Risk C: Monitor therapy
Molsidomine: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Nicorandil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Nitroprusside: Blood Pressure Lowering Agents may enhance the hypotensive effect of Nitroprusside. Risk C: Monitor therapy
Obinutuzumab: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Management: Consider temporarily withholding blood pressure lowering medications beginning 12 hours prior to obinutuzumab infusion and continuing until 1 hour after the end of the infusion. Risk D: Consider therapy modification
Pentoxifylline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Pholcodine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Pholcodine. Risk C: Monitor therapy
Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Alpha1-Blockers (Nonselective). Management: Ensure patient is stable on one agent prior to initiating the other, and always initiate combination using the lowest possible dose of the drug being added. When tadalafil is used for treatment of BPH, concurrent alpha 1-blockers are not recommended. Risk D: Consider therapy modification
Prostacyclin Analogues: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Quinagolide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Rilmenidine: Alpha1-Blockers may enhance the hypotensive effect of Rilmenidine. Risk C: Monitor therapy
Adverse events have been observed in some animal reproduction studies.
Chronic maternal hypertension may increase the risk of birth defects, low birth weight, preterm delivery, stillbirth, and neonatal death. Actual fetal/neonatal risks may be related to duration and severity of maternal hypertension. Untreated hypertension may also increase the risks of adverse maternal outcomes, including gestational diabetes, myocardial infarction, preeclampsia, stroke, and delivery complications (ACOG 203 2019).
Agents other than terazosin are more commonly used to treat hypertension in pregnancy (ACOG 203 2019; ESC [Regitz-Zagrosek 2018]). Females with preexisting hypertension may continue their medication during pregnancy unless contraindications exist (ESC [Regitz-Zagrosek 2018]).
It is not known if terazosin is present in breast milk.
The manufacturer recommends that caution be exercised when administering terazosin to breastfeeding women.
Standing and sitting/supine BP, especially following the initial dose at 2 to 4 hours following the dose and thereafter at the trough point to ensure adequate control throughout the dosing interval.
Benign prostatic hyperplasia: International Prostate Symptom Score (baseline and 4 to 12 weeks after treatment initiation); urinalysis (baseline); objective and subjective signs of relief of benign prostatic hyperplasia and lower urinary tract symptoms (AUA [Lerner 2021]).
Hypertension: The 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults (ACC/AHA [Whelton 2018]):
Confirmed hypertension and known CVD or 10-year ASCVD risk ≥10%: Target blood pressure <130/80 mm Hg is recommended.
Confirmed hypertension without markers of increased ASCVD risk: Target blood pressure <130/80 mm Hg may be reasonable.
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 action: Antihypertensive effect: 15 minutes; Peak effect: Antihypertensive effect: 2 to 3 hours
Duration of action: Antihypertensive effect: 24 hours
Absorption: Rapid and complete
Protein binding: 90% to 94%
Metabolism: Hepatic; minimal first-pass
Half-life elimination: ~12 hours
Time to peak, plasma: ~1 hour; delayed ~40 minutes with food
Excretion: Feces (~60%, ~20% as unchanged drug); urine (~40%, ~10% as unchanged drug)
Older adult: Plasma clearance was decreased by 31.7% and half-life was 14 hours in patients ≥70 years.
Capsules (Terazosin HCl Oral)
1 mg (per each): $1.61
2 mg (per each): $1.61
5 mg (per each): $1.61
10 mg (per each): $1.61
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