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Terazosin

Editor: Avais Raja Updated: 3/13/2023 3:57:43 PM

Indications

Terazosin was approved by the Food and Drug Administration (FDA) in 1987 initially as a treatment for hypertension.[1] Later in 1993, it was approved as a treatment for lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia.[2] The role of pharmacologic therapy in distal urinary tract stones is currently a focus of research, with terazosin and other alpha-1 antagonists under consideration for potential therapeutic value in addition to its traditionally accepted symptomatic relief effects.[3] 

Off-label uses for terazosin currently being studied include the following:

  • In more recent literature, terazosin, among other agents of its class been the subject of research as an off-label agent for the use of medical expulsive therapy (MET), a form of medical management for distal ureteral calculi.[4][5]
  • Alleviation of nightmares associated with post-traumatic stress disorder (PTSD)[3]
  • Antihidrotic in patients who have hyperhidrosis related to selective serotonin reuptake inhibitor (SSRI) use[6] 
  • Chronic prostatitis/chronic pelvic pain syndrome[7]
  • Urethritis associated with radiation therapy[8]
  • Idiopathic oligozoospermia[9]

Mechanism of Action

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Mechanism of Action

Terazosin is a selective, quinazoline-derived post-synaptic alpha-1 antagonist.[10] Alpha-1 adrenergic receptors subdivide into alpha-1A, alpha-1B, and alpha-1D.[11] Due to their nature as adrenergic receptors, they are members of the G-protein coupled receptor category. Terazosin is a competitive antagonist at these receptors, similar to other selective alpha-1 antagonists such as prazosin and doxazosin, notably at alpha-1A, which comprises the majority of alpha receptors in the urothelium.[12] The alpha-1 receptors are commonly located diffusely in smooth muscle tissue, including vascular smooth muscle, sphincter smooth muscle, and urinary bladder smooth muscle.[13]

Alpha-1 adrenergic receptors are also present in many other organ systems, including the central nervous system, endocrine system, and gastrointestinal system. The primary anti-hypertensive action occurs by blocking vascular smooth muscle in the arterioles. The anti-obstructive urinary tract effects result from smooth muscle relaxation in the ureters, bladder, and urethral sphincter.[14] Terazosin's exertion of an anti-nightmare effect does not have a clearly elucidated mechanism. However, a possible explanation could be due to the presence of presynaptic alpha-adrenergic receptors in the central nervous system.

Administration

Terazosin is available in the US in oral capsule formulation in the form of a hydrochloride salt, available in 1 mg, 2 mg, 5 mg, and 10 mg formulations. For the FDA approved indications of hypertension and benign prostatic hyperplasia, the dosing route, frequency, and amount are as follows:

Hypertension

The initial dose is 1 mg to 10 mg orally daily, titrated upwards as needed to a maximum of 20 mg daily. Considered a second-line agent due to adverse effects, additional consideration as an agent if the patient also experiences lower urinary tract symptoms associated with benign prostatic hyperplasia.[15][16]

Benign Prostatic Hyperplasia

The initial dose is 1 mg to 10 mg orally at bedtime, titrated upwards as needed based upon patient response up to 20 mg daily in 1 or 2 divided doses.[17]

For Non-FDA approved indications, including medical expulsive therapy (MET), chronic prostatitis, hyperlipidemia, urethritis, hyperhidrosis, and oligospermia:

Medical Expulsive Therapy for Distal Ureteral Calculi

2 mg to 10 mg orally at bedtime. Most studies have indicated usage of 2 mg to 5 mg, and only rarely have 10 mg doses been cited. For MET, the typical duration of terazosin is for up to 2 weeks, and the patient may discontinue therapy following the expulsion of the stone.[4]

Chronic Prostatitis/Chronic Pelvic Pain Syndrome

1 mg to 5 mg orally daily for 14 weeks. Terazosin demonstrated effectiveness in a study comparing alpha-antagonist naïve patients with chronic prostatitis/chronic pelvic pain syndrome with a placebo.[7]

Hyperlipidemia/Hypercholesterolemia

5 mg, 10 mg, or 20 mg orally daily. Studies demonstrating the lipid-lowering effects were subject to confounding factors due to titration of drug dosing to diastolic blood pressure or meeting the maximum (20 mg) dosage for terazosin. Additionally, there have not been studies to demonstrate a mortality benefit, as seen for other lipid-lowering drugs.[18][19]

Idiopathic Oligozoospermia

2 mg orally daily. One clinical study by Gregoriou et al. demonstrated a statistically significant improvement in spermatozoa count and seminal fluid volume after treatment with six months of terazosin. However, the study noted no change in the mean percentage of abnormal spermatozoa and also did not detect any significant difference in pregnancy rates.[9]

Urethritis associated with Radiotherapy in Prostate Cancer

2 mg to 6 mg orally daily. One study from Zelefsky et al. suggests an improvement in urinary tract symptoms associated with radiotherapy for localized prostate cancer.[20]

Antidepressant-induced Excessive Sweating

1 mg to 6 mg orally daily. A recent clinical trial demonstrated a positive response to hyperhidrosis associated with selective serotonin reuptake inhibitor use.[3]

Adverse Effects

Terazosin is generally well-tolerated. Many adverse effects of terazosin are explainable due to its blockade of alpha-1 adrenergic receptors.[16][14]

  • Statistically significant adverse effects associated with terazosin detected in placebo-controlled trials listed in the FDA database include dizziness, headache, weakness, postural hypotension, and nasal congestion.[21][22]
  • First-dose syncope is rare and may be mitigated by bedtime use. Orthostatic hypotension is common and should merit strong consideration when prescribing terazosin.[23] 
  • According to the FDA, post-marketing surveys also found priapism, atrial fibrillation, anaphylaxis, and intraoperative floppy iris syndrome associated with terazosin use, though instances of such occurrences were extremely rare.

Drug Interactions

Terazosin has been used in many patients on various concomitant medicines; while these interactions are not studied extensively, no interactions are observed.

Contraindications

The only absolute contraindication to the usage of terazosin is allergy or hypersensitivity to the medication. Relative contraindications include usage in geriatric populations due to the potential for patient harm associated with syncope and/or postural hypotension due to terazosin use, patients with heart failure, and general intolerance of the adverse effects associated with terazosin.[24] It is important to note that in geriatric patient populations, the occurrence of syncope or orthostatic hypotension can lead to falls, which are associated with increased mortality, morbidity, loss of functional capacity, and institutionalization for diagnostic workup/rehabilitation related to the syncope.[25]

While terazosin is not contraindicated for use in pediatric populations, caution is advised due to limited data available regarding the use of the drug in children. However, there are small studies of safe usage in children without adverse outcomes.[26][27]

Warnings

Prostatic Cancer

BPH and prostate carcinoma can cause many similar symptoms, and both diseases usually co-exist. Hence, patients thought to have benign prostatic hyperplasia should be tested before starting terazosin to exclude the carcinoma of the prostate.

Intraoperative Floppy Iris Syndrome (IFIS)

During cataract surgery, IFIS has been observed in some patients treated with alpha-1 blockers presently or in the past. Therefore, the ophthalmologist should consider possible modifications of surgical techniques, such as using iris dilator rings, iris hooks, or viscoelastic substances. There is no benefit of stopping terazosin before cataract surgery.

Monitoring

The use of terazosin does not require plasma/blood drug level monitoring. However, after the first dose, vital orthostatic signs should be obtained to exclude postural hypotension. If used for hypertension, orthostatic blood pressures may be checked regularly during the titration interval to confirm efficacy.[1] If used for lower urinary tract symptoms associated with benign prostatic hyperplasia, standard clinical assessment of patients may determine efficacy.[5]

Toxicity

Overdose of terazosin may lead to hypotension, and standard life-support protocols should be in place for instances of hemodynamic instability. There are no antidotes for terazosin toxicity specifically. Vasopressors may be used to support physiologic blood pressure parameters in the event of terazosin overdose. Terazosin is long-acting, with an elimination half-life of approximately 12 hours, and is highly protein-bound. Elimination is via renal excretion (40%) and via excretion of feces (60%).[28]

Enhancing Healthcare Team Outcomes

Medications are crucial components of the practice of medicine. In addition to procedural treatments, medications represent an essential aspect of therapy delivery. However, the process of delivering medication to a patient involves a complex interplay between interprofessional healthcare team members from several disciplines. 

  • A qualified physician or mid-level practitioner (NP or PA) must prescribe the medication with appropriate knowledge and assessment of the medication's efficacy and safety profiles according to the patient's demographics, comorbidities, and clinical needs. 
  • The pharmacist who receives the prescription must verify that the dosage prescribed is appropriate and is responsible for communicating with the provider should any mistake or unsafe prescription be discovered and check for potential drug-drug interactions. 
  • The pharmacy technician assisting the pharmacist is encouraged to aid in this role and remain vigilant when physically placing the pills in a bottle and ensuring the label is clear and correct. 
  • The nurse is responsible for administrating the medication to the patient requires vigilance and awareness of the potential hypotension associated with Terazosin and should be meticulous in their measurement of vital orthostatic signs after administration.
  • A medical assistant may also assist in measuring vital signs and could be the first person to discover medication safety issues.
  • The patient and/or their caregiver are the crucial final step in the process, verbalizing any questions or concerns they may have regarding the use of the prescribed medication and signs/symptoms for which they should be vigilant.

Though Terazosin is relatively contraindicated in geriatric populations, it may still prove to be a useful drug that treats multiple comorbidities at once to limit polypharmacy.[29] [Level 3] Terazosin is mainly prescribed for patients with hypertension and BPH.[30][31]  The patient and the rest of the healthcare team, including their physician/mid-level, pharmacy team, and the nursing team, should remain vigilant and aware of the possibility of hypotension or arrhythmia associated with terazosin use. With this type of interprofessional team approach, there can be a maximal therapeutic benefit with minimal adverse events. [Level 5]

References


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Itskovitz HD. Alpha 1-blockade for the treatment of hypertension: a megastudy of terazosin in 2214 clinical practice settings. Clinical therapeutics. 1994 May-Jun:16(3):490-504     [PubMed PMID: 7923316]


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Kaplan SA. alpha-Blocker Therapy: Current Update. Reviews in urology. 2005:7 Suppl 8(Suppl 8):S34-42     [PubMed PMID: 16985889]


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Ghaleiha A, Shahidi KM, Afzali S, Matinnia N. Effect of terazosin on sweating in patients with major depressive disorder receiving sertraline: a randomized controlled trial. International journal of psychiatry in clinical practice. 2013 Feb:17(1):44-7. doi: 10.3109/13651501.2012.687449. Epub 2012 Jun 26     [PubMed PMID: 22731399]

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Sridharan K, Sivaramakrishnan G. Efficacy and safety of alpha blockers in medical expulsive therapy for ureteral stones: a mixed treatment network meta-analysis and trial sequential analysis of randomized controlled clinical trials. Expert review of clinical pharmacology. 2018 Mar:11(3):291-307. doi: 10.1080/17512433.2018.1424537. Epub 2018 Jan 19     [PubMed PMID: 29334287]

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Preminger GM, Tiselius HG, Assimos DG, Alken P, Buck C, Gallucci M, Knoll T, Lingeman JE, Nakada SY, Pearle MS, Sarica K, Türk C, Wolf JS Jr, EAU/AUA Nephrolithiasis Guideline Panel. 2007 guideline for the management of ureteral calculi. The Journal of urology. 2007 Dec:178(6):2418-34     [PubMed PMID: 17993340]


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Detweiler MB, Pagadala B, Candelario J, Boyle JS, Detweiler JG, Lutgens BW. Treatment of Post-Traumatic Stress Disorder Nightmares at a Veterans Affairs Medical Center. Journal of clinical medicine. 2016 Dec 16:5(12):. doi: 10.3390/jcm5120117. Epub 2016 Dec 16     [PubMed PMID: 27999253]


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Cheah PY, Liong ML, Yuen KH, Teh CL, Khor T, Yang JR, Yap HW, Krieger JN. Terazosin therapy for chronic prostatitis/chronic pelvic pain syndrome: a randomized, placebo controlled trial. The Journal of urology. 2003 Feb:169(2):592-6     [PubMed PMID: 12544314]

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Zelefsky MJ, Ginor RX, Fuks Z, Leibel SA. Efficacy of selective alpha-1 blocker therapy in the treatment of acute urinary symptoms during radiotherapy for localized prostate cancer. International journal of radiation oncology, biology, physics. 1999 Oct 1:45(3):567-70     [PubMed PMID: 10524407]

Level 2 (mid-level) evidence

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Gregoriou O, Vitoratos N, Papadias C, Gargaropoulos A, Konidaris S, Giannopoulos V, Chryssicopoulos A. Treatment of idiopathic oligozoospermia with an alpha-blocker: a placebo-controlled double-blind trial. International journal of fertility and women's medicine. 1997 Sep-Oct:42(5):301-5     [PubMed PMID: 9406835]

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Piascik MT, Perez DM. Alpha1-adrenergic receptors: new insights and directions. The Journal of pharmacology and experimental therapeutics. 2001 Aug:298(2):403-10     [PubMed PMID: 11454900]

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Taylor BN, Cassagnol M. Alpha Adrenergic Receptors. StatPearls. 2022 Jan:():     [PubMed PMID: 30969652]


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Schmitz JM, Graham RM, Sagalowsky A, Pettinger WA. Renal alpha-1 and alpha-2 adrenergic receptors: biochemical and pharmacological correlations. The Journal of pharmacology and experimental therapeutics. 1981 Nov:219(2):400-6     [PubMed PMID: 6270306]

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[13]

Langer SZ. History and nomenclature of alpha1-adrenoceptors. European urology. 1999:36 Suppl 1():2-6     [PubMed PMID: 10438241]


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Kyncl JJ. Pharmacology of terazosin. The American journal of medicine. 1986 May 23:80(5B):12-9     [PubMed PMID: 2872801]

Level 3 (low-level) evidence

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Whelton PK, Carey RM, Aronow WS, Casey DE Jr, Collins KJ, Dennison Himmelfarb C, DePalma SM, Gidding S, Jamerson KA, Jones DW, MacLaughlin EJ, Muntner P, Ovbiagele B, Smith SC Jr, Spencer CC, Stafford RS, Taler SJ, Thomas RJ, Williams KA Sr, Williamson JD, Wright JT Jr. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension (Dallas, Tex. : 1979). 2018 Jun:71(6):1269-1324. doi: 10.1161/HYP.0000000000000066. Epub 2017 Nov 13     [PubMed PMID: 29133354]

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Titmarsh S, Monk JP. Terazosin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in essential hypertension. Drugs. 1987 May:33(5):461-77     [PubMed PMID: 2885169]

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Paick JS, Ku JH, Shin JW, Yang JH, Kim SW. alpha-blocker monotherapy in the treatment of nocturia in men with lower urinary tract symptoms: a prospective study of response prediction. BJU international. 2006 May:97(5):1017-23     [PubMed PMID: 16643483]


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Deger G. Effect of terazosin on serum lipids. The American journal of medicine. 1986 May 23:80(5B):82-5     [PubMed PMID: 2872813]

Level 1 (high-level) evidence

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López A, Wright JM. Rosuvastatin and the JUPITER trial: critical appraisal of a lifeless planet in the galaxy of primary prevention. International journal of occupational and environmental health. 2012 Jan-Mar:18(1):70-8     [PubMed PMID: 22550699]

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Wilt TJ, Howe RW, Rutks IR, MacDonald R. Terazosin for benign prostatic hyperplasia. The Cochrane database of systematic reviews. 2002:(4):CD003851     [PubMed PMID: 12519611]

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[21]

Oh EY, Bae SK, Kwon JW, You M, Lee DC, Lee MG. Pharmacokinetic and pharmacodynamic consequences of inhibition of terazosin metabolism via CYP3A1 and/or 3A2 by DA-8159, an erectogenic, in rats. British journal of pharmacology. 2007 May:151(1):24-34     [PubMed PMID: 17351661]

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Chapple CR. A Comparison of Varying alpha-Blockers and Other Pharmacotherapy Options for Lower Urinary Tract Symptoms. Reviews in urology. 2005:7 Suppl 4(Suppl 4):S22-30     [PubMed PMID: 16986051]


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de Mey C. alpha(1)-blockers for BPH: are there differences? European urology. 1999:36 Suppl 3():52-63     [PubMed PMID: 10559631]

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[24]

By the 2019 American Geriatrics Society Beers Criteria® Update Expert Panel. American Geriatrics Society 2019 Updated AGS Beers Criteria® for Potentially Inappropriate Medication Use in Older Adults. Journal of the American Geriatrics Society. 2019 Apr:67(4):674-694. doi: 10.1111/jgs.15767. Epub 2019 Jan 29     [PubMed PMID: 30693946]


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Ungar A, Rafanelli M, Iacomelli I, Brunetti MA, Ceccofiglio A, Tesi F, Marchionni N. Fall prevention in the elderly. Clinical cases in mineral and bone metabolism : the official journal of the Italian Society of Osteoporosis, Mineral Metabolism, and Skeletal Diseases. 2013 May:10(2):91-5     [PubMed PMID: 24133524]

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Cain MP, Wu SD, Austin PF, Herndon CD, Rink RC. Alpha blocker therapy for children with dysfunctional voiding and urinary retention. The Journal of urology. 2003 Oct:170(4 Pt 2):1514-5; discussion 1516-7     [PubMed PMID: 14501648]


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Austin PF, Homsy YL, Masel JL, Cain MP, Casale AJ, Rink RC. alpha-Adrenergic blockade in children with neuropathic and nonneuropathic voiding dysfunction. The Journal of urology. 1999 Sep:162(3 Pt 2):1064-7     [PubMed PMID: 10458432]


[28]

Somberg JC, Achari R, Laddu AR. Terazosin: pharmacokinetics and the effect of age and dose on the incidence of adverse events. American heart journal. 1991 Sep:122(3 Pt 2):901-5     [PubMed PMID: 1678920]

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Maher RL, Hanlon J, Hajjar ER. Clinical consequences of polypharmacy in elderly. Expert opinion on drug safety. 2014 Jan:13(1):57-65. doi: 10.1517/14740338.2013.827660. Epub 2013 Sep 27     [PubMed PMID: 24073682]

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[30]

Lloyd SN, Buckley JF, Chilton CP, Ibrahim I, Kaisary AV, Kirk D. Terazosin in the treatment of benign prostatic hyperplasia: a multicentre, placebo-controlled trial. British journal of urology. 1992 Nov:70 Suppl 1():17-21     [PubMed PMID: 1281727]

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[31]

Oelke M, Becher K, Castro-Diaz D, Chartier-Kastler E, Kirby M, Wagg A, Wehling M. Appropriateness of oral drugs for long-term treatment of lower urinary tract symptoms in older persons: results of a systematic literature review and international consensus validation process (LUTS-FORTA 2014). Age and ageing. 2015 Sep:44(5):745-55. doi: 10.1093/ageing/afv077. Epub 2015 Jun 23     [PubMed PMID: 26104505]

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