Terazosin
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
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Overview
Terazosin is a alpha-adrenergic blocker that is FDA approved for the {{{indicationType}}} of symptomatic benign prostatic hyperplasia (BPH) and hypertension. Common adverse reactions include orthostatic hypotension, palpitations, peripheral edema, nausea, asthenia, dizziness headache, somnolence and nasal congestion.
Adult Indications and Dosage
FDA-Labeled Indications and Dosage (Adult)
Condition 1
- Dosing Information
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Condition 2
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Off-Label Use and Dosage (Adult)
Guideline-Supported Use
Condition 1
- Developed by: (Organisation)
- Class of Recommendation: (Class) (Link)
- Strength of Evidence: (Category A/B/C) (Link)
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Condition 2
- Developed by: (Organisation)
- Class of Recommendation: (Class) (Link)
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Non–Guideline-Supported Use
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Condition 3
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Pediatric Indications and Dosage
FDA-Labeled Indications and Dosage (Pediatric)
Condition 1
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Condition 2
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Off-Label Use and Dosage (Pediatric)
Guideline-Supported Use
Condition 1
- Developed by: (Organisation)
- Class of Recommendation: (Class) (Link)
- Strength of Evidence: (Category A/B/C) (Link)
- Dosing Information/Recommendation
- (Dosage)
Condition 2
- Developed by: (Organisation)
- Class of Recommendation: (Class) (Link)
- Strength of Evidence: (Category A/B/C) (Link)
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Non–Guideline-Supported Use
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Condition 3
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Contraindications
- Terazosin capsules are contraindicated in patients known to be hypersensitive to terazosin hydrochloride.
Warnings
Syncope and “first-dose” effect
- Terazosin capsules, like other alpha-adrenergic blocking agents, can cause marked lowering of blood pressure, especially postural hypotension, and syncope in association with the first dose or first few days of therapy. A similar effect can be anticipated if therapy is interrupted for several days and then restarted.
- Syncope has also been reported with other alpha-adrenergic blocking agents in association with rapid dosage increases or the introduction of another antihypertensive drug.
- Syncope is believed to be due to an excessive postural hypotensive effect, although occasionally the syncopal episode has been preceded by a bout of severe supraventricular tachycardia with heart rates of 120 to 160 beats per minute. Additionally, the possibility of the contribution of hemodilution to the symptoms of postural hypotension should be considered.
- To decrease the likelihood of syncope or excessive hypotension, treatment should:
- Always be initiated with a 1 mg dose of terazosin capsules, given at bedtime.
- The 2 mg, 5 mg and 10 mg capsules are not indicated as initial therapy.
- Dosage should then be increased slowly, according to recommendations in the Dosage and Administration section and additional antihypertensive agents should be added with caution.
- The patient should be cautioned to avoid situations, such as driving or hazardous tasks, where injury could result should syncope occur during initiation of therapy.
In early investigational studies, where increasing single doses up to 7.5 mg were given at 3 day intervals, tolerance to the first dose phenomenon did not necessarily develop and the “first-dose” effect could be observed at all doses. Syncopal episodes occurred in 3 of the 14 subjects given terazosin at doses of 2.5, 5 and 7.5 mg, which are higher than the recommended initial dose; in addition, severe orthostatic hypotension (blood pressure falling to 50/0 mmHg) was seen in two others and dizziness, tachycardia, and lightheadedness occurred in most subjects. These adverse effects all occurred within 90 minutes of dosing. In three placebo-controlled BPH studies 1, 2, and 3, the incidence of postural hypotension in the terazosin treated patients was 5.1%, 5.2%, and 3.7% respectively. In multiple dose clinical trials involving nearly 2000 hypertensive patients treated with terazosin capsules, syncope was reported in about 1% of patients. Syncope was not necessarily associated only with the first dose. If syncope occurs, the patient should be placed in a recumbent position and treated supportively as necessary. There is evidence that the orthostatic effect of terazosin is greater, even in chronic use, shortly after dosing. The risk of the events is greatest during the initial seven days of treatment, but continues at all time intervals.
Priapism
- Rarely, terazosin and other α1-antagonists have been associated with priapism (painful penile erection, sustained for hours and unrelieved by sexual intercourse or masturbation). Two or three dozen cases have been reported.
- Since this condition can lead to permanent impotence if not promptly treated, patients must be advised about the seriousness of the condition.
Adverse Reactions
Clinical Trials Experience
Benign Prostatic Hyperplasia
Hypertension
Central Nervous System
- (list/description of adverse reactions)
Cardiovascular
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Respiratory
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Gastrointestinal
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Hypersensitive Reactions
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Miscellaneous
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Condition 2
Central Nervous System
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Cardiovascular
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Respiratory
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Gastrointestinal
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Hypersensitive Reactions
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Miscellaneous
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Postmarketing Experience
- Post-marketing experience indicates that in rare instances patients may develop allergic reactions, including anaphylaxis, following administration of terazosin hydrochloride.
- There have been reports of priapism and thrombocytopenia during post-marketing surveillance.
- Atrial fibrillation has also been reported.
- During cataract surgery, a variant of small pupil syndrome known as Intraoperative Floppy Iris Syndrome (IFIS) has been reported in association with alpha-1 blocker therapy.
Drug Interactions
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Drug 1
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Drug 2
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Drug 3
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Drug 4
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Drug 5
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Use in Specific Populations
Pregnancy
Pregnancy Category (FDA):
(Description)
Pregnancy Category (AUS):
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Labor and Delivery
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Nursing Mothers
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Pediatric Use
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Geriatic Use
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Gender
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Race
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Renal Impairment
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Hepatic Impairment
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Females of Reproductive Potential and Males
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Immunocompromised Patients
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Others
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Administration and Monitoring
Administration
(Oral/Intravenous/etc)
Monitoring
Condition 1
(Description regarding monitoring, from Warnings section)
Condition 2
(Description regarding monitoring, from Warnings section)
Condition 3
(Description regarding monitoring, from Warnings section)
IV Compatibility
Solution
Compatible
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Not Tested
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Variable
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Incompatible
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Y-Site
Compatible
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Not Tested
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Variable
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Incompatible
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Admixture
Compatible
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Not Tested
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Variable
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Incompatible
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Syringe
Compatible
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Not Tested
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Variable
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Incompatible
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TPN/TNA
Compatible
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Not Tested
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Variable
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Incompatible
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Overdosage
Acute Overdose
Signs and Symptoms
(Description)
Management
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Chronic Overdose
Signs and Symptoms
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Management
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Pharmacology
Terazosin
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Mechanism of Action
(Description)
Structure
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Pharmacodynamics
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Pharmacokinetics
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Nonclinical Toxicology
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Clinical Studies
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Condition 2
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Condition 3
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How Supplied
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Storage
There is limited information regarding Terazosin Storage in the drug label.
Images
Drug Images
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Package and Label Display Panel
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Patient Counseling Information
(Patient Counseling Information)
Precautions with Alcohol
Alcohol-Terazosin interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
Brand Names
- Hytrin
Look-Alike Drug Names
- (Paired Confused Name 1a) — (Paired Confused Name 1b)
- (Paired Confused Name 2a) — (Paired Confused Name 2b)
- (Paired Confused Name 3a) — (Paired Confused Name 3b)
Drug Shortage Status
Drug Shortage
Price
References
The contents of this FDA label are provided by the National Library of Medicine.