Data from FDA - Curated by EPG Health - Last updated 22 November 2019

Indication(s)

INDICATIONS AND USAGE Terazosin capsules are indicated for the treatment of symptomatic benign prostatic hyperplasia (BPH). There is a rapid response, with approximately 70% of patients experiencing an increase in urinary flow and improvement in symptoms of BPH when treated with terazosin capsules. The long-term effects of terazosin capsules on the incidence of surgery, acute urinary obstruction or other complications of BPH are yet to be determined. Terazosin capsules are also indicated for the treatment of hypertension. Terazosin capsules can be used alone or in combination with other antihypertensive agents such as diuretics or beta-adrenergic blocking agents.

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Advisory information

contraindications
CONTRAINDICATIONS Terazosin capsules are contraindicated in patients known to be hypersensitive to terazosin hydrochloride.
Special warnings and precautions
PRECAUTIONS General Prostatic Cancer Carcinoma of the prostate and BPH cause many of the same symptoms. These two diseases frequently co-exist. Therefore, patients thought to have BPH should be examined prior to starting terazosin capsule therapy to rule out the presence of carcinoma of the prostate. Intraoperative Floppy Iris Syndrome (IFIS) Intraoperative Floppy Iris Syndrome (IFIS) has been observed during cataract surgery in some patients on/or previously treated with alpha-1 blockers. This variant of small pupil syndrome is characterized by the combination of a flaccid iris that billows in response to intraoperative irrigation currents, progressive intraoperative miosis despite preoperative dilation with standard mydriatic drugs, and potential prolapse of the iris toward the phacoemulsification incisions. The patient’s ophthalmologist should be prepared for possible modifications to their surgical technique, such as the utilization of iris hooks, iris dilator rings, or viscoelastic substances. There does not appear to be a benefit of stopping alpha-1 blocker therapy prior to cataract surgery. Orthostatic Hypotension While syncope is the most severe orthostatic effect of terazosin (see WARNINGS ), other symptoms of lowered blood pressure, such as dizziness, lightheadedness and palpitations, were more common and occurred in some 28% of patients in clinical trials of hypertension. In BPH clinical trials, 21% of the patients experienced one or more of the following: dizziness, hypotension, postural hypotension, syncope, and vertigo. Patients with occupations in which such events represent potential problems should be treated with particular caution. Information for Patients (see Patient Package Insert) Patients should be made aware of the possibility of syncopal and orthostatic symptoms, especially at the initiation of therapy, and to avoid driving or hazardous tasks for 12 hours after the first dose, after a dosage increase, and after interruption of therapy when treatment is resumed. They should be cautioned to avoid situations where injury could result should syncope occur during initiation of terazosin therapy. They should also be advised of the need to sit or lie down when symptoms of lowered blood pressure occur, although these symptoms are not always orthostatic, and to be careful when rising from a sitting or lying position. If dizziness, lightheadedness, or palpitations are bothersome they should be reported to the physician, so that dose adjustment can be considered. Patients should also be told that drowsiness or somnolence can occur with terazosin, requiring caution in people who must drive or operate heavy machinery. Patients should be advised about the possibility of priapism as a result of treatment with terazosin capsules and other similar medications. Patients should know that this reaction to terazosin capsules is extremely rare, but that if it is not brought to immediate medical attention, it can lead to permanent erectile dysfunction (impotence). Laboratory Tests Small but statistically significant decreases in hematocrit, hemoglobin, white blood cells, total protein and albumin were observed in controlled clinical trials. These laboratory findings suggested the possibility of hemodilution. Treatment with terazosin capsules for up to 24 months had no significant effect on prostate specific antigen (PSA) levels. Drug Interactions In controlled trials, terazosin have been added to diuretics, and several beta-adrenergic blockers; no unexpected interactions were observed. Terazosin has also been used in patients on a variety of concomitant therapies; while these were not formal interaction studies, no interactions were observed. Terazosin has been used concomitantly in at least 50 patients on the following drugs or drug classes: analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); antigout (e.g., allopurinol); antihistamines (e.g., chlorpheniramine); cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); corticosteroids; gastrointestinal agents (e.g., antacids); hypoglycemics; sedatives and tranquilizers (e.g., diazepam). Use With Other Drugs In a study (n=24) where terazosin and verapamil were administered concomitantly, terazosin’s mean AUC0-24 increased 11% after the first verapamil dose and after 3 weeks of verapamil treatment it increased by 24% with associated increases in Cmax (25%) and Cmin (32%) means. Terazosin mean Tmax decreased from 1.3 hours to 0.8 hours after 3 weeks of verapamil treatment. Statistically significant differences were not found in the verapamil level with and without terazosin. In a study (n=6) where terazosin and captopril were administered concomitantly, plasma disposition of captopril was not influenced by concomitant administration of terazosin and terazosin maximum plasma concentrations increased linearly with dose at steady-state after administration of terazosin plus captopril (see DOSAGE AND ADMINISTRATION ). Carcinogenesis, Mutagenesis, Impairment of Fertility : Terazosin was devoid of mutagenic potential when evaluated in vivo and in vitro (the Ames test, in vivo cytogenetics, the dominant lethal test in mice, in vivo Chinese hamster chromosome aberration test and V79 forward mutation assay). Terazosin administered in the feed to rats at doses of 8, 40, and 250 mg/kg/day (70, 350, and 2100 mg/M2/day), for two years, was associated with a statistically significant increase in benign adrenal medullary tumors of male rats exposed to the 250 mg/kg dose. This dose is 175 times the maximum recommended human dose of 20 mg (12 mg/M2). Female rats were unaffected. Terazosin was not oncogenic in mice when administered in feed for 2 years at a maximum tolerated dose of 32 mg/kg/day (110 mg/M2; 9 times the maximum recommended human dose). The absence of mutagenicity in a battery of tests, of tumorigenicity of any cell type in the mouse carcinogenicity assay, of increased total tumor incidence in either species, and of proliferative adrenal lesions in female rats, suggests a male rat species-specific event. Numerous other diverse pharmaceutical and chemical compounds have also been associated with benign adrenal medullary tumors in male rats without supporting evidence for carcinogenicity in man. The effect of terazosin on fertility was assessed in a standard fertility/reproductive performance study in which male and female rats were administered oral doses of 8, 30 and 120 mg/kg/day. Four of 20 male rats given 30 mg/kg (240 mg/M2; 20 times the maximum recommended human dose) and five of 19 male rats given 120 mg/kg (960 mg/M2; 80 times the maximum recommended human dose) failed to sire a litter. Testicular weights and morphology were unaffected by treatment. Vaginal smears at 30 and 120 mg/kg/day, however, appeared to contain less sperm than smears from control matings and good correlation was reported between sperm count and subsequent pregnancy. Oral administration of terazosin for one or two years elicited a statistically significant increase in the incidence of testicular atrophy in rats exposed to 40 and 250 mg/kg/day (29 and 175 times the maximum recommended human dose), but not in rats exposed to 8 mg/kg/day (> 6 times the maximum recommended human dose). Testicular atrophy was also observed in dogs dosed with 300 mg/kg/day (> 500 times the maximum recommended human dose) for three months but not after one year when dosed with 20 mg/kg/day (38 times the maximum recommended human dose). This lesion has also been seen with Minipress®, another (marketed) selective-alpha-1 blocking agent. Pregnancy Teratogenic Effects : Pregnancy Category C Terazosin capsules were not teratogenic in either rats or rabbits when administered at oral doses up to 280 and 60 times, respectively, the maximum recommended human dose. Fetal resorptions occurred in rats dosed with 480 mg/kg/day, approximately 280 times the maximum recommended human dose. Increased fetal resorptions, decreased fetal weight and an increased number of supernumerary ribs were observed in offspring of rabbits dosed with 60 times the maximum recommended human dose. These findings (in both species) were most likely secondary to maternal toxicity. There are no adequate and well-controlled studies in pregnant women and the safety of terazosin in pregnancy has not been established. Terazosin capsules are not recommended during pregnancy unless the potential benefit justifies the potential risk to the mother and fetus. Nonteratogenic Effects : In a peri- and post-natal development study in rats, significantly more pups died in the group dosed with 120 mg/kg/day (> 75 times the maximum recommended human dose) than in the control group during the three-week postpartum period. Nursing Mothers : It is not known whether terazosin is excreted in breast milk. Because many drugs are excreted in breast milk, caution should be exercised when terazosin capsules are administered to a nursing woman. Pediatric Use : Safety and effectiveness in pediatric patients have not been determined.
Adverse reactions
ADVERSE REACTIONS Benign Prostatic Hyperplasia The incidence of treatment-emergent adverse events has been ascertained from clinical trials conducted worldwide. All adverse events reported during these trials were recorded as adverse reactions. The incidence rates presented below are based on combined data from six placebo-controlled trials involving once-a-day administration of terazosin at doses ranging from 1 to 20 mg. Table 1 summarizes those adverse events reported for patients in these trials when the incidence rate in the terazosin group was at least 1%, and was greater than that for the placebo group, or where the reaction is of clinical interest. Asthenia, postural hypotension, dizziness, somnolence, nasal congestion/rhinitis, and impotence were the only events that were significantly (p ≤ 0.05) more common in patients receiving terazosin than in patients receiving placebo. The incidence of urinary tract infection was significantly lower in the patients receiving terazosin than in patients receiving placebo. An analysis of the incidence rate of hypotensive adverse events (see PRECAUTIONS ) adjusted for the length of drug treatment has shown that the risk of the events is greatest during the initial seven days of treatment, but continues at all time intervals. TABLE 1. Adverse Reactions During Placebo-Controlled Trials Benign Prostatic Hyperplasia Body System Terazosin (N = 636) Placebo (N = 360) BODY AS A WHOLE Includes weakness, tiredness, lassitude, and fatigue.Asthenia Flu Syndrome Headache 7.4%p ≤ 0.05 comparison between groups. 2.4% 4.9% 3.3% 1.7% 5.8% CARDIOVASCULAR SYSTEM Hypotension Palpitations Postural Hypotension Syncope 0.6% 0.9% 3.9% 0.6% 0.6% 1.1% 0.8% 0.0% DIGESTIVE SYSTEM Nausea 1.7% 1.1% METABOLIC AND NUTRITIONAL DISORDERS Peripheral Edema Weight Gain 0.9% 0.5% 0.3% 0.0% NERVOUS SYSTEM Dizziness Somnolence Vertigo 9.1% 3.6% 1.4% 4.2% 1.9% 0.3% RESPIRATORY SYSTEM Dyspnea Nasal Congestion/Rhinitis 1.7% 1.9% 0.8% 0.0% SPECIAL SENSES Blurred Vision/Amblyopia 1.3% 0.6% UROGENITAL SYSTEM Impotence Urinary Tract Infection 1.6% 1.3% 0.6% 3.9% Additional adverse events have been reported, but these are, in general, not distinguishable from symptoms that might have occurred in the absence of exposure to terazosin. The safety profile of patients treated in the long-term open-label study was similar to that observed in the controlled studies. The adverse events were usually transient and mild or moderate in intensity, but sometimes were serious enough to interrupt treatment. In the placebo-controlled clinical trials, the rates of premature termination due to adverse events were not statistically different between the placebo and terazosin groups. The adverse events that were bothersome, as judged by their being reported as reasons for discontinuation of therapy by at least 0.5% of the terazosin group and being reported more often than in the placebo group, are shown in Table 2. TABLE 2. Discontinuation During Placebo-Controlled Trials Benign Prostatic Hyperplasia Body System Terazosin (N = 636) Placebo (N = 360) BODY AS A WHOLE Fever Headache 0.5%1.1% 0.0%0.8% CARDIOVASCULAR SYSTEM Postural Hypotension Syncope 0.5%0.5% 0.0%0.0% DIGESTIVE SYSTEM Nausea 0.5% 0.3% NERVOUS SYSTEM Dizziness Vertigo 2.0%0.5% 1.1%0.0% RESPIRATORY SYSTEM Dyspnea 0.5% 0.3% SPECIAL SENSES Blurred Vision/Amblyopia 0.6% 0.0% UROGENITAL SYSTEM Urinary Tract Infection 0.5% 0.3% Hypertension The prevalence of adverse reactions has been ascertained from clinical trials conducted primarily in the United States. All adverse experiences (events) reported during these trials were recorded as adverse reactions. The prevalence rates presented below are based on combined data from fourteen placebo-controlled trials involving once-a-day administration of terazosin, as monotherapy or in combination with other antihypertensive agents, at doses ranging from 1 to 40 mg. Table 3 summarizes those adverse experiences reported for patients in these trials where the prevalence rate in the terazosin group was at least 5%, where the prevalence rate for the terazosin group was at least 2% and was greater than the prevalence rate for the placebo group, or where the reaction is of particular interest. Asthenia, blurred vision, dizziness, nasal congestion, nausea, peripheral edema, palpitations and somnolence were the only symptoms that were significantly (p < 0.05) more common in patients receiving terazosin than in patients receiving placebo. Similar adverse reaction rates were observed in placebo-controlled monotherapy trials. TABLE 3. Adverse Reactions During Placebo-Controlled Trials Hypertension Body System Terazosin (N = 859) Placebo (N = 506) BODY AS A WHOLE Includes weakness, tiredness, lassitude, and fatigue.Asthenia Back Pain Headache 11.3%Statistically significant at p=0.05 level. 2.4% 16.2% 4.3% 1.2%15.8% CARDIOVASCULAR SYSTEM Palpitations Postural Hypotension Tachycardia 4.3% 1.3% 1.9% 1.2% 0.4%1.2% DIGESTIVE SYSTEM Nausea 4.4% 1.4% METABOLIC AND NUTRITIONAL DISORDERS Edema Peripheral Edema Weight Gain 0.9% 5.5% 0.5% 0.6% 2.4%0.2% MUSCULOSKELETAL SYSTEM Pain – Extremities 3.5% 3.0% NERVOUS SYSTEM Depression Dizziness Libido Decreased Nervousness Paresthesia Somnolence 0.3% 19.3% 0.6% 2.3% 2.9% 5.4% 0.2% 7.5% 0.2% 1.8% 1.4%2.6% RESPIRATORY SYSTEM Dyspnea Nasal Congestion Sinusitis 3.1% 5.9% 2.6% 2.4% 3.4%1.4% SPECIAL SENSES Blurred Vision 1.6% 0.0% UROGENITAL SYSTEM Impotence 1.2% 1.4% Additional adverse reactions have been reported, but these are, in general, not distinguishable from symptoms that might have occurred in the absence of exposure to terazosin. The following additional adverse reactions were reported by at least 1% of 1987 patients who received terazosin in controlled or open, short- or long-term clinical trials or have been reported during marketing experience: Body as a Whole : Chest pain, facial edema, fever, abdominal pain, neck pain, shoulder pain. Cardiovascular System : Arrhythmia, vasodilation. Digestive System : Constipation, diarrhea, dry mouth, dyspepsia, flatulence, vomiting. Metabolic/Nutritional Disorders Gout. Musculoskeletal System : Arthralgia, arthritis, joint disorder, myalgia. Nervous System : Anxiety, insomnia. Respiratory System : Bronchitis, cold symptoms, epistaxis, flu symptoms, increased cough, pharyngitis, rhinitis. Skin and Appendages : Pruritus, rash, sweating. Special Senses : Abnormal vision, conjunctivitis, tinnitus. Urogenital System : Urinary frequency, urinary incontinence primarily reported in postmenopausal women, urinary tract infection. The adverse reactions were usually mild or moderate in intensity but sometimes were serious enough to interrupt treatment. The adverse reactions that were most bothersome, as judged by their being reported as reasons for discontinuation of therapy by at least 0.5% of the terazosin group and being reported more often than in the placebo group, are shown in Table 4. TABLE 4. Discontinuations During Placebo-Controlled Trials Hypertension Body System Terazosin (N = 859) Placebo (N = 506) BODY AS A WHOLE AstheniaHeadache 1.6% 1.3% 0.0% 1.0% CARDIOVASCULAR SYSTEM Palpitations Postural Hypotension SyncopeTachycardia 1.4% 0.5% 0.5%0.6% 0.2% 0.0% 0.2%0.0% DIGESTIVE SYSTEM Nausea 0.8% 0.0% METABOLIC AND NUTRITIONAL DISORDERS Peripheral Edema 0.6% 0.0% NERVOUS SYSTEM Dizziness ParesthesiaSomnolence 3.1% 0.8%0.6% 0.4% 0.2%0.2% RESPIRATORY SYSTEM DyspneaNasal Congestion 0.9% 0.6% 0.6% 0.0% SPECIAL SENSES Blurred Vision 0.6% 0.0% Post-marketing 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 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 (see PRECAUTIONS ).

Usage information

Dosing and administration
DOSAGE AND ADMINISTRATION If terazosin capsules administration is discontinued for several days, therapy should be reinstituted using the initial dosing regimen. Benign Prostatic Hyperplasia Initial Dose : 1 mg at bedtime is the starting dose for all patients, and this dose should not be exceeded as an initial dose. Patients should be closely followed during initial administration in order to minimize the risk of severe hypotensive response. Subsequent Doses : The dose should be increased in a stepwise fashion to 2 mg, 5 mg, or 10 mg once daily to achieve the desired improvement of symptoms and/or flow rates. Doses of 10 mg once daily are generally required for the clinical response. Therefore, treatment with 10 mg for a minimum of 4 to 6 weeks may be required to assess whether a beneficial response has been achieved. Some patients may not achieve a clinical response despite appropriate titration. Although some additional patients responded at a 20 mg daily dose, there was an insufficient number of patients studied to draw definitive conclusions about this dose. There are insufficient data to support the use of higher doses for those patients who show inadequate or no response to 20 mg daily. If terazosin administration is discontinued for several days or longer, therapy should be reinstituted using the initial dosing regimen. Use With Other Drugs : Caution should be observed when terazosin capsules are administered concomitantly with other antihypertensive agents, especially the calcium channel blocker verapamil, to avoid the possibility of developing significant hypotension. When using terazosin capsules and other antihypertensive agents concomitantly, dosage reduction and retitration of either agent may be necessary (see PRECAUTIONS ). Hypotension has been reported when terazosin capsules have been used with phosphodiesterase-5 (PDE-5) inhibitors. Hypertension The dose of terazosin capsules and the dose interval (12 or 24 hours) should be adjusted according to the patient’s individual blood pressure response. The following is a guide to its administration: Initial Dose 1 mg at bedtime is the starting dose for all patients, and this dose should not be exceeded. This initial dosing regimen should be strictly observed to minimize the potential for severe hypotensive effects. Subsequent Doses The dose may be slowly increased to achieve the desired blood pressure response. The usual recommended dose range is 1 mg to 5 mg administered once a day; however, some patients may benefit from doses as high as 20 mg per day. Doses over 20 mg do not appear to provide further blood pressure effect and doses over 40 mg have not been studied. Blood pressure should be monitored at the end of the dosing interval to be sure control is maintained throughout the interval. It may also be helpful to measure blood pressure 2 to 3 hours after dosing to see if the maximum and minimum responses are similar, and to evaluate symptoms such as dizziness or palpitations which can result from excessive hypotensive response. If response is substantially diminished at 24 hours an increased dose or use of a twice daily regimen can be considered. If terazosin administration is discontinued for several days or longer, therapy should be reinstituted using the initial dosing regimen. In clinical trials, except for the initial dose, the dose was given in the morning. Use With Other Drugs (See above.)
Pregnancy and lactation
Nursing Mothers : It is not known whether terazosin is excreted in breast milk. Because many drugs are excreted in breast milk, caution should be exercised when terazosin capsules are administered to a nursing woman.

Interactions

Drug Interactions In controlled trials, terazosin have been added to diuretics, and several beta-adrenergic blockers; no unexpected interactions were observed. Terazosin has also been used in patients on a variety of concomitant therapies; while these were not formal interaction studies, no interactions were observed. Terazosin has been used concomitantly in at least 50 patients on the following drugs or drug classes: analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); antigout (e.g., allopurinol); antihistamines (e.g., chlorpheniramine); cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); corticosteroids; gastrointestinal agents (e.g., antacids); hypoglycemics; sedatives and tranquilizers (e.g., diazepam).

More information

Category Value
Authorisation number ANDA075317
Agency product number D32S14F082
Orphan designation No
Product NDC 50090-2371
Date Last Revised 09-10-2019
Type HUMAN PRESCRIPTION DRUG
RXCUI 260376
Marketing authorisation holder A-S Medication Solutions