Terazosin Hydrochloride

Terazosin capsules, USP 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, USP. The long-term effects of terazosin capsules, USP on the incidence of surgery, acute urinary obstruction or other complications of BPH are yet to be determined. Terazosin capsules, USP are also indicated for the treatment of hypertension. Terazosin capsules, USP can be used alone or in combination with other antihypertensive agents such as diuretics or beta-adrenergic blocking agents.

Terazosin capsules are contraindicated in patients known to be hypersensitive to terazosin hydrochloride.

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 capsules 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 (see CLINICAL PHARMACOLOGY ), the incidence of postural hypotension in the terazosin capsules, 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 capsules 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, (probably less than once in every several thousand patients), terazosin and other α 1 -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. Because this condition can lead to permanent impotence if not promptly treated, patients must be advised about the seriousness of the condition (see PRECAUTIONS: Information for Patients ).

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 capsules (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 Patient (See PATIENT INFORMATION.) 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 capsule 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 capsules, 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 capsules have been added to diuretics, and several beta-adrenergic blockers; no unexpected interactions were observed. Terazosin capsules have also been used in patients on a variety of concomitant therapies; while these were not formal interaction studies, no interactions were observed. Terazosin capsules have been used concomitantly in at least 50 patients on the following drugs or drug classes: 1. analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); 2. antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); 3. anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); 4. antigout (e.g., allopurinol); 5. antihistamines (e.g., chlorpheniramine); 6. cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); 7. corticosteroids; 8. gastrointestinal agents (e.g., antacids); 9. hypoglycemics; 10. 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 AUC 0-24 increased 11% after the first verapamil dose and after 3 weeks of verapamil treatment it increased by 24% with associated increases in C max (25%) and C min (32%) means. Terazosin mean T max 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 capsules were 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 capsules, administered in the feed to rats at doses of 8, 40, and 250 mg/kg/day (70, 350, and 2100 mg/M 2 /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/M 2 ). Female rats were unaffected. Terazosin capsules were not oncogenic in mice when administered in feed for 2 years at a maximum tolerated dose of 32 mg/kg/day (110 mg/M 2 ; 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 capsules 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/M 2 ; 20 times the maximum recommended human dose) and five of 19 male rats given 120 mg/kg (960 mg/M 2 ; 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 capsules 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). […]

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 capsules 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 capsules than in patients receiving placebo. The incidence of urinary tract infection was significantly lower in the patients receiving terazosin capsules 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 1 Asthenia Flu Syndrome Headache 7.4% 2 2.4% 4.9% 3.3% 1.7% 5.8% CARDIOVASCULAR SYSTEM Hypotension Palpitations Postural Hypotension Syncope 0.6% 0.9% 3.9% 2 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% 2 3.6% 2 1.4% 4.2% 1.9% 0.3% RESPIRATORY SYSTEM Dyspnea Nasal Congestion/Rhinitis 1.7% 1.9% 2 0.8% 0.0% SPECIAL SENSES Blurred Vision/Amblyopia 1.3% 0.6% UROGENITAL SYSTEM Impotence Urinary Tract Infection 1.6% 2 1.3% 0.6% 3.9% 2 $FootNote 1 Includes weakness, tiredness, lassitude, and fatigue. 2 p ≤ 0.05 comparison between groups. $EndFootNote 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 capsules, 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 capsules 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 capsules. 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 studies 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. Discontinuation During Placebo-Controlled Trials Hypertension Body System Terazosin (N = 859) Placebo (N = 506) BODY AS A WHOLE Asthenia Headache 1.6% 1.3% 0.0% 1.0% CARDIOVASCULAR SYSTEM Palpitations Postural Hypotension Syncope Tachycardia 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 Paresthesia Somnolence 3.1% 0.8% 0.6% 0.4% 0.2% 0.2% RESPIRATORY SYSTEM Dyspnea Nasal 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. […]

In controlled trials, terazosin capsules have been added to diuretics, and several beta-adrenergic blockers; no unexpected interactions were observed. Terazosin capsules have also been used in patients on a variety of concomitant therapies; while these were not formal interaction studies, no interactions were observed. Terazosin capsules have been used concomitantly in at least 50 patients on the following drugs or drug classes: 1. analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); 2. antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); 3. anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); 4. antigout (e.g., allopurinol); 5. antihistamines (e.g., chlorpheniramine); 6. cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); 7. corticosteroids; 8. gastrointestinal agents (e.g., antacids); 9. hypoglycemics; 10. sedatives and tranquilizers (e.g., diazepam).

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.

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.

Safety and effectiveness in pediatric patients have not been determined.