Hytrin
Generic Name: terazosin hydrochloride
Dosage Form: Tablets
Description
Hytrin (terazosin hydrochloride), an alpha-1-selective
adrenoceptor blocking agent, is a quinazoline derivative represented by the
following chemical name and structural formula:
(RS)-Piperazine,
1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-[(tetra-hydro-2-furanyl)carbonyl]-,
monohydrochloride, dihydrate.

Terazosin hydrochloride is a white, crystalline substance,
freely soluble in water and isotonic saline and has a molecular weight of
459.93. Hytrin tablets (terazosin hydrochloride tablets) for oral ingestion
are supplied in four dosage strengths containing terazosin hydrochloride equivalent
to 1 mg, 2 mg, 5 mg, or 10 mg of terazosin.
Inactive Ingredients
1 mg tablet: corn starch, lactose, magnesium stearate,
povidone and talc.
2 mg tablet: corn starch,
FD&C Yellow No. 6, lactose, magnesium stearate, povidone and talc.
5 mg tablet: corn starch, iron oxide, lactose, magnesium
stearate, povidone and talc.
10 mg tablet:
corn starch, D&C Yellow No. 10, FD&C Blue No. 2, lactose, magnesium
stearate, povidone and talc.
Hytrin - Clinical Pharmacology
Pharmacodynamics
A. Benign Prostatic Hyperplasia (BPH)
The symptoms associated with BPH are related to
bladder outlet obstruction, which is comprised of two underlying components:
a static component and a dynamic component. The static component is a consequence
of an increase in prostate size. Over time, the prostate will continue to
enlarge. However, clinical studies have demonstrated that the size of the
prostate does not correlate with the severity of BPH symptoms or the degree
of urinary obstruction.1 The dynamic component is a function of
an increase in smooth muscle tone in the prostate and bladder neck, leading
to constriction of the bladder outlet. Smooth muscle tone is mediated by sympathetic
nervous stimulation of alpha-l adrenoceptors, which are abundant in the prostate,
prostatic capsule and bladder neck. The reduction in symptoms and improvement
in urine flow rates following administration of terazosin is related to relaxation
of smooth muscle produced by blockade of alpha-l adrenoceptors in the bladder
neck and prostate. Because there are relatively few alpha-l adrenoceptors
in the bladder body, terazosin is able to reduce the bladder outlet obstruction
without affecting bladder contractility.
Terazosin
has been extensively studied in 1222 men with symptomatic BPH. In three placebo-controlled
studies, symptom evaluation and uroflowmetric measurements were performed
approximately 24 hours following dosing. Symptoms were systematically quantified
using the Boyarsky Index. The questionnaire evaluated both obstructive (hesitancy,
intermittency, terminal dribbling, impairment of size and force of stream,
sensation of incomplete bladder emptying) and irritative (nocturia, daytime
frequency, urgency, dysuria) symptoms by rating each of the 9 symptoms from
0-3, for a total score of 27 points. Results from these studies indicated
that terazosin statistically significantly improved symptoms and peak urine
flow rates over placebo as follows:
|
Symptom
Score (Range 0-27) |
Peak
Flow Rate (mL/sec) |
|
N |
Mean Baseline |
Mean Change |
(%) |
N |
Mean Baseline |
Mean Change |
(%) |
|
a Highest dose 10 mg
shown.
b 23% of patients
on 10 mg, 41% of patients on 20 mg.
c 67% of patients on 10 mg.
* Significantly
(p ≤ 0.05) more improvement than placebo.
|
| Study 1 |
(10 mg)a
|
|
|
|
|
|
|
| Titration to fixed dose (12 wks) |
|
|
|
|
|
|
|
|
| Placebo |
55 |
9.7 |
-2.3 |
(24) |
54 |
10.1 |
+1.0 |
(10) |
| Terazosin |
54 |
10.1 |
-4.5 |
(45)* |
52 |
8.8 |
+3.0 |
(34)* |
| Study 2 |
(2, 5, 10, 20 mg)b
|
|
|
|
|
|
|
| Titration to response (24 wks) |
|
|
|
|
|
|
|
|
| Placebo |
89 |
12.5 |
-3.8 |
(30) |
88 |
8.8 |
+1.4 |
(16) |
| Terazosin |
85 |
12.2 |
-5.3 |
(43)* |
84 |
8.4 |
+2.9 |
(35)* |
| Study 3 |
(1, 2, 5, 10 mg)c
|
|
|
|
|
|
|
| Titration to response (24 wks) |
|
|
|
|
|
|
|
|
| Placebo |
74 |
10.4 |
-1.1 |
(11) |
74 |
8.8 |
+1.2 |
(14) |
| Terazosin |
73 |
10.9 |
-4.6 |
(42)* |
73 |
8.6 |
+2.6 |
(30)* |
In all three studies, both symptom scores and
peak urine flow rates showed statistically significant improvement from baseline
in patients treated with Hytrin from week 2 (or the first clinic visit) and
throughout the study duration.
Analysis of
the effect of Hytrin on individual urinary symptoms demonstrated that compared
to placebo, Hytrin significantly improved the symptoms of hesitancy, intermittency,
impairment in size and force of urinary stream, sensation of incomplete emptying,
terminal dribbling, daytime frequency and nocturia.
Global
assessments of overall urinary function and symptoms were also performed by
investigators who were blinded to patient treatment assignment. In studies
1 and 3, patients treated with Hytrin had a significantly (p ≤ 0.001)
greater overall improvement compared to placebo treated patients.
In a short term study (Study 1), patients were randomized
to either 2, 5 or 10 mg of Hytrin or placebo. Patients randomized to the 10
mg group achieved a statistically significant response in both symptoms and
peak flow rate compared to placebo (Figure 1).
Figure 1. Study 1
| Mean Change in
Total Symptom Score from Baseline+ |
Mean Increase
in Peak Flow Rate (mL/sec) from Baseline+ |
|
+ for
baseline values see above table
* p ≤
0.05, compared to placebo group
|
 |
In a long-term, open-label, non-placebo controlled
clinical trial, 181 men were followed for 2 years and 58 of these men were
followed for 30 months. The effect of Hytrin on urinary symptom scores and
peak flow rates was maintained throughout the study duration (Figures 2 and
3):
Figure 2. Mean
Change in Total Symptom Score from Baseline Long-term, Open-label, Non-placebo
Controlled Study (N = 494)

* p ≤ 0.05 vs. baseline
mean baseline = 10.7
Figure 3. Mean Change in Peak Flow Rate from Baseline
Long-term, Open-label, Non-placebo Controlled Study (N = 494)

* p≤ 0.05 vs. baseline
mean baseline
= 9.9
In this long-term trial, both symptom
scores and peak urinary flow rates showed statistically significant improvement
suggesting a relaxation of smooth muscle cells.
Although
blockade of alpha-1 adrenoceptors also lowers blood pressure in hypertensive
patients with increased peripheral vascular resistance, terazosin treatment
of normotensive men with BPH did not result in a clinically significant blood
pressure lowering effect:
Mean Changes in Blood Pressure from Baseline to Final Visit in all
Double-blind, Placebo-controlled Studies
|
|
Normotensive
Patients DBP ≤ 90 mm Hg |
Hypertensive
Patients DBP > 90 mm Hg |
|
Group |
N |
Mean Change |
N |
Mean Change |
* p ≤ 0.05 vs.
placebo |
| SBP |
Placebo |
293 |
-0.1 |
45 |
-5.8 |
| (mm Hg) |
Terazosin |
519 |
-3.3* |
65 |
-14.4* |
| DBP |
Placebo |
293 |
+0.4 |
45 |
-7.1 |
| (mm Hg) |
Terazosin |
519 |
-2.2* |
65 |
-15.1* |
B. Hypertension
In animals, terazosin causes a decrease in blood
pressure by decreasing total peripheral vascular resistance. The vasodilatory
hypotensive action of terazosin appears to be produced mainly by blockade
of alpha-1 adrenoceptors. Terazosin decreases blood pressure gradually within
15 minutes following oral administration.
Patients
in clinical trials of terazosin were administered once daily (the great majority)
and twice daily regimens with total doses usually in the range of 5-20 mg/day,
and had mild (about 77%, diastolic pressure 95-105 mmHg) or moderate (23%,
diastolic pressure 105-115 mmHg) hypertension. Because terazosin, like all
alpha antagonists, can cause unusually large falls in blood pressure after
the first dose or first few doses, the initial dose was 1 mg in virtually
all trials, with subsequent titration to a specified fixed dose or titration
to some specified blood pressure end point (usually a supine diastolic pressure
of 90 mmHg).
Blood pressure responses were
measured at the end of the dosing interval (usually 24 hours) and effects
were shown to persist throughout the interval, with the usual supine responses
5-10 mmHg systolic and 3.5-8 mmHg diastolic greater than placebo. The responses
in the standing position tended to be somewhat larger, by 1-3 mmHg, although
this was not true in all studies. The magnitude of the blood pressure responses
was similar to prazosin and less than hydrochlorothiazide (in a single study
of hypertensive patients). In measurements 24 hours after dosing, heart rate
was unchanged.
Limited measurements of peak
response (2-3 hours after dosing) during chronic terazosin administration
indicate that it is greater than about twice the trough (24 hour) response,
suggesting some attenuation of response at 24 hours, presumably due to a fall
in blood terazosin concentrations at the end of the dose interval. This explanation
is not established with certainty, however, and is not consistent with the
similarity of blood pressure response to once daily and twice daily dosing
and with the absence of an observed dose-response relationship over a range
of 5-20 mg, i.e., if blood concentrations had fallen to the point of providing
less than full effect at 24 hours, a shorter dosing interval or larger dose
should have led to increased response.
Further
dose response and dose duration studies are being carried out. Blood pressure
should be measured at the end of the dose interval; if response is not satisfactory,
patients may be tried on a larger dose or twice daily dosing regimen. The
latter should also be considered if possibly blood pressure-related side effects,
such as dizziness, palpitations, or orthostatic complaints, are seen within
a few hours after dosing.
The greater blood
pressure effect associated with peak plasma concentrations (first few hours
after dosing) appears somewhat more position-dependent (greater in the erect
position) than the effect of terazosin at 24 hours and in the erect position
there is also a 6-10 beat per minute increase in heart rate in the first few
hours after dosing. During the first 3 hours after dosing 12.5% of patients
had a systolic pressure fall of 30 mmHg or more from supine to standing, or
standing systolic pressure below 90 mmHg with a fall of at least 20 mmHg,
compared to 4% of a placebo group.
There
was a tendency for patients to gain weight during terazosin therapy. In placebo-controlled
monotherapy trials, male and female patients receiving terazosin gained a
mean of 1.7 and 2.2 pounds respectively, compared to losses of 0.2 and 1.2
pounds respectively in the placebo group. Both differences were statistically
significant.
During controlled clinical trials,
patients receiving terazosin monotherapy had a small but statistically significant
decrease (a 3% fall) compared to placebo in total cholesterol and the combined
low-density and very-low-density lipoprotein fractions. No significant changes
were observed in high-density lipoprotein fraction and triglycerides compared
to placebo.
Analysis of clinical laboratory
data following administration of terazosin suggested the possibility of hemodilution
based on decreases in hematocrit, hemoglobin, white blood cells, total protein
and albumin. Decreases in hematocrit and total protein have been observed
with alpha-blockade and are attributed to hemodilution.
Pharmacokinetics
Relative to solution, terazosin hydrochloride administered
as Hytrin tablets is essentially completely absorbed in man. Food had little
or no effect on the extent of absorption but food delayed the time to peak
concentration by about 1 hour. Terazosin has been shown to undergo minimal
hepatic first-pass metabolism and nearly all of the circulating dose is in
the form of parent drug. The plasma levels peak about one hour after dosing,
and then decline with a half-life of approximately 12 hours. In a study that
evaluated the effect of age on terazosin pharmacokinetics, the mean plasma
half-lives were 14.0 and 11.4 hours for the age group ≥ 70 years and
the age group of 20-39 years, respectively. After oral administration the
plasma clearance was decreased by 31.7% in patients 70 years of age or older
compared to that in patients 20-39 years of age.
The
drug is highly bound to plasma proteins and binding is constant over the clinically
observed concentration range. Approximately 10% of an orally administered
dose is excreted as parent drug in the urine and approximately 20% is excreted
in the feces. The remainder is eliminated as metabolites. Impaired renal function
had no significant effect on the elimination of terazosin, and dosage adjustment
of terazosin to compensate for the drug removal during hemodialysis (approximately
10%) does not appear to be necessary. Overall, approximately 40% of the administered
dose is excreted in the urine and approximately 60% in the feces. The disposition
of the compound in animals is qualitatively similar to that in man.
Indications and Usage for Hytrin
Hytrin (terazosin hydrochloride) is 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 Hytrin.
The long-term effects of Hytrin on the incidence of surgery, acute urinary
obstruction or other complications of BPH are yet to be determined.
Hytrin tablets are also indicated for the treatment of hypertension.
Hytrin tablets can be used alone or in combination with other antihypertensive
agents such as diuretics or beta-adrenergic blocking agents.
Contraindications
Hytrin tablets are contraindicated in patients known
to be hypersensitive to terazosin hydrochloride.
Warnings
Syncope and ‘‘First-dose’’ Effect
Hytrin tablets, 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 120-160 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 Hytrin tablets, given at bedtime.
The 2 mg, 5 mg and 10 mg tablets 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 Hytrin tablets 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
treated patients was 5.1%, 5.2%, and 3.7% respectively.
In multiple dose clinical trials involving nearly 2000 hypertensive
patients treated with Hytrin tablets, 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 Hytrin tablets
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 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. 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).
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 Hytrin 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 Hytrin tablets (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 Hytrin 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 Hytrin tablets,
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 Hytrin and other similar medications. Patients
should know that this reaction to Hytrin 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 Hytrin for up to 24 months
had no significant effect on prostate specific antigen (PSA) levels.
Drug Interactions
In controlled trials, Hytrin tablets have been added
to diuretics, and several beta-adrenergic blockers; no unexpected interactions
were observed. Hytrin tablets have also been used in patients on a variety
of concomitant therapies; while these were not formal interaction studies,
no interactions were observed. Hytrin tablets 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 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
Hytrin 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).
Hytrin, 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. Hytrin 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 Hytrin 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 Hytrin 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
Hytrin was 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. Hytrin is 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 Hytrin tablets are administered to a nursing woman.
Pediatric Use
Safety and effectiveness in children have not been
determined.
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) |
|
† Includes weakness,
tiredness, lassitude and fatigue.
*
p ≤ 0.05 comparison between groups.
|
| BODY AS A WHOLE |
|
|
| †Asthenia |
7.4%* |
3.3% |
| Flu Syndrome |
2.4% |
1.7% |
| Headache |
4.9% |
5.8% |
| CARDIOVASCULAR SYSTEM |
|
|
| Hypotension |
0.6% |
0.6% |
| Palpitations |
0.9% |
1.1% |
| Postural Hypotension |
3.9%* |
0.8% |
| Syncope |
0.6% |
0.0% |
| DIGESTIVE SYSTEM |
|
|
| Nausea |
1.7% |
1.1% |
| METABOLIC AND NUTRITIONAL DISORDERS |
|
|
| Peripheral Edema |
0.9% |
0.3% |
| Weight Gain |
0.5% |
0.0% |
| NERVOUS SYSTEM |
|
|
| Dizziness |
9.1%* |
4.2% |
| Somnolence |
3.6%* |
1.9% |
| Vertigo |
1.4% |
0.3% |
| RESPIRATORY SYSTEM |
|
|
| Dyspnea |
1.7% |
0.8% |
| Nasal Congestion/Rhinitis |
1.9%* |
0.0% |
| SPECIAL SENSES |
|
|
| Blurred Vision/Amblyopia |
1.3% |
0.6% |
| UROGENITAL SYSTEM |
|
|
| Impotence |
1.6%* |
0.6% |
| Urinary Tract Infection |
1.3% |
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 |
0.5% |
0.0% |
| Headache |
1.1% |
0.8% |
| CARDIOVASCULAR SYSTEM |
|
|
| Postural Hypotension |
0.5% |
0.0% |
| Syncope |
0.5% |
0.0% |
| DIGESTIVE SYSTEM |
|
|
| Nausea |
0.5% |
0.3% |
| NERVOUS SYSTEM |
|
|
| Dizziness |
2.0% |
1.1% |
| Vertigo |
0.5% |
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) |
|
† Includes weakness,
tiredness, lassitude and fatigue.
* Statistically
significant at p = 0.05 level.
|
| BODY AS A WHOLE |
|
|
| †Asthenia |
11.3%* |
4.3% |
| Back Pain |
2.4% |
1.2% |
| Headache |
16.2% |
15.8% |
| CARDIOVASCULAR SYSTEM |
|
|
| Palpitations |
4.3%* |
1.2% |
| Postural Hypotension |
1.3% |
0.4% |
| Tachycardia |
1.9% |
1.2% |
| DIGESTIVE SYSTEM |
|
|
| Nausea |
4.4%* |
1.4% |
| METABOLIC AND NUTRITIONAL DISORDERS |
|
|
| Edema |
0.9% |
0.6% |
| Peripheral Edema |
5.5%* |
2.4% |
| Weight Gain |
0.5% |
0.2% |
| MUSCULOSKELETAL SYSTEM |
|
|
| Pain-Extremities |
3.5% |
3.0% |
| NERVOUS SYSTEM |
|
|
| Depression |
0.3% |
0.2% |
| Dizziness |
19.3%* |
7.5% |
| Libido Decreased |
0.6% |
0.2% |
| Nervousness |
2.3% |
1.8% |
| Paresthesia |
2.9% |
1.4% |
| Somnolence |
5.4%* |
2.6% |
| RESPIRATORY SYSTEM |
|
|
| Dyspnea |
3.1% |
2.4% |
| Nasal Congestion |
5.9%* |
3.4% |
| Sinusitis |
2.6% |
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.
|