PRECAUTIONS General
Impaired Renal Function: As a consequence of
inhibiting the renin-angiotensin-aldosterone system, changes in renal function
may be anticipated in susceptible individuals. In patients with severe
congestive heart failure whose renal function may depend on the activity of the
renin-angiotensin-aldosterone system, treatment with angiotensin-converting
enzyme inhibitors, including benazepril hydrochloride, may be associated with
oliguria and/or progressive azotemia and (rarely) with acute renal failure
and/or death. In a small study of hypertensive patients with renal artery
stenosis in a solitary kidney or bilateral renal artery stenosis, treatment with
benazepril hydrochloride was associated with increases in blood urea nitrogen
and serum creatinine; these increases were reversible upon discontinuation of
Benazepril hydrochloride or diuretic therapy, or both. When such patients are
treated with ACE inhibitors, renal function should be monitored during the first
few weeks of therapy. Some hypertensive patients with no apparent preexisting
renal vascular disease have developed increases in blood urea nitrogen and serum
creatinine, usually minor and transient, especially when Benazepril
hydrochloride has been given concomitantly with a diuretic. This is more likely
to occur in patients with preexisting renal impairment. Dosage reduction of
Benazepril hydrochloride and/or discontinuation of the diuretic may be required.
Evaluation of the hypertensive patient should always include
assessment of renal function (see DOSAGE AND
ADMINISTRATION).
Hyperkalemia: In clinical trials, hyperkalemia
(serum potassium at least 0.5 mEq/L greater than the upper limit of normal)
occurred in approximately 1% of hypertensive patients receiving benazepril
hydrochloride. In most cases, these were isolated values which resolved despite
continued therapy. Risk factors for the development of hyperkalemia include
renal insufficiency, diabetes mellitus, and the concomitant use of
potassium-sparing diuretics, potassium supplements, and/or potassium-containing
salt substitutes, which should be used cautiously, if at all, with Benazepril
hydrochloride (see Drug
Interactions).
Cough: Presumably due to the inhibition of the
degradation of endogenous bradykinin, persistent nonproductive cough has been
reported with all ACE inhibitors, always resolving after discontinuation of
therapy. ACE inhibitor-induced cough should be considered in the differential
diagnosis of cough.
Impaired Liver Function: In patients with
hepatic dysfunction due to cirrhosis, levels of benazeprilat are essentially
unaltered (see WARNINGS, Hepatic
Failure).
Surgery/Anesthesia: In patients undergoing
surgery or during anesthesia with agents that produce hypotension, benazepril
will block the angiotensin II formation that could otherwise occur secondary to
compensatory renin release. Hypotension that occurs as a result of this
mechanism can be corrected by volume expansion.
Information for Patients Pregnancy: Female patients of
childbearing age should be told about the consequences of exposure to ACE
inhibitors. Discuss other treatment options with women planning to become
pregnant. Patients should be asked to report pregnancies to their physicians as
soon as possible.
Angioedema: Angioedema, including laryngeal edema,
can occur at any time with treatment with ACE inhibitors. Patients should be so
advised and told to report immediately any signs or symptoms suggesting
angioedema (swelling of face, eyes, lips, or tongue, or difficulty in breathing)
and to take no more drug until they have consulted with the prescribing
physician.
Symptomatic Hypotension: Patients should be cautioned
that lightheadedness can occur, especially during the first days of therapy, and
it should be reported to the prescribing physician. Patients should be told that
if syncope occurs, benazepril hydrochloride should be discontinued until the
prescribing physician has been consulted.
All patients should be cautioned that inadequate fluid intake or excessive
perspiration, diarrhea, or vomiting can lead to an excessive fall in blood
pressure, with the same consequences of lightheadedness and possible
syncope.
Hyperkalemia: Patients should be told not to use
potassium supplements or salt substitutes containing potassium without
consulting the prescribing physician.
Neutropenia: Patients should be told to promptly
report any indication of infection (e.g., sore throat, fever), which could be a
sign of neutropenia.
Drug Interactions Diuretics: Patients on diuretics,
especially those in whom diuretic therapy was recently instituted, may
occasionally experience an excessive reduction of blood pressure after
initiation of therapy with benazepril hydrochloride. The possibility of
hypotensive effects with benazepril hydrochloride can be minimized by either
discontinuing the diuretic or increasing the salt intake prior to initiation of
treatment with benazepril hydrochloride. If this is not possible, the starting
dose should be reduced (see DOSAGE AND ADMINISTRATION).
Potassium Supplements and Potassium-Sparing
Diuretics: Benazepril hydrochloride can attenuate potassium loss caused
by thiazide diuretics. Potassium-sparing diuretics (spironolactone, amiloride,
triamterene, and others) or potassium supplements can increase the risk of
hyperkalemia. Therefore, if concomitant use of such agents is indicated, they
should be given with caution, and the patient’s serum potassium should be
monitored frequently.
Oral Anticoagulants: Interaction studies with
warfarin and acenocoumarol failed to identify any clinically important effects
on the serum concentrations or clinical effects of these anticoagulants.
Lithium: Increased serum lithium levels and symptoms
of lithium toxicity have been reported in patients receiving ACE inhibitors
during therapy with lithium. These drugs should be coadministered with caution,
and frequent monitoring of serum lithium levels is recommended. If a diuretic is
also used, the risk of lithium toxicity may be increased.
Gold: Nitritoid reactions (symptoms include facial
flushing, nausea, vomiting and hypotension) have been reported rarely in
patients on therapy with injectable gold (sodium aurothiomalate) and concomitant
ACE inhibitor therapy.
Anti-diabetics: In rare cases, diabetic patients
receiving an ACE inhibitor (including benazepril) concomitantly with insulin or
oral anti-diabetics may develop hypoglycemia. Such patients should therefore be
advised about the possibility of hypoglycemic reactions and should be monitored
accordingly.
Other: No clinically important pharmacokinetic
interactions occurred when Benazepril hydrochloride was administered
concomitantly with hydrochlorothiazide, chlorthalidone, furosemide, digoxin,
propranolol, atenolol, naproxen, or cimetidine.
Benazepril hydrochloride has been used concomitantly with
beta-adrenergic-blocking agents, calcium-channel-blocking agents, diuretics,
digoxin, and hydralazine, without evidence of clinically important adverse
interactions. Benazepril, like other ACE inhibitors, has had less than additive
effects with beta-adrenergic blockers, presumably because both drugs lower blood
pressure by inhibiting parts of the renin-angiotensin system.
Carcinogenesis, Mutagenesis, Impairment of Fertility
No evidence of carcinogenicity was found when benazepril was administered to
rats and mice for up to two years at doses of up to 150 mg/kg/day. When compared
on the basis of body weights, this dose is 110 times the maximum recommended
human dose. When compared on the basis of body surface areas, this dose is 18
and 9 times (rats and mice, respectively) the maximum recommended human dose
(calculations assume a patient weight of 60 kg). No mutagenic activity was
detected in the Ames test in bacteria (with or without metabolic activation), in
an in vitro test for forward mutations in cultured mammalian cells, or in a
nucleus anomaly test. In doses of 50-500 mg/kg/day (6-60 times the maximum
recommended human dose based on mg/m2 comparison and
37-375 times the maximum recommended human dose based on a mg/kg comparison),
Benazepril hydrochloride had no adverse effect on the reproductive performance
of male and female rats.
Nursing Mothers Minimal amounts of unchanged benazepril and of benazeprilat are
excreted into the breast milk of lactating women treated with benazepril. A
newborn child ingesting entirely breast milk would receive less than 0.1% of the
mg/kg maternal dose of benazepril and benazeprilat.
Geriatric Use Of the total number of patients who received benazepril in U.S.
clinical studies of Benazepril hydrochloride, 18% were 65 or older while 2% were
75 or older. No overall differences in effectiveness or safety were observed
between these patients and younger patients, and other reported clinical
experience has not identified differences in responses between the elderly and
younger patients, but greater sensitivity of some older individuals cannot be
ruled out.
Benazepril and benazeprilat are substantially excreted by the kidney. Because
elderly patients are more likely to have decreased renal function, care should
be taken in dose selection, and it may be useful to monitor renal function.
Pediatric
Use
The antihypertensive effects of Benazepril hydrochloride have been evaluated
in a double-blind study in pediatric patients 7 to 16 years of age (see CLINICAL PHARMACOLOGY:
Pharmacodynamics, Hypertension). The pharmacokinetics of Benazepril
hydrochloride have been evaluated in pediatric patients 6 to 16 years of age
(see CLINICAL PHARMACOLOGY:
Pharmacokinetics and Metabolism). Benazepril hydrochloride was generally
well tolerated and adverse effects were similar to those described in adults.
(See ADVERSE REACTIONS:
Pediatric Patients).
Treatment with Benazepril hydrochloride is not recommended in pediatric
patients less than 6 years of age (see ADVERSE REACTIONS), and in
children with glomerular filtration rat less than 30 mL/min as there are insufficient
data available to support a dosing recommendation in these groups. (See CLINICAL PHARMACOLOGY: In Pediatric
Patients and DOSAGE AND
ADMINISTRATION.)