Single and multiple doses of 10 mg or more of benazepril cause inhibition of plasma ACE activity by at least 80% to 90% for at least 24 hours after dosing. For up to 4 hours after a 10 mg dose, pressor responses to exogenous angiotensin I were inhibited by 60% to 90%.
In normal human volunteers, single doses of benazepril caused an increase in renal blood flow but had no effect on glomerular filtration rate.
After oral administration of hydrochlorothiazide, diuresis begins within 2 hours, peaks in about 4 hours and lasts about 6 to 12 hours.
Benazepril hydrochloride and hydrochlorothiazide potentiates the antihypertensive action of other antihypertensive drugs (e.g., curare derivatives, guanethidine, methyldopa, beta-blockers, vasodilators, calcium channel blockers ACE inhibitors and ARBs and DRIs).
In single-dose studies, benazepril lowered blood pressure within 1 hour, with peak reductions achieved 2 to 4 hours after dosing. The antihypertensive effect of a single dose persisted for 24 hours. In multiple-dose studies, once-daily doses of 20 mg to 80 mg decreased seated pressure (systolic/diastolic) 24 hours after dosing by about 6-12/4-7 mmHg. The reductions at trough are about 50% of those seen at peak.
Four dose-response studies of benazepril monotherapy using once-daily dosing were conducted in 470 mild-to-moderate hypertensive patients not using diuretics. The minimal effective once-daily dose of benazepril was 10 mg; further falls in blood pressure, especially at morning trough, were seen with higher doses in the studied dosing range (10 mg to 80 mg). In studies comparing the same daily dose of benazepril given as a single morning dose or as a twice-daily dose, blood pressure reductions at the time of morning trough blood levels were greater with the divided regimen.
The antihypertensive effects of benazepril were not appreciably different in patients receiving high- or low-sodium diets.
In 15 controlled clinical trials, 1453 healthy or hypertensive patients were exposed to benazepril and hydrochlorothiazide of which 459 were exposed for at least 6 months, 214 for at least 12 months and 25 for at least 24 months.
The combination of benazepril-hydrochlorothiazide resulted in mean placebo-adjusted decreases in sitting systolic and diastolic blood pressures of 10/6 mm Hg with 5/6.25 mg and 10/12.5 mg doses, and 20/10 mmHg with 20/25 mg dose.
In clinical trials of benazepril/hydrochlorothiazide using benazepril doses of 5/20 mg and hydrochlorothiazide doses of 6.25/25 mg, the antihypertensive effects were sustained for at least 24 hours, and they increased with increasing dose of either component. Although benazepril monotherapy is somewhat less effective in blacks than in nonblacks, the efficacy of combination therapy appears to be independent of race.
Benazepril hydrochloride and hydrochlorothiazide tablets are indicated for the treatment of hypertension.
This fixed combination drug is not indicated for the initial therapy of hypertension (see DOSAGE AND ADMINISTRATION).
Benazepril hydrochloride and hydrochlorothiazide is contraindicated in patients who are anuric.
Benazepril hydrochloride and hydrochlorothiazide is also contraindicated in patients who are hypersensitive to benazepril, to any other ACE inhibitor, to hydrochlorothiazide, or to other sulfonamide-derived drugs. Hypersensitivity reactions are more likely to occur in patients with a history of allergy or bronchial asthma.
Benazepril hydrochloride and hydrochlorothiazide is also contraindicated in patients with a history of angioedema with or without previous ACE inhibitor treatment.
Benazepril hydrochloride and hydrochlorothiazide is contraindicated in combination with a neprilysin inhibitor (e.g., sacubitril). Do not administer benazepril hydrochloride and hydrochlorothiazide within 36 hours of switching to or from sacubitril/valsartan, a neprilysin inhibitor (see WARNINGS and PRECAUTIONS).
Do not coadminister aliskiren with angiotensin receptor blockers, ACE inhibitors, including benazepril hydrochloride and hydrochlorothiazide in patients with diabetes.
Presumably because angiotensin-converting enzyme inhibitors affect the metabolism of eicosanoids and polypeptides, including endogenous bradykinin, patients receiving ACE inhibitors (including benazepril) may be subject to a variety of adverse reactions, some of them serious.
Angioedema of the face, extremities, lips, tongue, glottis, and larynx has been reported in patients treated with angiotensin-converting enzyme inhibitors. In U.S. clinical trials, symptoms consistent with angioedema were seen in none of the subjects who received placebo and in about 0.5% of the subjects who received benazepril. Angioedema associated with laryngeal edema can be fatal. If laryngeal stridor or angioedema of the face, tongue, or glottis occurs, treatment with benazepril hydrochloride and hydrochlorothiazide should be discontinued and appropriate therapy instituted immediately. When involvement of the tongue, glottis, or larynx appears likely to cause airway obstruction, appropriate therapy, e.g., subcutaneous epinephrine injection 1:1000 (0.3 to 0.5 mL) should be promptly administered (see PRECAUTIONS and ADVERSE REACTIONS).
Black patients receiving ACE inhibitors have been reported to have a higher incidence of angioedema compared to nonblacks.
Patients receiving coadministration of ACE inhibitor and mTOR (mammalian target of rapamycin) inhibitor (e.g., temsirolimus, sirolimus, everolimus) therapy or a neprilysin inhibitor may be at increased risk for angioedema (see PRECAUTIONS).
Intestinal angioedema has been reported in patients treated with ACE inhibitors. These patients presented with abdominal pain (with or without nausea or vomiting); in some cases there was no prior history of facial angioedema and C-1 esterase levels were normal. The angioedema was diagnosed by procedures including abdominal CT scan or ultrasound, or at surgery, and symptoms resolved after stopping the ACE inhibitor. Intestinal angioedema should be included in the differential diagnosis of patients on ACE inhibitors presenting with abdominal pain.
Two patients undergoing desensitizing treatment with hymenoptera venom while receiving ACE inhibitors sustained life-threatening anaphylactoid reactions. In the same patients, these reactions were avoided when ACE inhibitors were temporarily withheld, but they reappeared upon inadvertent rechallenge.
Anaphylactoid reactions have been reported in patients dialyzed with high-flux membranes and treated concomitantly with an ACE inhibitor. Anaphylactoid reactions have also been reported in patients undergoing low-density lipoprotein apheresis with dextran sulfate absorption.
Hypersensitivity reactions to hydrochlorothiazide are more likely in patients with allergy and asthma.
Benazepril hydrochloride and hydrochlorothiazide can cause symptomatic hypotension. Like other ACE inhibitors, benazepril has been only rarely associated with hypotension in uncomplicated hypertensive patients. Symptomatic hypotension is most likely to occur in patients who have been volume and/or salt depleted as a result of prolonged diuretic therapy, dietary salt restriction, dialysis, diarrhea, or vomiting. Volume and/or salt depletion should be corrected before initiating therapy with benazepril hydrochloride and hydrochlorothiazide.
Benazepril hydrochloride and hydrochlorothiazide should be used cautiously in patients receiving concomitant therapy with other antihypertensives. The thiazide component of benazepril hydrochloride and hydrochlorothiazide may potentiate the action of other antihypertensive drugs, especially ganglionic or peripheral adrenergic-blocking drugs. The antihypertensive effects of the thiazide component may also be enhanced in the postsympathectomy patient.
In patients with congestive heart failure, with or without associated renal insufficiency, ACE inhibitor therapy may cause excessive hypotension, which may be associated with oliguria, azotemia, and (rarely) with acute renal failure and death. In such patients, benazepril hydrochloride and hydrochlorothiazide therapy should be started under close medical supervision; they should be followed closely for the first 2 weeks of treatment and whenever the dose of benazepril or diuretic is increased.
If hypotension occurs, the patient should be placed in a supine position, and, if necessary, treated with intravenous infusion of physiological saline. Benazepril hydrochloride and hydrochlorothiazide treatment usually can be continued following restoration of blood pressure and volume.
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