Chemical formula: C₂₄H₂₈N₂O₅ Molecular mass: 424.49 g/mol PubChem compound: 5362124
Benazepril interacts in the following cases:
In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs, including selective COX-2 inhibitors, with ACE inhibitors, including benazepril, may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving benazepril and NSAID therapy.
The antihypertensive effect of ACE inhibitors, including benazepril, may be attenuated by NSAIDs.
Monitor renal function periodically in patients treated with benazepril. Changes in renal function, including acute renal failure, can be caused by drugs that inhibit the renin-angiotensin system.
Patients whose renal function may depend on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, chronic kidney disease, severe congestive heart failure, post-myocardial infarction, or volume depletion) may be at particular risk of developing acute renal failure on benazepril. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on benazepril.
For adults with a GFR <30 mL/min/1.73 m² (serum creatinine >3 mg/dL), the recommended initial dose is 5 mg benazepril once daily. Dosage may be titrated upward until blood pressure is controlled or to a maximum total daily dose of 40 mg. Benazepril can also worsen renal function.
Concomitant administration of benazepril and antidiabetic medicines (insulins, oral hypoglycemic agents) may increase the risk of hypoglycemia.
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. The possibility of hypotensive effects with benazepril can be minimized by either discontinuing or decreasing the dose of diuretic prior to initiation of treatment with benazepril.
Potassium-sparing diuretics (spironolactone, amiloride, triamterene, and others) can increase the risk of hyperkalemia. Therefore, if concomitant use of such agents is indicated, monitor the patient’s serum potassium frequently. Benazepril attenuates potassium loss caused by thiazide-type diuretics.
Patients receiving coadministration of ACE inhibitor and mTOR inhibitor (e.g., temsirolimus, sirolimus, everolimus) therapy may be at increased risk for angioedema. Monitor for signs of angioedema.
Lithium toxicity has been reported in patients receiving lithium concomitantly with benazepril. Lithium toxicity was usually reversible upon discontinuation of lithium or benazepril. Monitor serum lithium levels during concurrent use.
Benazepril can cause symptomatic hypotension, sometimes complicated by oliguria, progressive azotemia, acute renal failure, or death. Patients at risk of excessive hypotension include those with the following conditions or characteristics: heart failure with systolic blood pressure below 100 mmHg, ischemic heart disease, cerebrovascular disease, hyponatremia, high dose diuretic therapy, renal dialysis, or severe volume and/or salt depletion of any etiology.
In such patients, follow closely for the first 2 weeks of treatment and whenever the dose of benazepril or diuretic is increased. Avoid use of benazepril in patients who are hemodynamically unstable after acute MI.
Serum potassium should be monitored periodically in patients receiving benazepril. Drugs that inhibit the renin-angiotensin system can cause hyperkalemia. 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.
Two patients undergoing desensitizing treatment with hymenoptera venom while receiving ACE inhibitors sustained life-threatening anaphylactoid reactions.
Sudden and potentially life threatening anaphylactoid reactions have occurred in some patients dialyzed with high-flux membranes and treated concomitantly with an ACE inhibitor. In such patients, dialysis must be stopped immediately, and aggressive therapy for anaphylactoid reactions must be initiated. Symptoms have not been relieved by antihistamines in these situations. In these patients, consideration should be given to using a different type of dialysis membrane or a different class of antihypertensive agent. Anaphylactoid reactions have also been reported in patients undergoing low-density lipoprotein apheresis with dextran sulfate absorption.
ACE inhibitors have been associated with a syndrome that starts with cholestatic jaundice and progresses to fulminant hepatic necrosis and (sometimes) death. The mechanism of this syndrome is not understood. Patients receiving ACE inhibitors who develop jaundice or marked elevations of hepatic enzymes should discontinue the ACE inhibitor and receive appropriate medical follow-up.
Angioedema of the face, extremities, lips, tongue, glottis, and/or larynx including some fatal reactions, have occured in patients treated with benazepril. Patients with involvement of the tongue, glottis or larynx are likely to experience airway obstruction, especially those with a history of airway surgery. Benazepril should be promptly discontinued and appropriate therapy and monitoring should be provided until complete and sustained resolution of signs and symptoms of angioedema has occurred.
Patients with a history of angioedema unrelated to ACE inhibitor therapy may be at increased risk of angioedema while receiving an ACE inhibitor. ACE inhibitors have been associated with a higher rate of angioedema in Black than in non-Black patients.
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.
Intestinal angioedema has occurred 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. In some cases, the angioedema was diagnosed by procedures including abdominal CT scan or ultrasound, or at surgery, and symptoms resolved after stopping the ACE inhibitor.
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.
Benazepril can cause fetal harm when administered to a pregnant woman. Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the renin angiotensin system from other antihypertensive agents. When pregnancy is detected, discontinue benazepril as soon as possible.
The estimated background risk of major birth defects and miscarriage for the indicated population are unknown. All pregnancies have a background risk of birth defects, loss, or other adverse outcomes. In the general U.S. population, the estimated background risk of major defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.
Hypertension in pregnancy increases the maternal rush for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section, and post-partum hemorrhage). Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death. Pregnant women with hypertension should be carefully monitored and managed accordingly.
Oligohydramnios in pregnant women who use drugs affecting the renin-angiotensin system in the second and third trimesters of pregnancy can result in the following: reduced fetal renal function leading to anuria and renal failure, fetal lung hypoplasia and skeletal deformations, including skull hypoplasia, hypotension, and death. In the unusual case that there is no appropriate alternative to therapy with drugs affecting the renin-angiotensin system for a particular patient, apprise the mother of the potential risk to the fetus.
Perform serial ultrasound examinations to assess the intra-amniotic environment.
Fetal testing may be appropriate, based on the week of pregnancy. Patients and physicians should be aware, however, that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe infants with histories of in utero exposure to benazepril for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occur in neonates with a history of in utero exposure to benazepril, support blood pressure and renal perfusion. Exchange transfusions or dialysis may be required as a means of reversing hypotension and substituting for disordered renal function.
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.
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 to 500 mg/kg/day (6 to 60 times the maximum recommended human dose based on mg/m² comparison and 37 to 375 times the maximum recommended human dose based on a mg/kg comparison), benazepril had no adverse effect on the reproductive performance of male and female rats.
As with other antihypertensive drugs, it is advisable to exercise caution when driving or operating machines.
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.
Benazepril has been evaluated for safety in over 6000 patients with hypertension; over 700 of these patients were treated for at least one year. The overall incidence of reported adverse events was similar in benazepril and placebo patients.
The reported side effects were generally mild and transient, and there was no relation between side effects and age, duration of therapy, or total dosage within the range of 2 to 80 mg.
Discontinuation of therapy because of a side effect was required in approximately 5% of U.S. patients treated with benazepril and in 3% of patients treated with placebo. The most common reasons for discontinuation were headache (0.6%) and cough (0.5%).
Adverse reactions seen in at least 1% greater frequency in patients treated with benazepril than placebo were headache (6% vs. 4%), dizziness (4% vs. 2%), somnolence (2% vs. 0%) and postural dizziness (2% vs. 0%).
Adverse reactions reported in controlled clinical trials (less than 1% more on benazepril than on placebo), and rarer events seen in post-marketing experience, include the following (in some, a causal relationship to drug use is uncertain):
Dermatologic: Stevens-Johnson syndrome, pemphigus, apparent hypersensitivity reactions (manifested by dermatitis, pruritus, or rash), photosensitivity, and flushing.
Gastrointestinal: Nausea, pancreatitis, constipation, gastritis, vomiting, and melena.
Hematologic: Thrombocytopenia and hemolytic anemia.
Neurologic/Psychiatric: Anxiety, decreased libido, hypertonia, insomnia, nervousness, and paresthesia.
Other: Fatigue, asthma, bronchitis, dyspnea, sinusitis, urinary tract infection, frequent urination, infection, arthritis, impotence, alopecia, arthralgia, myalgia, asthenia, sweating.
Elevations of uric acid, blood glucose, serum bilirubin, and liver enzymes have been reported, as have incidents of hyponatremia, electrocardiographic changes, eosinophilia, and proteinuria.
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