(For veterinary information only)
The size of the tablet/medication is NOT an indication of a proper dose. Never administer any drug without your veterinarian's input. Serious side effects or death can occur if you use drugs on your pet without your veterinarian's advice.
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Brand Name: Lotensin, Fortekor, Cardalis (combined with spironolactone)
Available in 5 mg, 10 mg, 20 mg, and 40 mg tablets
Heart Failure Management
Benazepril is used in two situations: managing heart failure and kidney protein loss. It may seem strange that one medication could have important effects on two separate organ systems like this, but in fact, the heart and kidney have a special relationship when it comes to blood pressure and circulation, and this is where benazepril fits in. It is an angiotensin converting enzyme inhibitor, more commonly known as an ACE Inhibitor or simply as an ACEI. It works to dilate (get bigger) blood vessels in the body. When blood vessels dilate, the blood pressure within will drop. This pressure drop is good if you want to lower abnormally high blood pressure, but it turns out other medications may be more effective for that purpose. The real benefit to dropping pressure in those blood vessels is that the heart does not have to work as hard when pumping against lower pressure there. Less work is important when the heart is weak and cannot handle its normal load.
Kidney (Renal) Protein Loss
The kidney's main job is to sort out which blood chemicals need to be dumped and which need to be kept. One thing for sure is that protein should always be kept. Protein is an important resource, and it is not easy to make. To be sure protein is kept in the body and not lost in urine with the waste chemicals being dumped, filtration membranes keep protein in. The problem is that certain diseases damage these membranes and protein is urinated away. Losing too much protein or just too much of an important protein can be disastrous. Fortunately, ACE Inhibitors help with this by lowering blood pressure within the kidney's filtration units. The result is less protein loss in urine.
This drawing of a nephron shows a glomerulus and blood vessels (graphic by MarVistaVet).
How this Medication is Used
Benazepril is used to treat congestive heart failure and kidney protein-loss (such as glomerulonephritis). Benazepril is removed from the body through both the liver and the kidneys. In patients with poor kidney function, it is frequently chosen over another ACEI called enalapril that removes it only from the kidneys. In other words, using benazapril instead allows the liver to take over some of the work from the kidney to remove the drug.
In heart failure patients, when benazepril is commonly given with a diuretic, such as furosemide or spironolactone, kidney parameters (BUN and creatinine) should be measured before using benazepril. They should be measured again 3-7 days after starting benazepril and periodically thereafter.
Kidney function should also be rechecked after any dose change in the heart failure patient.
Benazepril may be given with or without food and is usually given once a day. If a dose is accidentally skipped, do not double up on the next dose; simply pick up with the next dose when it is remembered.
Nausea, appetite loss, or diarrhea are sometimes seen with this medication. In these situations, the problem is often solved by giving it with food; however, in some patients, these effects are severe enough to stop using benazepril.
In some patients, blood pressure can drop too low as the peripheral blood vessels are dilated. This manifests as listlessness and lethargy. Often the dose of benazepril can be modified should this side effect occur.
Benazepril may lead to elevations in potassium blood levels.
Interactions with other Drugs
Benazepril is commonly used in combination with diuretics, especially furosemide. In this situation, monitoring kidney parameters is important as both of these medications serve to decrease blood supply to the kidney as they support the heart. Should a heart failure crisis occur while a patient is on these two medications, it will become necessary to rely on the diuretic to resolve the crisis. High doses of diuretic are typically needed. This can potentially lead to kidney failure although there is no alternative when the heart is failing.
Blood potassium levels can become dangerously high when benazepril is used with other medications that elevate blood potassium level. Such drugs might include: potassium supplements (Polycitra, or Urocit-K) or spironolactone (a potassium-sparing diuretic.)
Benazepril is less effective when used with aspirin or other NSAIDs. Concurrent use of benazepril and NSAIDs can increase the potential for kidney toxicity.
Benazepril may increase the risk of hypoglycemia (low blood sugar) when used concurrently with insulin or with oral hypoglycemic agents.
Concerns and Cautions
Benazepril is inactive when it is consumed and must be activated into benazeprilat (its active form) by the liver. If the patient’s liver is in failure and cannot reliably perform this conversion, an ACE inhibitor that does not require conversion can be used.
Benazepril probably should not be used in patients with impaired kidney function.
This medication should not be used in pregnancy or lactation.