(benazepril)
Brands
Fortekor (UK, Canada), Lotensin (USA)
Availability
- Scored Tablets: 5 mg, 10 mg, 20 mg
*Note: the 5 mg scored tablets can be easily divided to make two 2.5 mg tabs for giving to rats at their appropriate dosing. See the section on Dosage Recommendations.
Pharmacology
Benazepril hydrochloride is a second generation ACE (angiotensin-converting enzyme) inhibitor.
As an ACE inhibitor it has the ability to block an enzyme that enables the production of a substance which causes blood vessels to constrict. As a result, benazepril hydrochloride reduces vasoconstriction, decreases peripheral and pulmonary vascular resistance and right atrial pressure in the heart. This helps to lower blood pressure, as well as increase the supply of blood and oxygen to the heart.
Benazepril hydrochloride is distributed in the body more quickly than first generation ACE inhibitors. It does cross the placental barrier, but has not been shown to cause birth defects in animals when given in doses more than 3 times the highest recommended human dose.
Benazepril hydrochloride is metabolized in the liver to the active substance Benazeprilat. The drug is equally excreted by both liver and kidney (unlike older ACE inhibitors) reducing the need for dose modification, or monitoring of kidney function in the presence of renal disease. The drug is excreted in breast milk, and excreted unmetabolized in feces.
Indications
Used for treatment of heart failure (CHF), and dilated cardiomyopathy. May be a consideration for use, with caution, in PGN (progressive glomerulonephrosis) when hypertension is thought to be a factor (or to mitigate protein losing glomerulonephropathy 42) .
Drug Interactions or Contraindications
- Potential for increased hypotensive effects when used in conjunction with diuretics (e.g., Lasix) or other vasodilators (see Considerations).
- Use of NSAIDs with benazepril hydrochloride may reduce its efficacy.
Adverse Reactions
CV: hypotension; disturbances in heart rhythm
CNS: sleep disturbances, or lethargy
GI: diarrhea
Blood: neutropenia, agranulocytosis
Skin: pruritus (itching)
Dosage Recommendations
As a vasodilator and adjunctive therapy in heart failure, or in chronic kidney disease to reduce hypertension and decrease high levels of protein in urine:
0.5 mg/lb, or 1 mg/kg, PO, once or twice a day. The tablets are 2.5 mg, so a 1lb rat would be given
1/5th of a tablet. Starting at once a day, and increasing to twice a day as & when necessary (based on veterinary discretion to the rat’s response). 12
*Note: due to its dual excretion in liver and kidney this drug may be safer to use in older rats , or those rats with progressive glomerulonephropathy, than first generation ACE inhibitors.
or
Less than or equal to 0.1 mg/kg, PO, q24hr 34, 35
or
0.5 mg/kg to 1.0 mg/kg, PO, q24hr 41, 42, 44
*Note: at 0.5 mg/kg to 1.0 mg/kg, PO, q24hr may be used to mitigate protein loss in nephropathy. 42
Considerations
- May be used in combined treatment with a diuretic (e.g., Lasix) , digoxin, or antiarrhythmics as deemed appropriate by a veterinarian.
- Monitor weight. Report weight gain or increased edema (swelling).
- Avoid high sodium, high potassium foods
- Store in cool dry area and away from direct light.
