Benazepril (Lotensin) Flashcards

Benazepril Overview

• Benazepril is classified as an ACE inhibitor and antihypertensive medication.
• Administered orally, it has specific dosing instructions based on condition severity and response.

Dosing Information

• For hypertension, the initial dose is 10 mg once daily, with maintenance doses ranging from 20 to 40 mg once daily or in two doses.
• Maximum daily dosage is 80 mg; diuretic therapy should be paused 2-3 days before starting benazepril.
• If a diuretic cannot be stopped, begin with 5 mg/day.

Dose Adjustments

• For patients with renal impairment (CrCl <30 mL/min), the initial dose is 5 mg once daily, with a maximum of 40 mg daily.

Contraindications

• History of angioedema, concurrent use with aliskiren in diabetic patients, and hypersensitivity to benazepril or other ACE inhibitors are contraindicated.

Adverse Effects

• Common effects include dizziness (3.6%), headache (6.2%), cough (1.2%), and fatigue (2.4%).
• Serious side effects include Stevens-Johnson syndrome, intestinal angioedema, agranulocytosis, nephrotoxicity, and angioedema, with severe reactions occurring at lower frequencies.

Black Box Warning

• Discontinue use immediately if pregnancy is detected due to potential fetal injury or death linked to drugs affecting the renin-angiotensin system.

Drug Interactions

• Increase in serum potassium with potassium-sparing drugs (e.g., spironolactone, amiloride) and certain supplements.
• Concurrent NSAIDs may cause renal failure, especially in older patients or those with impaired kidney function.
• Lithium levels can rise to toxic levels when combined with benazepril.
• Alcohol should be avoided as it can enhance side effects.

Pregnancy Category

• Rated as Category D, indicating potential risk to the fetus.

Monitoring Requirements

• Assess reduction in blood pressure for efficacy and perform renal function tests initially, especially in vulnerable patients.
• During pregnancy, serial ultrasound examinations and fetal monitoring may be necessary.

Mechanism of Action

• Benazepril, as a prodrug, converts to benazeprilat which inhibits ACE, reducing angiotensin II levels leading to vasodilation, decreased blood pressure, and increased potassium levels through renin-angiotensin-aldosterone system suppression.

Pharmacokinetics

• Oral benazepril reaches peak concentration between 0.5 to 1 hour, with a bioavailability of at least 37%.
• Food does not significantly affect benazepril absorption, while it increases the Cmax of the active metabolite, benazeprilat, which peaks at 1-2 hours.
• Benazepril and its active form are highly protein-bound (approximately 96.7% and 95.3%).
• Benazepril is metabolized in the liver and primarily excreted through the kidneys as glucuronide conjugates. Benazeprilat is also renally excreted, with a notable amount remaining unchanged.