LOTENSIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LOTENSIN (LOTENSIN).
Benazepril is an angiotensin-converting enzyme (ACE) inhibitor that blocks the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This leads to decreased vasopressor activity, aldosterone secretion, and increased plasma renin activity.
| Metabolism | Hepatic via glucuronidation and ester hydrolysis; primarily metabolized to benazeprilat, its active metabolite. CYP enzymes are minimally involved. |
| Excretion | Renal: ~60% unchanged in urine; Biliary/fecal: ~20% as metabolites; Total renal elimination: ~80-85% (parent drug + metabolites). |
| Half-life | Terminal elimination half-life: 12-13 hours for benazeprilat; 0.6 hours for benazepril. Clinical context: Half-life supports once-daily dosing, extending to 22-27 hours in severe renal impairment (CrCl <30 mL/min) requiring dose adjustment. |
| Protein binding | Benazeprilat: 90-93% primarily to serum albumin; Benazepril: ~96.7% bound. |
| Volume of Distribution | Benazeprilat: 0.15-0.2 L/kg; Benazepril: 0.7 L/kg. Clinical meaning: Low Vd for active metabolite indicates limited tissue distribution, predominantly in extracellular fluid. |
| Bioavailability | Oral: Benazepril ~37% (parent drug); Rapidly converted to active metabolite benazeprilat (bioavailability as ACE inhibitor ~13-18% due to extensive first-pass metabolism). |
| Onset of Action | Oral: 1 hour (therapeutic effect onset for blood pressure reduction); Maximum effect: 2-4 hours after dose. |
| Duration of Action | Duration: 24 hours (allows once-daily dosing). Clinical notes: Antihypertensive effect maintained over full dosing interval, with trough-to-peak ratio >0.5. |
10-40 mg orally once daily; initial dose 10 mg once daily; maximum 80 mg/day.
| Dosage form | TABLET |
| Renal impairment | GFR 30-60 mL/min: initial dose 5 mg once daily; GFR <30 mL/min: initial dose 2.5 mg once daily; titrate cautiously. |
| Liver impairment | Child-Pugh Class A: 5 mg once daily; Class B-C: not recommended (insufficient data). |
| Pediatric use | Weight ≥50 kg: same as adult; <50 kg: 0.07 mg/kg (max 5 mg) once daily initially; maximum 0.6 mg/kg/day (up to 40 mg/day). |
| Geriatric use | Initial dose 2.5-5 mg once daily; adjust based on renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LOTENSIN (LOTENSIN).
| Breastfeeding | Excreted in breast milk in low amounts; M/P ratio not established; risk of neonatal hypotension and renal dysfunction; avoid use in breastfeeding or use with caution. |
| Teratogenic Risk | First trimester: no increased risk of major congenital malformations; second and third trimesters: fetotoxicity (oligohydramnios, fetal renal dysfunction, skull ossification defects, hypotension, anuria, renal failure, death). |
| Fetal Monitoring |
■ FDA Black Box Warning
Fetal toxicity: Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus. Discontinue as soon as possible once pregnancy is detected.
| Serious Effects |
["History of angioedema related to previous ACE inhibitor therapy","Hypersensitivity to benazepril or any component of the formulation","Concomitant use with aliskiren in patients with diabetes mellitus or renal impairment (GFR <60 mL/min/1.73m²)"]
| Precautions | ["Anaphylactoid reactions including angioedema (higher risk in black patients)","Hypotension in volume-depleted patients","Renal impairment: monitor renal function","Hyperkalemia","Cough (common, non-productive)","Use in pregnancy: associated with oligohydramnios and fetal harm"] |
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| Monitor maternal blood pressure, renal function, serum potassium; fetal ultrasound for oligohydramnios and renal function; neonatal monitoring for hypotension, hyperkalemia, and oliguria. |
| Fertility Effects | No known direct effects on human fertility; animal studies show no impairment. |