Benazepril

Mechanism :

Benazepril is an angiotensin converting enzyme (ACE) inhibitor which is used in the treatment of hypertension. Benazepril, after hydrolytic bioactivation to benazeprilat, inhibits angiotensin converting enzyme (ACE), a peptidyl dipeptidase catalysing the conversion of angiotensin I to the vasoconstrictor angiotensin II. Angiotensin II also stimulates aldosterone secretion by the adrenal cortex, leading to sodium resorption and potassium secretion by the distal renal tubules.

Indication :

• Mild to moderate essential hypertension

Contraindications :

In patients with known hypersensitivity to this product or any of its components and in patients with a history of angioedema related to previous treatment with an ACE inhibitor.

Dosing :

Adverse Effect :

Angioedema, hypotension, postural hypotension, syncope, headache, dizziness, fatigue, somnolence, postural dizziness, nausea and cough.

Interaction :

Concomitant Diuretic Therapy: Patients concomitantly taking ACE inhibitors and diuretics, may occasionally experience an excessive reduction of blood pressure after initiation of therapy. The possibility of hypotensive effects after the first dose of benazepril can be minimized by either discontinuing the diuretic or increasing the salt intake prior to initiation of treatment with benazepril. If it is not possible to discontinue the diuretic, the starting dose of benazepril should be reduced, and the patient should be closely observed for several hours following initial dose and until blood pressure has stabilized.
Agents Causing Renin Release: The antihypertensive effect of benazepril is augmented by antihypertensive agents that cause renin release (e.g., diuretics).
Agents Increasing Serum Potassium: Since benazepril decreases aldosterone production, increases of serum potassium may occur. Potassium sparing diuretics (e.g., spironolactone, triamterene, amiloride, etc.) or potassium supplements should be given only for documented hypokalemia and with caution and frequent monitoring of serum potassium, since they may lead to a significant increase in serum potassium.
Agents Affecting Sympathetic Activity: Agents affecting sympathetic activity (e.g., ganglionic blocking agents or adrenergic neuron blocking agents) may be used with caution. B-adrenergic blocking agents add some further antihypertensive effect to benazepril.
Indomethacin: Indomethacin may diminish the antihypertensive efficacy of concomitantly administered benazepril.
Lithium: Increased lithium levels and symptoms of lithium toxicity have been reported in patients receiving ACE inhibitors during therapy with lithium. These drugs should be coadministered with caution and frequent monitoring of serum lithium levels is recommended. If a diuretic is also used, the risk of lithium toxicity may be increased.
Hydrochlorothiazide, Chlorthalidone and Furosemide: The bioavailability of benazepril was not altered when single doses were administered concomitantly with the diuretic’s hydrochlorothiazide, chlorthalidone or furosemide.
ASA: No important changes in pharmacokinetic parameters occurred when single doses of benazepril were administered concomitantly with ASA.
Digoxin: In a single dose interaction study of benazepril with multiple doses of digoxin, no important changes in pharmacokinetic parameters were observed.
Amlodipine/Nifedipine: Benazepril has been used concomitantly with the calcium channel blockers amlodipine and nifedipine, without evidence of clinically important adverse interactions.
Other: In separate single or multiple dose pharmacokinetic interaction studies, the bioavailability of benazepril was not altered by coadministration with propranolol, naproxen, atenolol, nifedipine, amlodipine or cimetidine.

Hepatic Dose :