Quinapril HCl

A to Z Drug Facts

 Action Competitively inhibits angiotensin I–converting enzyme, resulting in prevention of angiotensin I conversion to angiotensin II, a potent vasoconstrictor that also stimulates aldosterone release. Clinical consequences are decrease in BP, reduced sodium resorption, and potassium retention.

 Indications Treatment of hypertension; adjunctive therapy of CHF.

 Contraindications Hypersensitivity to ACE inhibitors.

 Route/Dosage

Hypertension

ADULTS: PO 10 or 20 mg qd initially; adjust dosage at intervals of ³ 2 weeks. Maintenance: 20, 40, or 80 mg/day as single dose or 2 equally divided doses. In presence of renal impairment, recommended initial dose varies based on creatinine clearance: > 60 ml/min = 10 mg; 30 to 60 ml/min = 5 mg; 10 to 30 ml/min = 2.5 mg. ELDERLY: PO 10 mg qd followed by titration to the optimal response.

CHF

ADULTS: PO 5 mg bid initially; may increase dose weekly for clinical control. In patients with heart failure and renal impairment, the recommended initial dose is 5 mg with Ccr > 30 ml/min or 2.5 mg with Ccr 10 to 30 ml/min. If well tolerated, it may be given the following day as a twice-daily regimen. In the absence of excessive hypotension or significant deterioration of renal function, the dose may be increased at weekly intervals based on clinical and hemodynamic response.

 Interactions

Allopurinol: Greater risk of hypersensitivity possible with coadministration. Antacids: Quinapril bioavailability may be decreased. Separate administration times by 1 to 2 hr. Capsaicin: Cough may be exacerbated. Digoxin: May cause increased digoxin levels. Diuretics: Increased risk of hypotension. Food: Food (especially fat) reduces bioavailability of quinapril. Indomethacin: May reduce hypotensive effects, especially in low renin or volume-dependent hypertensive patients. Lithium: May cause increased lithium levels and symptoms of lithium toxicity. Loop diuretics: Effects of loop diuretics may be decreased. Phenothiazines: Enhanced hypotensive effect. Potassium supplements and potassium-sparing diuretics: Hyperkalemia. Tetracycline: Decreased tetracycline absorption.

 Lab Test Interferences False elevation of liver enzymes, serum bilirubin, uric acid, and blood glucose may occur.

 Adverse Reactions

CV: Hypotension; orthostatic hypotension. CNS: Headache; dizziness; fatigue; nervousness. DERM: Pruritus. GI: Nausea; abdominal pain; vomiting; diarrhea. META: Hyperkalemia; hyponatremia. RESP: Cough; asthma; bronchospasm. OTHER: Hypersensitivity; angioedema.

 Precautions

Pregnancy: Category D (second, third trimester); Category C (first trimester). Avoid use in pregnant patients and discontinue drug as soon as pregnancy is detected; closely observe infants with histories of in utero exposure. Lactation: Undetermined. Children: Safety and efficacy not established. Elderly patients: May show higher peak blood levels of metabolite. Angioedema: May occur and is potentially fatal if laryngeal edema occurs. Use drug with extreme caution in patients with hereditary angioedema. Cough: Chronic cough may occur during treatment; more common in women. Hepatic impairment: Use drug with caution; dosage reduction may be necessary because of impaired metabolism. Hypotension/first-dose effect: Significant decreases in BP may occur after first dose, especially in severely salt- or volume-depleted patients (eg, patients on aggressive diuretic therapy) or in those with heart failure. Neutropenia and agranulocytosis: Have occurred rarely; risk appears greater with renal dysfunction, heart failure, or immunosuppression. Proteinuria: Has occurred with similar agents, especially with high doses or prior renal disease. Renal impairment: May further decrease renal function with elevations in BUN and serum creatinine because of decreased renal perfusion. Furthermore, dosage should be reduced to compensate for reduced drug elimination.

 Administration/Storage

• Give 1 hr before meals.
• Do not administer antacids within 1 to 2 hours of this medication.
• Dose is adjusted at 2-wk intervals based on BP response at trough (predose) and peak (2 to 6 hr after dose) blood levels.
• If possible, discontinue diuretic therapy and increase salt intake » 1 wk prior to quinapril initiation to prevent severe hypotension precipitated by first dose. If diuretic cannot be discontinued, initial dose must be decreased to 5 mg.
• Monitor patient closely for 2 hr after first dose and for next 2 wk for hypotension.
• Store in light-resistant container at room temperature.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Note liver and renal disease, CHF, and concurrent use of diuretics or dialysis.
• Obtain baseline renal function tests (serum BUN, protein, creatinine, and urine dipstick for protein) and hepatic function tests prior to therapy.
• Caution patient to change position slowly; assist with ambulation.
• Monitor BP and pulse frequently during initial dose and during therapy.
• Monitor for hyperkalemia in patients with impaired renal function or diabetes mellitus and patients receiving potassium supplementation or potassium-sparing diuretics.
• Monitor BUN, creatinine, and electrolytes during therapy. Expect potassium to increase and BUN and creatinine to transiently increase; sodium may decrease.
• Monitor for lightheadedness, dizziness, and fainting. Provide for safety during first few days of therapy.
• Monitor renal function. Reduced dose is necessary in patients with renal impairment.
• Monitor WBC counts frequently.
• If severe hypotension occurs after first dose, if not medically contraindicated, administer IV infusion of normal saline (0.9% Sodium Chloride) as ordered as volume expander.
• If sudden severe dyspnea, swelling of lips or eyes, or edema of hands and feet develops, withhold medication and notify health care provider.

 Patient/Family Education

• Remind patient that quinapril controls, not cures, high BP.
• Emphasize importance of other BP-controlling activities (weight loss, regular exercise, smoking cessation, moderate alcohol intake, stress management).
• Teach patient/family proper BP measurement technique. If possible, have patient/family demonstrate use of monitor they will be using at home. Stress that BP should be checked weekly (at least) and that patient should report significant changes to health care provider immediately.
• Advise patient to report persistent dry, nonproductive cough. Remind patient not to self-medicate cough with otc medications unless instructed to do so by health care provider.
• Emphasize need for ongoing medical follow up, even in absence of side effects or problems related to this medication therapy.
• Advise CHF patient to avoid rapid increases in physical activity. Emphasize importance of adequate fluid intake.
• Warn patient that excessive perspiration, dehydration, vomiting, and diarrhea may lead to fall in BP.
• Caution patient not to use salt substitute containing potassium without consulting health care provider.
• Instruct patient to report these symptoms to health care provider immediately: Rash, mouth sores, taste impairment, fever, sore throat, swelling of face or mouth, swelling, numbness or tingling of hands or feet, chest pain, breathing difficulty, or jaundice.
• Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
• Advise patients taking diuretics that they may experience symptomatic hypotension following the initial dose of quinapril. To reduce the likelihood of this effect, discontinue the diuretic 2 to 3 days prior to quinapril therapy if possible.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts