Quinapril

Drug Interactions Concomitant diuretic therapy As with other ACE inhibitors, patients on diuretics, especially those on recently instituted diuretic therapy, may occasionally experience an excessive reduction of blood pressure after initiation of therapy with quinapril hydrochloride. The possibility of hypotensive effects with quinapril hydrochloride may be minimized by either discontinuing the diuretic or cautiously increasing salt intake prior to initiation of treatment with quinapril hydrochloride. If it is not possible to discontinue the diuretic, the starting dose of quinapril should be reduced (see DOSAGE AND ADMINISTRATION ).

Agents increasing serum potassium Coadministration of quinapril hydrochloride with other drugs that raise serum potassium levels may result in hyperkalemia. Monitor serum potassium in such patients. Tetracycline and other drugs that interact with magnesium Simultaneous administration of tetracycline with quinapril hydrochloride reduced the absorption of tetracycline by approximately 28% to 37%, possibly due to the high magnesium content in quinapril tablets. This interaction should be considered if coprescribing quinapril hydrochloride and tetracycline or other drugs that interact with magnesium.

Lithium Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving concomitant lithium and ACE inhibitor therapy. These drugs should be coadministered with caution and frequent monitoring of serum lithium levels is recommended. If a diuretic is also used, it may increase the risk of lithium toxicity. Gold Nitritoid reactions (symptoms include facial flushing, nausea, vomiting, and hypotension) have been reported rarely in patients on therapy with injectable gold (sodium aurothiomalate) and concomitant ACE inhibitor therapy.

Non-steroidal anti-inflammatory agents including selective cyclooxygenase-2 inhibitors (COX-2 inhibitors) In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, co-administration of NSAIDs, including selective COX-2 inhibitors, with ACE inhibitors, including quinapril, may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving quinapril and NSAID therapy. The antihypertensive effect of ACE inhibitors, including quinapril may be attenuated by NSAIDs.

Agents that inhibit mTOR or other drugs known to cause angioedema Patients taking concomitant mTOR inhibitor (e.g., temsirolimus) therapy or a neprilysin inhibitor may be at increased risk for angioedema. Other agents Drug interaction studies of quinapril hydrochloride with other agents showed: Multiple dose therapy with propranolol or cimetidine has no effect on the pharmacokinetics of single doses of quinapril hydrochloride. The anticoagulant effect of a single dose of warfarin (measured by prothrombin time) was not significantly changed by quinapril coadministration twice-daily. Quinapril hydrochloride treatment did not affect the pharmacokinetics of digoxin.

No pharmacokinetic interaction was observed when single doses of quinapril hydrochloride and hydrochlorothiazide were administered concomitantly. Co-administration of multiple 10 mg doses of atorvastatin with 80 mg of quinapril hydrochloride resulted in no significant change in the steady-state pharmacokinetic parameters of atorvastatin. Dual Blockade of the Renin-Angiotensin System (RAS) Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy.

Most patients receiving the combination of two RAS inhibitors do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAS inhibitors. Closely monitor blood pressure, renal function and electrolytes in patients on quinapril hydrochloride and other agents that affect the RAS. Do not co-administer aliskiren with quinapril hydrochloride in patients with diabetes. Avoid concomitant use of aliskiren with quinapril hydrochloride in patients with renal impairment (GFR<60 mL/min/1.73 m 2 ).

Pregnancy Tell female patients of childbearing age about the consequences of exposure to quinapril hydrochloride during pregnancy. Discuss treatment options with women planning to become pregnant. Ask patients to report pregnancies to their physicians as soon as possible. Angioedema Angioedema, including laryngeal edema can occur with treatment with ACE inhibitors, especially following the first dose. Advise patients and tell them to immediately report any signs or symptoms suggesting angioedema (swelling of face, extremities, eyes, lips, tongue, difficulty in swallowing or breathing) and to stop taking the drug until they have consulted with their physician (see WARNINGS ).

Symptomatic hypotension Caution patients that lightheadedness can occur, especially during the first few days of quinapril hydrochloride therapy, and that it should be reported to a physician. If actual syncope occurs, tell patients to temporarily discontinue the drug until they have consulted with their physician (see WARNINGS ). Caution all patients that inadequate fluid intake or excessive perspiration, diarrhea, or vomiting can lead to an excessive fall in blood pressure because of reduction in fluid volume, with the same consequences of lightheadedness and possible syncope.

Tell patients planning to undergo any surgery and/or anesthesia to inform their physician that they are taking an ACE inhibitor. Hyperkalemia Tell patients not to use potassium supplements or salt substitutes containing potassium without consulting their physician (see PRECAUTIONS ). Neutropenia Tell patients to promptly report any indication of infection (e.g., sore throat, fever) which could be a sign of neutropenia. NOTE: As with many other drugs, certain advice to patients being treated with quinapril hydrochloride is warranted. This information is intended to aid in the safe and effective use of this medication. It is not a disclosure of all possible adverse or intended effects.

Nursing Mothers Because quinapril hydrochloride is secreted in human milk, caution should be exercised when this drug is administered to a nursing woman.