Quinapril and hydrochlorothiazide

Drug Interactions Agents Increasing Serum Potassium Coadministration of quinapril and hydrochlorothiazide with other drugs that raise serum potassium levels may result in hyperkalemia. Monitor serum potassium in such patients. Lithium Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving ACE inhibitors during therapy with lithium. Because renal clearance of lithium is reduced by thiazides, the risk of lithium toxicity is presumably raised further when, as in therapy with quinapril and hydrochlorothiazide, a thiazide diuretic is coadministered with the ACE inhibitor.

Quinapril and hydrochlorothiazide and lithium should be coadministered with caution, and frequent monitoring of serum lithium levels is recommended. 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 and hydrochlorothiazide and other agents that affect the RAS. Do not co-administer aliskiren with quinapril and hydrochlorothiazide in patients with diabetes. Avoid concomitant use of aliskiren with quinapril and hydrochlorothiazide in patients with renal impairment (GFR <60 mL/min/1.73 m 2 ). Tetracycline and Other Drugs That Interact with Magnesium Simultaneous administration of tetracycline with quinapril 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 and tetracycline or other drugs that interact with magnesium. 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 and other agents showed: Multiple dose therapy with propranolol or cimetidine has no effect on the pharmacokinetics of single doses of quinapril. The anticoagulant effect of a single dose of warfarin (measured by prothrombin time) was not significantly changed by quinapril coadministration twice daily. Digoxin: Thiazide-induced electrolyte disturbances, i.e.

hypokalemia, hypomagnesemia, increase the risk of digoxin toxicity, which may lead to fatal arrhythmic events (See PRECAUTIONS ). No pharmacokinetic interaction was observed when single doses of quinapril and hydrochlorothiazide were administered concomitantly. When administered concurrently, the following drugs may interact with thiazide diuretics. Alcohol, Barbiturates, or Narcotics—potentiation of orthostatic hypotension may occur. Antidiabetic Drugs (oral hypoglycemic agents and insulin)—dosage adjustments of the antidiabetic drug may be required (See PRECAUTIONS ).

Cholestyramine and Colestipol Resin—absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Single doses of either cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85% and 43%, respectively. Corticosteroids, ACTH—intensified electrolyte depletion, particularly hypokalemia. Pressor Amines (e.g., norepinephrine)—possible decreased response to pressor amines, but not sufficient to preclude their therapeutic use. Skeletal Muscle Relaxants, Nondepolarizing (e.g., tubocurarine)—possible increased responsiveness to the muscle relaxant.

Non-steroidal Anti-inflammatory Drugs—the diuretic, natriuretic, and antihypertensive effects of thiazide diuretics may be reduced by concurrent administration of nonsteroidal anti-inflammatory agents.

Pregnancy Tell female patients of childbearing age about the consequences of exposure to quinapril and hydrochlorothiazide during pregnancy. Discuss treatment options with women planning to become pregnant. Ask patients to report pregnancies to their physicians as soon as possible. Symptomatic Hypotension Tell patients receiving quinapril and hydrochlorothiazide that lightheadedness can occur, especially during the first days of therapy, and to report it to the prescribing physician. Tell the patient if syncope occurs, discontinue quinapril and hydrochlorothiazide until the physician has been consulted.

Tell patients that inadequate fluid intake, 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 major surgery and/ or general or spinal anesthesia to inform their physicians that they are taking an ACE inhibitor. Hyperkalemia Tell patients receiving quinapril and hydrochlorothiazide not to use potassium supplements or salt substitutes containing potassium without consulting the prescribing physician.

Neutropenia Tell patients to promptly report any indication of infection (e.g., sore throat, fever) which could be a sign of neutropenia. Non-melanoma Skin Cancer: Instruct patients taking hydrochlorothiazide to protect skin from the sun and undergo regular skin cancer screening. NOTE: As with many other drugs, certain advice to patients being treated with quinapril 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. Laboratory Tests The hydrochlorothiazide component of quinapril and hydrochlorothiazide may decrease serum PBI levels without signs of thyroid disturbance.

Therapy with quinapril and hydrochlorothiazide should be interrupted for a few days before carrying out tests of parathyroid function.

Nursing Mothers Because quinapril and hydrochlorothiazide are secreted in human milk, caution should be exercised when quinapril and hydrochlorothiazide is administered to a nursing woman. Because of the potential for serious adverse reactions in nursing infants from hydrochlorothiazide and the unknown effects of quinapril in infants, a decision should be made whether to discontinue nursing or to discontinue quinapril and hydrochlorothiazide, taking into account the importance of the drug to the mother.