Detailed Drug Information:

DRUG CLASS AND MECHANISM: Quinapril belongs in a class of drugs called angiotensin converting enzyme (ACE) inhibitors. ACE inhibitors are used for treating high blood pressure and heart failure and for preventing kidney failure due to hypertension and diabetes. Other drugs in this class are enalapril (Vasotec), ramipril (Altace), captopril (Capoten), fosinopril (Monopril), benazepril (Lotensin), lisinopril (Zestril, Prinivil), moexipril (Univasc) and trandolapril (Mavik). Angiotensin converting enzyme is important because it produces angiotensin II. Angiotensin II contracts the muscles of the arteries in the heart and the rest of the body, narrowing the arteries and thereby elevating blood pressure. In the kidney, the narrowing caused by angiotensin II decreases blood flow and increases the filtration pressure in the kidney. ACE inhibitors such as quinapril lower blood pressure by inhibiting the formation of angiotensin II, thereby relaxing the arterial muscles and enlarging the arteries. This increases the flow of blood and oxygen to the heart so that it can pump blood more efficiently. The enlargement of the arteries elsewhere in the body also makes it easier for the heart to pump blood. This is particularly beneficial when there is heart failure. In the kidneys this increases blood flow and reduces the filtration pressure in the kidneys. Quinapril was approved by the FDA in November, 1991.

PREPARATIONS: Tablets: 5, 10, 20 and 40 mg

STORAGE:Store tablets and solutions at room temperature 15-30°C (59-86°F).

PRESCRIBED FOR: Quinapril is used alone or in combination with other drugs to treat hypertension and heart failure. As with other ACE inhibitors, quinapril also is used to delay the progression of kidney failure in patients with diabetes.

DOSING: The recommended dose for treating hypertension is 10-80 mg a day as a single dose or in two doses. The dose for heart failure is 20-40 mg a day in two divided doses. Quinapril should be taken on an empty stomach because food reduces its absorption.

DRUG INTERACTIONS: The use of ACE inhibitors with potassium supplements, salt substitutes or diuretics (e.g., spironolactone) that increase potassium in the blood may lead to excessive potassium levels. Potassium levels should be closely monitored whenever ace inhibitors are use in combination with these drugs.

There have been reports of increased lithium (Eskalith) levels when lithium is used in combination with ace inhibitors. The reason for this interaction is not known.

PREGNANCY: Angiotensin converting enzyme inhibitors, including quinapril, are very harmful to the fetus and, therefore, should not be used during pregnancy.

NURSING MOTHERS: Quinapril is secreted into breast milk. Because of the risk of harm to the infant, quinapril should be used with caution during breast feeding.

SIDE EFFECTS: Quinapril is generally well tolerated, and side effects are usually mild and transient. A dry, persistent cough has been reported with the use of quinapril and other ACE inhibitors. Coughing resolves after discontinuing the medication. Other side effects include abdominal pain, constipation, diarrhea, rash, dizziness, fatigue, headache, loss of taste, loss of appetite, nausea, vomiting, fainting and numbness or tingling in the hands or feet. Quinapril and other ACE inhibitors may also cause kidney failure and increased levels of potassium in the blood. The most serious but very rare side effects are liver failure and angioedema (swelling of lips and throat).