Hypertension 

Monotherapy: The recommended initial dosage of quinapril in patients not on diuretics is 10 or 20 mg once daily. Dosage should be adjusted according to blood pressure response measured at peak (2 to 6 hours after dosing) and trough (predosing). Generally, dosage adjustments should be made at intervals of at least 2 weeks. Most patients have required dosages of 20, 40, or 80 mg/day, given as a single dose or in two equally divided doses. In some patients treated once daily, the antihypertensive effect may diminish toward the end of the dosing interval. In such patients an increase in dosage or twice daily administration may be warranted. In general, doses of 40–80 mg and divided doses give a somewhat greater effect at the end of the dosing interval.

Concomitant Diuretics: If blood pressure is not adequately controlled with quinapril monotherapy, a diuretic may be added. In patients who are currently being treated with a diuretic, symptomatic hypotension occasionally can occur following the initial dose of quinapril. To reduce the likelihood of hypotension, the diuretic should, if possible, be discontinued 2 to 3 days prior to beginning therapy with quinapril (see WARNINGS). Then, if blood pressure is not controlled with quinapril alone, diuretic therapy should be resumed.

If the diuretic cannot be discontinued, an initial dose of 5 mg quinapril should be used with careful medical supervision for several hours and until blood pressure has stabilized.

The dosage should subsequently be titrated (as described above) to the optimal response (see WARNINGS, PRECAUTIONS, and Drug Interactions).

Renal Impairment: Kinetic data indicate that the apparent elimination half-life of quinaprilat increases as creatinine clearance decreases. Recommended starting doses, based on clinical and pharmacokinetic data from patients with renal impairment, are as follows:

Patients should subsequently have their dosage titrated (as described above) to the optimal response.

Elderly (≥65 years): The recommended initial dosage of quinapril in elderly patients is 10 mg given once daily followed by titration (as described above) to the optimal response.

Heart Failure 

Quinapril is indicated as adjunctive therapy when added to conventional therapy including diuretics and/or digitalis. The recommended starting dose is 5 mg twice daily. This dose may improve symptoms of heart failure, but increases in exercise duration have generally required higher doses. Therefore, if the initial dosage of quinapril is well tolerated, patients should then be titrated at weekly intervals until an effective dose, usually 20 to 40 mg daily given in two equally divided doses, is reached or undesirable hypotension, orthostatis, or azotemia (see WARNINGS) prohibit reaching this dose.

Following the initial dose of quinapril, the patient should be observed under medical supervision for at least two hours for the presence of hypotension or orthostatis and, if present, until blood pressure stabilizes. The appearance of hypotension, orthostatis, or azotemia early in dose titration should not preclude further careful dose titration. Consideration should be given to reducing the dose of concomitant diuretics.

DOSE ADJUSTMENTS IN PATIENTS WITH HEART FAILURE AND RENAL IMPAIRMENT OR HYPONATREMIA 

Pharmacokinetic data indicate that quinapril elimination is dependent on level of renal function. In patients with heart failure and renal impairment, the recommended initial dose of quinapril is 5 mg in patients with a creatinine clearance above 30 mL/min and 2.5 mg in patients with a creatinine clearance of 10 to 30 mL/min. There is insufficient data for dosage recommendation in patients with a creatinine clearance less than 10 mL/min (see DOSAGE AND ADMINISTRATION, Heart Failure, WARNINGS, and PRECAUTIONS, Drug Interactions).

If the initial dose is well tolerated, quinapril may be administered 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.