DOSAGE AND ADMINISTRATION
Captopril should be taken one hour before meals. Dosage must be individualized.
Hypertension
Initiation of therapy requires consideration of recent antihypertensive drug treatment, the extent of blood pressure elevation, salt restriction, and other clinical circumstances. If possible, discontinue the patient’s previous antihypertensive drug regimen for one week before starting captopril.
The initial dose of captopril is 25 mg b.i.d. or t.i.d. If satisfactory reduction of blood pressure has not been achieved after one or two weeks, the dose may be increased to 50 mg b.i.d. or t.i.d. Concomitant sodium restriction may be beneficial when captopril is used alone.
The dose of captopril in hypertension usually does not exceed 50 mg t.i.d. Therefore, if the blood pressure has not been satisfactorily controlled after one to two weeks at this dose, (and the patient is not already receiving a diuretic), a modest dose of a thiazide-type diuretic (e.g., hydrochlorothiazide, 25 mg daily), should be added. The diuretic dose may be increased at one- to two-week intervals until its highest usual antihypertensive dose is reached.
If captopril is being started in a patient already receiving a diuretic, captopril therapy should be initiated under close medical supervision (see WARNINGS and PRECAUTIONS: Drug Interactions regarding Hypotension ), with dosage and titration of captopril as noted above.
If further blood pressure reduction is required, the dose of captopril may be increased to 100 mg b.i.d. or t.i.d. and then, if necessary, to 150 mg b.i.d. or t.i.d. (while continuing the diuretic). The usual dose range is 25 to 150 mg b.i.d. or t.i.d. A maximum daily dose of 450 mg captopril should not be exceeded.
For patients with severe hypertension (e.g., accelerated or malignant hypertension), when temporary discontinuation of current antihypertensive therapy is not practical or desirable, or when prompt titration to more normotensive blood pressure levels is indicated, diuretic should be continued but other current antihypertensive medication stopped and captopril dosage promptly initiated at 25 mg b.i.d. or t.i.d., under close medical supervision.
When necessitated by the patient’s clinical condition, the daily dose of captopril may be increased every 24 hours or less under continuous medical supervision until a satisfactory blood pressure response is obtained or the maximum dose of captopril is reached. In this regimen, addition of a more potent diuretic, e.g., furosemide, may also be indicated.
Beta-blockers may also be used in conjunction with captopril therapy (see PRECAUTIONS: Drug Interactions), but the effects of the two drugs are less than additive.
Heart Failure
Initiation of therapy requires consideration of recent diuretic therapy and the possibility of severe salt/volume depletion. In patients with either normal or low blood pressure, who have been vigorously treated with diuretics and who may be hyponatremic and/or hypovolemic, a starting dose of 6.25 or 12.5 mg t.i.d. may minimize the magnitude or duration of the hypotensive effect (see WARNINGS Hypotension); for these patients, titration to the usual daily dosage can then occur within the next several days.
For most patients the usual initial daily dosage is 25 mg t.i.d. After a dose of 50 mg t.i.d. is reached, further increases in dosage should be delayed, where possible, for at least two weeks to determine if a satisfactory response occurs. Most patients studied have had a satisfactory clinical improvement at 50 or 100 mg t.i.d. A maximum daily dose of 450 mg of captopril should not be exceeded.
Captopril should generally be used in conjunction with a diuretic and digitalis. Captopril therapy must be initiated under very close medical supervision.
Left Ventricular Dysfunction After Myocardial Infarction
The recommended dose for long-term use in patients following a myocardial infarction is a target maintenance dose of 50 mg t.i.d.
Therapy may be initiated as early as three days following a myocardial infarction. After a single dose of 6.25 mg, captopril therapy should be initiated at 12.5 mg t.i.d. Captopril should then be increased to 25 mg t.i.d. during the next several days and to a target dose of 50 mg t.i.d. over the next several weeks as tolerated (see CLINICAL PHARMACOLOGY).
Captopril may be used in patients treated with other post-myocardial infarction therapies, e.g., thrombolytics, aspirin, beta blockers.
Dosage Adjustment in Renal Impairment
Because captopril is excreted primarily by the kidneys, excretion rates are reduced in patients with impaired renal function. These patients will take longer to reach steady-state captopril levels and will reach higher steady-state levels for a given daily dose than patients with normal renal function. Therefore, these patients may respond to smaller or less frequent doses.
Accordingly, for patients with significant renal impairment, initial daily dosage of captopril should be reduced, and smaller increments utilized for titration, which should be quite slow (one- to two-week intervals). After the desired therapeutic effect has been achieved, the dose should be slowly back-titrated to determine the minimal effective dose. When concomitant diuretic therapy is required, a loop diuretic (e.g., furosemide), rather than a thiazide diuretic, is preferred in patients with severe renal impairment. (See WARNINGS: Anaphylactoid Reactions During Membrane Exposure and PRECAUTIONS: Hemodialysis.)
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