DOSAGE AND ADMINISTRATION
Benazepril is an effective treatment of hypertension in once-daily doses of 10-80 mg, while hydrochlorothiazide is effective in doses of 12.5-50 mg per day. In clinical trials of benazepril/hydrochlorothiazide combination therapy using benazepril doses of 5-20 mg and hydrochlorothiazide doses of 6.25-25 mg, the antihypertensive effects increased with increasing dose of either component.
The side effects (see WARNINGS) of benazepril are generally rare and apparently independent of dose; those of hydrochlorothiazide are a mixture of dose-dependent phenomena (primarily hypokalemia) and dose-independent phenomena (e.g., pancreatitis), the former much more common than the latter. Therapy with any combination of benazepril and hydrochlorothiazide will be associated with both sets of dose-independent side effects, but regimens in which benazepril is combined with low doses of hydrochlorothiazide produce minimal effects on serum potassium. In clinical trials of Lotensin HCT, the average change in serum potassium was near zero in subjects who received 5/6.25 mg or 20/12.5 mg, but the average subject who received 10/12.5 mg or 20/25 mg experienced a mild reduction in serum potassium, similar to that experienced by the average subject receiving the same dose of hydrochlorothiazide monotherapy.
To minimize dose-independent side effects, it is usually appropriate to begin combination therapy only after a patient has failed to achieve the desired effect with monotherapy.
Dose Titration Guided by Clinical Effect: A patient whose blood pressure is not adequately controlled with benazepril monotherapy may be switched to Lotensin HCT 10/12.5 or Lotensin HCT 20/12.5. Further increases of either or both components could depend on clinical response. The hydrochlorothiazide dose should generally not be increased until 2-3 weeks have elapsed. Patients whose blood pressures are adequately controlled with 25 mg of daily hydrochlorothiazide, but who experience significant potassium loss with this regimen, may achieve similar blood-pressure control without electrolyte disturbance if they are switched to Lotensin HCT 5/6.25.
Replacement Therapy: The combination may be substituted for the titrated individual components.
Use in Renal Impairment: Regimens of therapy with Lotensin HCT need not take account of renal function as long as the patient’s creatinine clearance is >30 mL/min/1.73m2 (serum creatinine roughly ≤3 mg/dL or 265 µmol/L). In patients with more severe renal impairment, loop diuretics are preferred to thiazides, so Lotensin HCT is not recommended (see WARNINGS).
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