Elevations of transaminases, LDH, alkaline phosphatase and serum bilirubin have been reported. In the majority of cases, the abnormalities were either present at baseline or were associated with other etiologic factors. In those cases which were possibly related to fosinopril therapy, the elevations were generally mild and transient and resolved after discontinuation of therapy. Patients on diuretics, especially those with intravascular volume depletion, may occasionally experience an excessive reduction of blood pressure after initiation of therapy with fosinopril sodium. The possibility of hypotensive effects can be minimized by either discontinuing the diuretic or increasing salt intake prior to initiation of treatment with fosinopril sodium.
Fosinopril sodium can attenuate potassium loss caused by thiazide diuretics.
Therefore, if concomitant use of such agents is indicated, they should be given with caution, and the patient's serum potassium should be monitored frequently. These drugs should be coadministered with caution, and frequent monitoring of serum lithium levels is recommended. If a diuretic is also used, the risk of lithium toxicity may be increased. Therefore, if concomitant administration of these agents is indicated, dosing should be separated by 2 hours. In separate single or multiple dose pharmacokinetic interaction studies with chlorthalidone, nifedipine, propanolol, hydrochlorothiazide, cimetidine, metoclopramide, propantheline, digoxin, and warfarin, the bioavailability of fosinoprilat was not altered by coadministration of fosinopril with any one of these drugs.