SIDE EFFECTS
The following adverse reactions have been reported and
within each category (body system), are listed in order
of decreasing severity.
Digestive: Gastric bleeding, ulceration,
gastritis, diarrhea and cramping, nausea, vomiting.
Endocrine: Gynecomastia (see PRECAUTIONS),
inability to achieve or maintain erection, irregular menses
or amenorrhea, postmenopausal bleeding. Carcinoma of the
breast has been reported in patients taking spironolactone
but a cause and effect relationship has not been established.
Hematologic: Agranulocytosis.
Hypersensitivity: Fever, urticaria,
maculopapular or erythematous cutaneous eruptions, anaphylactic
reactions, vasculitis.
Nervous system/psychiatric: Mental confusion,
ataxia, headache, drowsiness, lethargy.
Liver/biliary: A very few cases of mixed
cholestatic/hepatocellular toxicity, with one reported
fatality, have been reported with spironolactone administration.
DRUG INTERACTIONS
ACE inhibitors: Concomitant administration
of ACE inhibitors with potassium-sparing diuretics has
been associated with severe hyperkalemia.
Alcohol, barbiturates, or narcotics:
Potentiation of orthostatic hypotension may occur.
Corticosteroids, ACTH: Intensified electrolyte
depletion, particularly hypokalemia, may occur.
Pressor amines (eg, norepinephrine):
Spironolactone reduces the vascular responsiveness to
norepinephrine. Therefore, caution should be exercised
in the management of patients subjected to regional or
general anesthesia while they are being treated with Aldactone.
Skeletal muscle relaxants, nondepolarizing (eg,
tubocurarine): Possible increased responsiveness
to the muscle relaxant may result.
Lithium: Lithium generally should not
be given with diuretics. Diuretic agents reduce the renal
clearance of lithium and add a high risk of lithium toxicity.
Nonsteroidal anti-inflammatory drugs (NSAIDs):
In some patients, the administration of an NSAID can reduce
the diuretic, natriuretic, and antihypertensive effect
of loop, potassium-sparing and thiazide diuretics. Combination
of NSAIDs, eg, indomethacin, with potassium-sparing diuretics
has been associated with severe hyperkalemia. Therefore,
when Aldactone and NSAIDs are used concomitantly, the
patient should be observed closely to determine if the
desired effect of the diuretic is obtained.
Digoxin: Spironolactone has been shown
to increase the half-life of digoxin. This may result
in increased serum digoxin levels and subsequent digitalis
toxicity. It may be necessary to reduce the maintenance
and digitalization doses when spironolactone is administered,
and the patient should be carefully monitored to avoid
over- or underdigitalization.
Drug/Laboratory Test Interactions
Several reports of possible interference with digoxin
radioimmunoassays by spironolactone, or its metabolites,
have appeared in the literature. Neither the extent nor
the potential clinical significance of its interference
(which may be assay-specific) has been fully established.
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