Anaphylactoid and Possibly Related Reactions
Presumably because angiotensin-converting enzyme inhibitors affect the metabolism of eicosanoids and polypeptides, including endogenous bradykinin, patients receiving ACE inhibitors, including UNIVASC, may be subject to a variety of adverse reactions, some of them serious.
Angioedema: Angioedema involving the face, extremities, lips,
tongue, glottis, and/or larynx has been reported in patients treated with ACE
inhibitors, including UNIVASC. Symptoms suggestive of angioedema or facial edema
occurred in < 0.5% of moexipril-treated patients in placebo-controlled trials.
None of the cases were considered life-threatening and all resolved either without
treatment or with medication (antihistamines or glucocorticoids). One patient
treated with hydrochlorothiazide alone experienced laryngeal edema. No instances
of angioedema were reported in placebo-treated patients. In cases of angioedema,
treatment should be promptly discontinued and the patient carefully observed
until the swelling disappears.
In instances where swelling has been confined to the face and lips, the condition
has generally resolved without treatment, although antihistamines have been
useful in relieving symptoms.
Angioedema associated with involvement of the tongue, glottis, or larynx,
may be fatal due to airway obstruction. Appropriate therapy, e.g., subcutaneous
epi-nephrine solution 1:1000 (0.3 to 0.5 mL) and/or measures to ensure a patent airway, should be promptly provided (see ADVERSE REACTIONS).
Anaphylactoid Reactions During Desensitization: Two patients
undergoing desensitizing treatment with hymenoptera venom while receiving ACE
inhibitors sustained life-threatening anaphylactoid reactions. In the same patients,
these reactions did not occur when ACE inhibitors were temporarily withheld,
but they reappeared when the ACE inhibitors were inadvertently readministered.
Anaphylactoid Reactions During Membrane Exposure: Anaphylactoid
reactions have been reported in patients dialyzed with high-flux membranes and
treated concomitantly with an ACE inhibitor. Anaphylactoid reactions have also
been reported in patients undergoing low-density lipoprotein apheresis with
dextran sulfate absorption.
Hypotension
UNIVASC can cause symptomatic hypotension, although, as with other ACE inhibitors,
this is unusual in uncomplicated hypertensive patients treated with UNI-VASC
alone. Symptomatic hypotension was seen in 0.5% of patients given moex-ipril
and led to discontinuation of therapy in about 0.25%. Symptomatic hypoten-sion
is most likely to occur in patients who have been salt- and volume-depleted
as a result of prolonged diuretic therapy, dietary salt restriction, dialysis,
diarrhea, or vomiting. Volume- and salt-depletion should be corrected and, in
general, diuretics stopped, before initiating therapy with UNIVASC (see PRECAUTIONS:
DRUG INTERACTIONS, and ADVERSE
REACTIONS).
In patients with congestive heart failure, with or without associated renal
insufficiency, ACE inhibitor therapy may cause excessive hypotension, which
may be associated with oliguria or progressive azotemia, and rarely, with acute
renal failure and death. In these patients, UNIVASC therapy should be started
under close medical supervision, and patients should be followed closely for
the first two weeks of treatment and whenever the dose of moexipril or an accompanying
diuretic is increased. Care in avoiding hypotension should also be taken in
patients with ischemic heart disease, aortic stenosis, or cerebrovascular disease,
in whom an excessive decrease in blood pressure could result in a myocardial
infarction or a cerebrovascular accident.
If hypotension occurs, the patient should be placed in a supine position and,
if necessary, treated with an intravenous infusion of normal saline. UNIVASC
treatment usually can be continued following restoration of blood pressure and
volume.
Neutropenia/Agranulocytosis
Another ACE inhibitor, captopril, has been shown to cause agranulocytosis and
bone marrow depression, rarely in patients with uncomplicated hypertension,
but more frequently in hypertensive patients with renal impairment, especially
if they also have a collagen-vascular disease such as systemic lupus erythematosus
or scleroderma. Although there were no instances of severe neutropenia (absolute
neutrophil count < 500/mm3) among patients given UNIVASC, as with
other ACE inhibitors, monitoring of white blood cell counts should be considered
for patients who have collagen-vascular disease, especially if the disease is
associated with impaired renal function. Available data from clinical trials
of UNIVASC are insufficient to show that UNIVASC does not cause agranulocytosis
at rates similar to captopril.
Fetal/Neonatal Morbidity and Mortality
ACE inhibitors can cause fetal and neonatal morbidity and death when administered
to pregnant women. Several dozen cases have been reported in the world literature.
When pregnancy is detected, ACE inhibitors should be discontinued as soon as
possible.
The use of ACE inhibitors during the second and third trimesters of pregnancy
has been associated with fetal and neonatal injury, including hypotension, neonatal
skull hypoplasia, anuria, reversible or irreversible renal failure, and death.
Oligohydramnios has also been reported, presumably resulting from decreased fetal renal function; oligohydramnios in this setting has been associated with fetal limb contractures, craniofacial deformation, and hypoplastic lung development. Prematurity, intrauterine growth retardation, and patent ductus arteriosus have also been reported, although it is not clear whether these were caused by the ACE inhibitor exposure.
Fetal and neonatal morbidity do not appear to have resulted from intrauterine ACE inhibitor exposure limited to the first trimester. Mothers who have used ACE inhibitors only during the first trimester should be informed of this. Nonetheless, when patients become pregnant, physicians should make every effort to discontinue the use of moexipril as soon as possible. Rarely (probably less often than once in every thousand pregnancies), no alternative to ACE inhibitors will be found. In these rare cases, the mothers should be apprised of the potential hazards to their fetuses, and serial ultrasound examinations should be performed to assess the intraamniotic environment.
If oligohydramnios is observed, moexipril should be discontinued unless it is considered life-saving for the mother. Contraction stress testing (CST), a non-stress test (NST), or biophysical profiling (BPP) may be appropriate, depending upon the week of pregnancy. Patients and physicians should be aware, however, that oligo-hydramnios may not be detected until after the fetus has sustained irreversible injury.
Infants with histories of in utero exposure to ACE inhibitors should
be closely observed for hypotension, oliguria, and hyperkalemia. If oliguria
occurs, attention should be directed toward support of blood pressure and renal
perfusion. Exchange transfusion or peritoneal dialysis may be required as means
of reversing hypoten-sion and/or substituting for disordered renal function.
Theoretically, the ACE inhibitor could be removed from the neonatal circulation
by exchange transfusion, but no experience with this procedure has been reported.
No embryotoxic, fetotoxic, or teratogenic effects were seen in rats or in rabbits
treated with up to 90.9 and 0.7 times, respectively, the Maximum Recommended
Human Dose (MRHD) on a mg/m2 basis.
Hepatic Failure
Rarely, ACE inhibitors have been associated with a syndrome that starts with cholestatic jaundice and progresses to fulminant hepatic necrosis and sometimes death. The mechanism of this syndrome is not understood. Patients receiving ACE inhibitors who develop jaundice or marked elevations of hepatic enzymes should discontinue the ACE inhibitor and receive appropriate medical follow-up.