A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Tenormin Warnings, Precautions, Pregnancy, Nursing, Abuse - Atenolol
Tenormin Warnings, Precautions, Pregnancy, Nursing, Abuse - Atenolol
WARNINGS
Cardiac Failure: Sympathetic stimulation
is necessary in supporting circulatory function
in congestive heart failure,
and beta blockade carries the potential
hazard of further depressing myocardial contractility and precipitating
more severe failure. In patients
who have congestive heart failure
controlled by digitalis
and/or diuretics, atenolol should be administered cautiously. Both digitalis
and atenolol
AV conduction.
In patients with acute myocardial
infarction, cardiac failure
which is not promptly and effectively controlled by 80 mg
of intravenous furosemide
or equivalent therapy is
a contraindication
to beta-blocker treatment.
In Patients Without a History of Cardiac Failure: Continued
depression of the myocardium
with beta-blocking agents over a period
of time can, in some cases, lead
to cardiac failure. At
the first sign or symptom of
impending cardiac failure,
patients should be fully digitalized and/or be given a diuretic
and the response observed
closely. If cardiac failure continues despite adequate digitalization
and diuresis, atenolol should be withdrawn. (See DOSAGE
AND ADMINISTRATION.)
| Cessation of Therapy with Atenolol: Patients with
coronary artery disease, who are being treated with atenolol, should
be advised against abrupt discontinuation of therapy. Severe exacerbation
of angina and the occurrence of myocardial
infarction and ventricular
arrhythmias have been reported in angina
patients following the abrupt discontinuation of therapy with beta-blockers.
The last two complications may occur with or without preceding exacerbation
of the angina pectoris.
As with other beta-blockers,
when discontinuation of atenolol
is planned, the patients should be carefully observed and advised
to limit physical
activity to a minimum. If the angina
worsens or acute coronary
insufficiency develops, it is recommended that atenolol
be promptly reinstituted, at least temporarily. Because coronary
artery disease is common
and may be unrecognized, it may be prudent not to discontinue atenolol
therapy abruptly even in patients treated only for hypertension
(see DOSAGE AND ADMINISTRATION). |
Concomitant Use of Calcium Channel Blockers: Bradycardia
and heart block
can occur and the left ventricular
end diastolic
pressure can rise when beta-blockers are administered with verapamil or
diltiazem. Patients with pre-existing conduction
abnormalities or left ventricular
dysfunction are particularly susceptible
(see PRECAUTIONS
).
Bronchospastic Diseases: PATIENTS WITH BRONCHOSPASTIC
DISEASE SHOULD, IN GENERAL, NOT RECEIVE BETA-BLOCKERS. Because of its
relative beta1 selectivity, however, atenolol
may be used with caution in patients with bronchospastic disease
who do not respond to, or cannot tolerate, other antihypertensive
treatment. Since beta1 selectivity is not absolute, the lowest
possible dose of atenolol
should be used with therapy initiated at 50 mg
and a beta2-stimulating agent
(bronchodilator) should be made available. If dosage
must be increased, dividing the dose should be considered in order
to achieve lower peak blood
levels.
Anesthesia and Major Surgery: It is not advisable to withdraw
beta-adrenoreceptor blocking
drugs prior to surgery in the majority of patients. However, care should
be taken when using anesthetic
agents such as those which may depress the myocardium. Vagal dominance,
if it occurs, may be corrected with atropine (1-2 mg
IV).
Atenolol, like other beta-blockers, is a competitive inhibitor
of beta-receptor agonists and its effects on the heart
can be reversed by administration of such agents: e.g., dobutamine
or isoproterenol with caution (see OVERDOSAGE).
Diabetes and Hypoglycemia: Atenolol should be used with
caution in diabetic patients
if a beta-blocking agent is
required. beta-blockers may mask
tachycardia occurring
with hypoglycemia, but other manifestations such as dizziness
and sweating may not be significantly
affected. At recommended doses
atenolol does not potentiate
insulin-induced hypoglycemia
and, unlike nonselective beta-blockers, does not delay recovery of blood
glucose to normal levels.
Thyrotoxicosis: Beta-adrenergic blockade
may mask certain clinical signs
(e.g., tachycardia) of hyperthyroidism. Abrupt withdrawal of beta
blockade might precipitate
a thyroid storm; therefore,
patients suspected of developing thyrotoxicosis
from whom atenolol therapy
is to be withdrawn should be monitored closely (see DOSAGE
AND ADMINISTRATION).
Pregnancy and Fetal Injury: Atenolol can cause
fetal harm when administered
to a pregnant woman. Atenolol
crosses the placental barrier
and appears in cord blood. Administration
of atenolol, starting in the second trimester
of pregnancy, has been associated with the birth
of infants that are small for gestational age. No studies have been performed
on the use of atenolol in
the first trimester, and the possibility of fetal
injury cannot be excluded. If this drug
is used during pregnancy, or if the patient becomes pregnant
while taking this drug, the patient
should be apprised of the potential
hazard to the fetus.
Atenolol has been shown to produce a dose-related increase in embryo/fetal
resorptions in rats at doses equal to or greater than 50 mg/kg/day or
25 or more times when maximum
recommended human antihypertensive
dose.* Although similar effects were not seen in rabbits, the compound
was not evaluated in rabbits at doses above 25 mg/kg/day or 12.5 times
the maximum recommended human
antihypertensive
dose.*
*Based on the maximum dose
of 100 mg/day in a 50 kg patient.
PRECAUTIONS
General
Tablets and I.V. Injection: Patients already on a beta-blocker
must be evaluated carefully before atenolol
is administered. Initial and subsequent atenolol
dosages can be adjusted downward depending on clinical observations including
pulse and blood
pressure. Atenolol may aggravate peripheral arterial
circulatory disorders.
Impaired Renal Function
The drug should be used with
caution in patients with impaired renal function (see DOSAGE
AND ADMINISTRATION).
Carcinogenesis, Mutagenesis, and Impairment of Fertility
Two long-term (maximum dosing duration
of 18 or 24 months) rat studies
and one long-term (maximum dosing duration
of 18 months) mouse study, each
employing dose levels as high
as 300 mg/kg/day or 150 times the maximum recommended human
antihypertensive
dose,* did not indicate a carcinogenic potential of atenolol. A third
(24 month) rat study, employing
doses of 500 and 1500 mg/kg/day (250 and 750 times the maximum
recommended human antihypertensive dose*) resulted in increased incidences
of benign adrenal medullary
tumors in males and females, mammary fibroadenomas in females, and anterior
pituitary adenomas and thyroid
parafollicular cell carcinomas
in males. No evidence of
a mutagenic potential of
atenolol was uncovered in
the dominant lethal
test (mouse), in vivo
cytogenetics test
(Chinese hamster) or Ames test
(S typhimurium).
Fertility of male or female
rats (evaluated at dose levels
as high as 200 mg/kg/day or 100 times the maximum
recommended human dose*) was
unaffected by atenolol administration.
*Based on the maximum dose
of 100 mg/day in a 50 kg patient.
Pregnancy Category D
See WARNINGS
, Pregnancy and Fetal Injury.
Nursing Mothers
Atenolol is excreted in human
breast milk
at a ratio of 1.5 to 6.8 when
compared to the concentration
in plasma. Caution should be exercised when atenolol is administered to
a nursing woman. Clinically
significant bradycardia
has been reported in breast
fed infants. Premature infants, or infants with impaired renal
function, may be more likely to develop adverse effects.
Pediatric Use
Safety and effectiveness
in pediatric patients have
not been established.
top
