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
Timoptic Overdose, Contraindications and Information - Timolol Maleate
Timoptic Overdose, Contraindications and Information - Timolol Maleate
OVERDOSE
Tablets, Ophthalmic Solutions, and Ophthalmic Gel Forming Solution
There have been reports of inadvertent overdosage with timolol
maleate ophthalmic solution
resulting in systemic
effects similar to those seen with systemic
beta-adrenergic blocking
agents such as dizziness, headache, shortness of breath, bradycardia,
bronchospasm, and cardiac
arrest (see ADVERSE
REACTIONS).
Overdosage has been reported with timolol maleate tablets. A 30-year-old
female ingested 650 mg of
timolol maleate (maximum recommended oral
daily dose is 60 mg) and experienced second and third degree
heart block. She recovered
without treatment
but approximately two months later developed irregular heartbeat,
hypertension, dizziness, tinnitus, faintness, increased pulse rate,
and borderline first
degree heart
block.
Significant lethality was observed in female
rats and female mice
after a single dose of
900 and 1190 mg/kg (5310 and 3570 mg/m2) of timolol maleate,
respectively.
An in vitro hemodialysis
study, using 14C timolol added to human
plasma or whole blood,
showed that timolol was readily dialyzed from these fluids; however,
a study of patients with renal
failure showed that
timolol did not dialyze
readily.
Additional Information for Ophthalmic Gel Forming Solution:
No data are available in regard to human
overdosage with or accidental oral ingestion
of timolol maleate ophthalmic
gel forming solution.
Tablets
The most common signs and symptoms to be expected with overdosage
with a beta-adrenergic receptor
blocking agent
are symptomatic
bradycardia, hypotension, bronchospasm, and acute
cardiac failure. Therapy
with timolol maleate should be discontinued and the patient
observed closely. The following additional therapeutic
measures should be considered:
1. Gastric Lavage.
2. Symptomatic Bradycardia: Use atropine sulfate
intravenously in a dosage
of 0.25 mg to 2 mg
to induce vagal blockade.
If bradycardia persists,
intravenous isoproterenol
HCl should be administered cautiously. In
refractory cases the use of a transvenous
cardiac pacemaker may
be considered.
3. Hypotension: Use sympathomimetic
pressor drug therapy,
such as dopamine, dobutamine or levarterenol. In
refractory cases the use of glucagon
HCl has been reported to be useful.
4. Bronchospasm: Use isoproterenol HCl. Additional
therapy with aminophylline
may be considered.
5. Acute Cardiac Failure: Conventional therapy
with digitalis, diuretics, and oxygen
should be instituted immediately. In refractory cases the use of
intravenous aminophylline
is suggested. This may be followed if necessary by glucagon
HCl which has been reported to be useful.
6. Heart Block (Second or Third Degree): Use
isoproterenol HCl or a transvenous
cardiac pacemaker.
CONTRAINDICATIONS
Timolol maleate is contraindicated in patients with bronchial
asthma or with a history of bronchial
asthma, or severe chronic
obstructive pulmonary disease (see WARNINGS);
sinus bradycardia; second
or third degree atrioventricular
block; overt cardiac
failure (see WARNINGS);
cardiogenic shock; or hypersensitivity to any component
of this product.
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