PRECAUTIONS
General
Because of potential effects of beta-adrenergic blocking
agents on blood pressure and pulse, these agents should be used with caution in
patients with cerebrovascular insufficiency. If signs or symptoms suggesting
reduced cerebral blood flow develop following initiation of therapy with
TIMOPTIC-XE, alternative therapy should be considered.
There have been reports of bacterial keratitis associated
with the use of multiple-dose containers of topical ophthalmic products. These
containers had been inadvertently contaminated by patients who, in most cases,
had a concurrent corneal disease or a disruption of the ocular epithelial
surface [see PRECAUTIONS, PATIENT INFORMATION].
Choroidal detachment after filtration procedures has been
reported with the administration of aqueous suppressant therapy (e.g. timolol).
Angle-closure Glaucoma
In patients with angle-closure glaucoma, the immediate
objective of treatment is to reopen the angle. This may require constricting
the pupil. Timolol maleate has little or no effect on the pupil. TIMOPTIC-XE
should not be used alone in the treatment of angle-closure glaucoma.
Anaphylaxis
While taking beta-blockers, patients with a history of
atopy or a history of severe anaphylactic reactions to a variety of allergens
may be more reactive to repeated accidental, diagnostic, or therapeutic
challenge with such allergens. Such patients may be unresponsive to the usual
doses of epinephrine used to treat anaphylactic reactions.
Muscle Weakness
Beta-adrenergic blockade has been reported to potentiate
muscle weakness consistent with certain myasthenic symptoms (e.g., diplopia,
ptosis, and generalized weakness). Timolol has been reported rarely to increase
muscle weakness in some patients with myasthenia gravis or myasthenic symptoms.
Information for Patients
Patients should be instructed to avoid allowing the tip
of the dispensing container to contact the eye or surrounding structures.
Patients should also be instructed that ocular solutions,
if handled improperly or if the tip of the dispensing container contacts the
eye or surrounding structures, can become contaminated by common bacteria known
to cause ocular infections. Serious damage to the eye and subsequent loss of
vision may result from using contaminated solutions [see PRECAUTIONS, General].
Patients should also be advised that if they have ocular
surgery or develop an intercurrent ocular condition (e.g., trauma or
infection), they should immediately seek their physician's advice concerning
the continued use of the present multidose container.
Patients should be instructed to invert the closed
container and shake once before each use. It is not necessary to shake the
container more than once.
Patients requiring concomitant topical ophthalmic
medications should be instructed to administer these at least 10 minutes before
instilling TIMOPTIC-XE.
Patients with bronchial asthma, a history of bronchial
asthma, severe chronic obstructive pulmonary disease, sinus bradycardia, second
or third degree atrioventricular block, or cardiac failure should be advised
not to take this product [see CONTRAINDICATIONS].
Transient blurred vision, generally lasting from 30
seconds to 5 minutes, following instillation, and potential visual disturbances
may impair the ability to perform hazardous tasks such as operating machinery
or driving a motor vehicle.
Carcinogenesis, Mutagenesis, Impairment Of Fertility
In a two-year study of timolol maleate administered
orally to rats, there was a statistically significant increase in the incidence
of adrenal pheochromocytomas in male rats administered 300 mg/kg/day
(approximately 42,000 times the systemic exposure following the maximum
recommended human ophthalmic dose). Similar differences were not observed in
rats administered oral doses equivalent to approximately 14,000 times the
maximum recommended human ophthalmic dose.
In a lifetime oral study in mice, there were
statistically significant increases in the incidence of benign and malignant
pulmonary tumors, benign uterine polyps, and mammary adenocarcinomas in female
mice at 500 mg/kg/day (approximately 71,000 times the systemic exposure
following the maximum recommended human ophthalmic dose), but not at 5 or 50
mg/kg/day (approximately 700 or 7,000, respectively, times the systemic
exposure following the maximum recommended human ophthalmic dose). In a
subsequent study in female mice, in which post-mortem examinations were limited
to the uterus and the lungs, a statistically significant increase in the
incidence of pulmonary tumors was again observed at 500 mg/kg/day.
The increased occurrence of mammary adenocarcinomas was
associated with elevations in serum prolactin, which occurred in female mice
administered oral timolol at 500 mg/kg/day, but not at oral doses of 5 or 50
mg/kg/day. An increased incidence of mammary adenocarcinomas in rodents has
been associated with administration of several other therapeutic agents that
elevate serum prolactin, but no correlation between serum prolactin levels and
mammary tumors has been established in humans.
Furthermore, in adult human female subjects who received
oral dosages of up to 60 mg of timolol maleate (the maximum recommended human
oral dosage), there were no clinically meaningful changes in serum prolactin.
Timolol maleate was devoid of mutagenic potential when
tested in vivo (mouse) in the micronucleus test and cytogenetic assay (doses up
to 800 mg) and in vitro in a neoplastic cell transformation assay (up to 100
mcg/mL). In Ames tests, the highest concentrations of timolol employed, 5,000
or 10,000 mcg/plate, were associated with statistically significant elevations
of revertants observed with tester strain TA 100 (in seven replicate assays),
but not in the remaining three strains. In the assays with tester strain TA
100, no consistent dose response relationship was observed, and the ratio of
test to control revertants did not reach 2. A ratio of 2 is usually considered
the criterion for a positive Ames test.
Reproduction and fertility studies in rats demonstrated
no adverse effect on male or female fertility at doses up to 21,000 times the
systemic exposure following the maximum recommended human ophthalmic dose.
Pregnancy
Teratogenic Effects
Teratogenicity studies with timolol in mice, rats, and
rabbits at oral doses up to 50 mg/kg/day (7,000 times the systemic exposure
following the maximum recommended human ophthalmic dose) demonstrated no
evidence of fetal malformations. Although delayed fetal ossification was
observed at this dose in rats, there were no adverse effects on postnatal
development of offspring. Doses of 1000 mg/kg/day (142,000 times the systemic
exposure following the maximum recommended human ophthalmic dose) were
maternotoxic in mice and resulted in an increased number of fetal resorptions.
Increased fetal resorptions were also seen in rabbits at doses of 14,000 times
the systemic exposure following the maximum recommended human ophthalmic dose,
in this case without apparent maternotoxicity.
There are no adequate and well-controlled studies in
pregnant women. TIMOPTIC-XE should be used during pregnancy only if the potential
benefit justifies the potential risk to the fetus.
Nursing Mothers
Timolol maleate has been detected in human milk following
oral and ophthalmic drug administration. Because of the potential for serious
adverse reactions from TIMOPTICXE in nursing infants, a decision should be made
whether to discontinue nursing or to discontinue the drug, taking into account
the importance of the drug to the mother.
Pediatric Use
Safety and effectiveness in pediatric patients have not
been established.
Geriatric Use
No overall differences in safety or effectiveness have
been observed between elderly and younger patients.