GENERIC NAME: timolol ophthalmic solution
BRAND NAME: Timoptic
DRUG CLASS AND MECHANISM: Timolol is a beta- adrenergic
blocking
agent. Like other beta-adrenergic blocking agents, it mainly
blocks the
action of the sympathetic (adrenergic) nervous system, for
example, on the
heart. In addition to its effect on the heart, timolol causes a
reduction
of the pressure within the eye (intraocular pressure). This
effect is
thought to be caused by a reduction in the production of the
liquid
(aqueous humor) within the eye. The precise mechanism of this
effect is
not known. The reduction in intraocular pressure reduces the
risk of
damage to the optic nerve and loss of vision in patients with
glaucoma.
Timolol was approved by the FDA for ocular use in 1978.
PRESCRIPTION: yes
GENERIC AVAILABLE: yes
PREPARATIONS: Ophthalmic solution: 0.25%, 0.5%. There
is also a
gel-forming solution (Timoptic-XE) in a 0.25% and 0.5%
concentration.
STORAGE: Ophthalmic solution should be kept at room
temperature, 15-30°C
(59-86°F) and protected for
direct light.
PRESCRIBED FOR: Timolol is used for the treatment of
glaucoma.
(Oral timolol tablets are used for treating high blood pressure
and angina,
but this dosage form is not discussed here.)
DOSING: Both hands should be washed before each use of
timolol
or any other eye medication. The head should be tilted back and
the lower
lid pulled down with the index finger to form a pouch. The tip
of the
dropper should not be touched to the eye or eyelid. The bottle
should be
squeezed slightly to allow the prescribed number of drops into
the pouch.
The eye is closed gently for 1 to 2 minutes without blinking.
The usual
dose is one drop into the affected eye twice daily. Timoptic-XE
gel
forming solution usually is used once daily.
DRUG INTERACTIONS: Combined use of oral beta-
adrenergic
blocking agents, for example, propranolol (Inderal), atenolol (Tenormin),
metoprolol (Lopressor) or carvedilol (Coreg) with ophthalmic
timolol can
result in additive effects. Thus, patients may experience
excessively low
blood pressure or reductions in heart rate.
PREGNANCY: Although there are no human studies that
have
examined the effects of oral timolol on the fetus, animal
studies have
shown adverse effects. Therefore, the physician must weigh the
potential
risks to the fetus against the potential benefits to the
mother. It is
unknown if the small amount of timolol that penetrates into the
blood
after administration into the eye affects the fetus.
NURSING MOTHERS: Concentrations of timolol in breast
milk can
be three times those in the mother's blood after oral
administration. It
is not known how much, if any timolol appears in breast milk
after
administration into the eye. Ideally, patients taking timolol
should avoid
breast-feeding.
SIDE EFFECTS: Ophthalmic timolol can cause irritation
to the
eye which may manifest as pain or dryness in some people.
Rarely, timolol
eye drops can result in side effects that are seen with other
oral beta
adrenergic blockers. For example, persons can experience
fatigue,
insomnia, nausea, slow heart rate, low blood pressure, cold
extremities,
and shortness of breath or wheezing.
Last Editorial Review: 5/11/1998
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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From the Doctors at MedicineNet.com  |
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- Beta Blockers - Learn more about Beta Blockers, a drug that treats angina and other heart rhythm disorders, migraines, high blood pressure, panic attacks, and tremors. Generic and brand names are included in the article. Source:MedicineNet
- Glaucoma - Get information about glaucoma and its symptoms, signs, and causes. Learn about treatment, prevention, and research on the leading cause of blindness. Source:MedicineNet
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