CHAPTER 18 Ophthalmic Drugs
Quiz Yourself
1. Topical ophthalmic drug forms must be different from topical drug forms used on
the skin because they must be specially formulated to be nonirritating to the eye and
they are not interchangeable with topical drugs for the skin.
2. Silver nitrate is a topical anti-infective drug applied to the eyes of newborn infants to
prevent infection and possible blindness from gonorrhea (contracted from an
infected
birth canal). Silver nitrate has been used for many years and is the least expensive
drug for this problem. However, it can cause conjunctival irritation/swelling in the
newborn. Another topical anti-infective, erythromycin, is equally as effective in
preventing gonorrhea. It can prevent newborn eye infections from chlamydia as well.
It can also facilitate mother–child bonding because it does not produce conjunctival
irritation and swelling like silver nitrate; however, erythromycin is more expensive.
3. Histamine is produced when a foreign substance, such as pollen, animal dander, or
other antigen, enters the body, and antibodies from the immune system attach to the
antigen and form an antigen–antibody complex that the body can destroy. Histamine
causes vasodilation, and the blood vessels and tissues become swollen, inflamed,
and red. Histamine also irritates tissues directly, causing pain and itching.
4. Three categories of drugs that are used to treat allergy symptoms in the eyes are
topical antihistamine drugs, topical mast cell stabilizer drugs, and topical
decongestant drugs.
5. Prostaglandin F agonist drugs for glaucoma stimulate prostaglandin F receptors,
which increases the outflow of aqueous humor and decreases the intraocular
pressure. Carbonic anhydrase inhibitor drugs block the enzyme carbonic anhydrase,
which is active in the production of aqueous humor. Beta-blocker drugs block beta
receptors in the eye and this decreases the production of aqueous humor. Alpha
receptor stimulator drugs stimulate alpha receptors to decrease the production
of aqueous humor and increase its outflow. Sympathomimetic drugs mimic the
action of epinephrine to increase the outflow of aqueous humor. Miotic drugs act
like acetylcholine to cause the pupil to constrict and increase the outflow of aqueous
humor. Cholinesterase inhibitor drugs inhibit cholinesterase, an enzyme that
destroys acetylcholine; with acetylcholine active, the pupil constricts and this
increases the outflow of aqueous humor.
6. Beta-blocker drugs have an advantage over other miotic drugs used to treat
glaucoma in that they do not constrict the pupil and therefore do not cause blurring
of vision or night blindness.
7. Mydriatic drugs are used to dilate the pupil, paralyze the muscles of accommodation
of the iris, and prepare the eye for internal examination.
8. Antihistamine ophthalmic drugs block histamine receptors in the eye to block the
effects of histamine released during allergic reactions. Ophthalmic mast cell
inhibitors stabilize the cell membrane of mast cells and prevent them from releasing
any histamine.
9. Botulinum toxin type A is a toxin that is injected into eye muscles to paralyze the
muscle fibers and allow them to lengthen. It is used to treat blepharospasm,
nystagmus, and strabismus.
10. a. Topical antibiotic drug for bacterial infections
b. Monoclonal antibody drug used to treat macular degeneration
c. Prostaglandin F agonist drug used to treat glaucoma
d. Carbonic anhydrase inhibitor drug for glaucoma
e. Topical corticosteroid drug for eye inflammation
f. Topical NSAID for eye inflammation
g. Antiviral drug implant for CMV in patients with AIDS
h. Topical mast cell stabilizer drug for eye allergies
i. Beta-blocker drug for glaucoma
j. Topical decongestant drug for eye allergies
k. Topical antibiotic drug for bacterial eye infections
l. Corticosteroid drug for eye inflammation
m. Mydriatic drug to dilate the pupil
Clinical Applications Questions
1. a. Timoptic
b. Beta-blocker drug
c. It blocks beta receptors in the eye. This decreases the production of aqueous
humor to decrease the intraocular pressure.
d. 0.25%
e. Ophthalmic drops
f. Write on the label: 1 drop(s) in both eyes twice a day.
2. a. Over-the-counter drug (label says “Available without a prescription”)
b. naphazoline, pheniramine
c. decongestant drug and antihistamine drug
d. used to treat allergy symptoms in the eyes
3. a. Garamycin
b. Antibiotic drug
c. Bacterial infections in the eye.
d. Ophthalmic solution (liquid)