10-4. EXAMPLES OF CHOLINERGIC BLOCKING AGENTS
a. Atropine. Atropine is a classic example of the cholinergic blockers. It is
found alone and in combination with a wide-variety of other drugs. As an ophthalmic
preparation (Isopto-Atropine), it is used as a cycloplegic and as a mydriatic. Side
effects associated with the use of atropine are unsteadiness, hallucinations, unusual
dryness of mouth, and increased sensitivity of eyes to light. Patients who have
glaucoma should use caution when using this preparation.
b. Scopolamine. Scopolamine is another classic example of the cholinergic
blockers. Like atropine, scopolamine is found in a variety of medications. It is found in
some over-the-counter cold medications. It is present in these products because of the
drying effect it produces. In its ophthalmic form it is used as a mydriatic and as a
cycloplegic. Side effects that can be caused by this drug include unsteadiness, fever,
flushing, or redness of the face, hallucinations, and increased sensitivity of the eyes to
light. Patients who have glaucoma should use this preparation with caution.
c. Homatropine Hydrobomide (Isopto-Homatropine). This ophthalmic
preparation is used as a mydriatic and as a cycloplegic. The side effects associated
with this drug are the same as those associated with atropine and scopolamine (above).
Patients who have glaucoma should use this preparation with caution.
d. Cyclopentolate (Cyclogyl). This cholinergic blocker is used as a mydriatic
and as a cycloplegic. Cyclopentolate can produce side effects such as unsteadiness,
fever, redness of the face, hallucinations, or increased thirst. Patients who have
glaucoma should use Cyclopentolate with caution.
e. Belladonna Alkaloids with Phenobarbital (Donnatal). This preparation is
used as an antispasmodic. Side effects associated with this agent are eye pain (from
increased intraocular pressure), constipation, drowsiness, and dryness of the mouth.
Patients taking this preparation should be informed of several things. Do not drink
alcohol while taking Donnatal (because of central nervous system depression). Never
take this preparation within one hour of taking antacid (the effectiveness of the
Donnatal will be reduced). This drug may cause drowsiness in some patients;
therefore, know how the drug will affect him before he drives or performs any job that
requires alertness. Belladonna alkaloids sometimes make patients perspire less (this
results in increased body temperature); therefore, do not become overheated because
of excessive exercise or hot weather.
f. Propantheline Bromide (Pro-Banthine). This agent is used in the
treatment of peptic ulcers. Side effects associated with this drug include constipation,
difficult urination (because of decreased muscle tone of the urinary bladder), eye pain
(from increased intraocular pressure), and dizziness. Patients taking this medication
should be informed of several things. Propantheline can produce drowsiness in some
patients; therefore, they should ensure they know how the medicine will affect them
before they drive or perform activities that require mental alertness. Sometimes