Oral Meds: Antihistamines
There are those patients who present to the eye doctor with allergic
conjunctivitis as a component of generalized allergic disease,
including sinusitis and rhinitis.
An exclusively topical approach works well in most cases of
ocular allergy. However, a more generalized allergy expression
may require an oral antihistamine. OTC drugs such as diphenhydramine
(Benadryl) or chlorpheniramine (Chlor-Trimeton) work well,
but exhibit sedation as a limiting side effect. Prescription
antihistamines with little or no sedation potential include:
• Cetirizine (Zyrtec) 5 or 10mg qd
• Desloratadine (Clarinex) 5mg qd
• Fexofenadine (Allegra) 60mg bid; 180mg qd
Loratadine (Claritin) 10mg qd is an excellent OTC non-sedating
antihistamine and has largely precluded the need for its prescription
counterparts. Although Zyrtec is technically not listed as
a non-sedating antihistamine, its pharmacology and side effect
profile are nearly identical to Claritin and Allegra.
Since Clarinex is brand new, we are not sure yet where it
will fit in. Our guess is that it will replace Claritin as
our favorite.
Remember that all oral antihistamines can diminish the volume
of the precorneal tear film, which can cause, or increase,
symptoms of dry eyes. As with all the other oral meds, we don’t
use these often, but when indicated, they can be helpful.
In summary, it can be seen that orally administered medicines
can indeed play a critical role in achieving tissue restoration
in a select subset of ocular conditions. We must stress the
need to have Drug Facts and Comparisons or other authoritative
reference available prior to prescribing any oral medicines.
If we are to continue to provide an enhanced level of service
to our patients, we must embrace these medicines as part of
our comprehensive armamentarium.
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