INDICATIONS FOR USE OF ANTIHISTAMINES
The antihistamines are used primarily in allergic reactions, as sedatives, and in
the treatment/prevention of motion sickness and drug-induced Parkinsonism. These
preparations do not immunize the patient or protect him over a long period. Their
benefits are comparatively short-lived, provide only symptomatic relief, and do not
correct the underlying disorder.
CAUTIONS AND WARNINGS
The most common side effect of these preparations is drowsiness, which may
become so marked that deep sleep occurs. Other reactions include dizziness, dryness
of mouth and throat, nausea, muscular weakness, and gastrointestinal disturbances.
Patients receiving these products should be cautioned against drinking alcohol to avoid
the associated drowsiness.
GENERAL ANTIHISTAMINE PREPARATION
a. Diphenhydramine (Benadryl). This preparation is used for its
antihistamine, anti-Parkinson, and sedative properties. The usual dose varies
according to the age of the patient and the condition being treated. Diphenhydramine is
available in capsules, as an elixir, or in an injectable form.
b. Chlorpheniramine (Chlor-Trimeton). This product is used exclusively for
its antihistamine properties. It is available in tablets and as syrup.
c. Loratadine (Claritin) and Fexofenadine (Allegra). These products are
used to treat allergic reactions such as seasonal allergies. They do not cause
d. Additional Products. Other antihistamines commonly available include
Brompheniramine (Dimetane) and promethazine hydrochloride (Phenergan). These
products have similar properties, side effects, and dosage forms.
4-10. COMBINATION PREPARATION
a. Brompheniramine, Phenylpropanolamine (Dimetapp). This product is
used for its antihistaminic and decongestant properties. The dose depends on the form
in which it is taken and the patient's age. It is available in tablet and elixir form.
b. Other Preparations. Other combination preparations that are available
include dexbrompheniramine and pseudoephedrine (Drixoral), triprolidine and
pseudoephedrine (Actifed), and phenylpropanolamine and chlorpheniramine