4-11. ANTIPRURITIC PREPARATIONS
a. Cyproheptadine (Periactin). This drug is used to control itching caused by
allergic reactions. It causes drowsiness and should not be taken with alcohol.
Periactin is available in tablet and syrup form.
b. Other Preparations. Other antipruritic preparations include trimeprazine
tartrate (Temaril) and hydroxyzine hydrochloride (Atarax).
4-12. HISTAMINE INHIBITORS
a. Cromolyn sodium (Intal) is a successful anti-asthma prophylactic drug that
was produced as a result of knowledge of the mechanisms of allergic reactions. It acts
by inhibiting the granulation of pulmonary mast cells, thereby preventing the release of
histamine responsible for causing asthmatic symptoms; it has no value in stopping an
allergic attack already in progress.
b. Cromolyn sodium is administered by inhalation and is used in the
management of patients with severe bronchial asthma. It is also indicated in certain
patients to prevent exercise-induced bronchospasm.
c. Following therapy, cromolyn sodium may cause mild throat irritation,
coughing, and hoarseness. On occasion, it has been known to produce
bronchospasms. Esophageal irritation is relieved by antacids or by drinking a glass of
milk before each treatment to protect the gastrointestinal mucosa from direct contact
with the drug. The drug demonstrates a low level of toxicity, but some hypersensitivity
and allergy have occurred.
4-13. H2 ANTAGONISTS
a. Cimetidine (Tagamet) is an antihistamine that selectively and competitively
inhibits the action of histamine by occupying the H2 receptors of the gastrointestinal
mucosa. This action inhibits basal gastric ulcers and controls pathogenic
b. The drug is available in tablet and syrup form for oral administration or may
be administered intramuscularly or intravenously. It may be essential to administer
antacids with cimetidine as needed for relief of pain. However, they should not be given
c. Side effects include mild transient diarrhea, muscular pain, dizziness, and
skin rashes. A few cases of reversible confusion states have been reported in the
elderly, probably because of overdose. Mild gynecomastia been observed in patients
treated with this drug for one month or longer. It is relatively nontoxic. Cimetidine does
not cause drowsiness like the H1 antagonists.