Glucocorticoids
Glucocorticoids (corticosteroids) include Dexamethasone (Decadron) and
methylprednisolone (Solu-Medrol). They are administered intravenously for
short-term use. This reduces the side effects caused by using glucocorticoids.
(See Chapter 12 for a discussion on the use of steroids.)Cannabinoids (for cancer patients)
The cannabinoids act on the cerebral cortex and have the same side effects and
adverse reactions as antihistamines and anticholinergic. These include drowsi-
ness, dry mouth, blurred vision, tachycardia, and constipation. Cannabinoids
include dronabinol and nabilone. These drugs should not be administered to
glaucoma patients because they dilate the pupils (mydriasis). They are contra-
indicated for use in patients with psychiatric disorders and also used as an
appetite stimulant for patients with AIDS. Side effects include mood changes,
euphoria, drowsiness, dizziness, headaches, depersonalization, nightmares, con-
fusion, incoordination, memory lapse, dry mouth, orthostatic hypotension, hyper-
tension, and tachycardia. Less common symptoms include depression, anxiety,
and manic psychosis.MISCELLANEOUS
Miscellaneous antiemetics include benzquinamide hydrochloride (Emete-Con),
diphenidol (Vontrol), and trimethobenzamide (Tigan). They do not act strictly as
antihistamines, anticholinergics, or phenothiazides. They suppress the impulses to
the CTZ. Diphenidol also prevents vertigo by inhibiting impulses to the vestibu-
lar area. Benzquinamide appears to have antiemetic, antihistaminic, and anti-
cholinergic effects. It inhibits stimulation to the CTZ center and decreases
activity in the vomiting center. It can also increase cardiac output and elevate
blood pressure. Side effects and adverse reactions of the miscellaneous antiemetics
include drowsiness and anticholinergic symptoms such as dry mouth, increased
heart rate, urine retention, constipation, and blurred vision. Benzquinamide
should be used cautiously in clients with cardiac problems such as dysrhythmias.
It can cause CNS stimulation, including nervousness, excitement, and insomnia.
Trimethobenzamide can cause hypotension, diarrhea, and EPS.
A list of antiemetic drugs are in the Appendix. Detailed tables show doses,
recommendations, expectations, side effects, contraindications, and more; avail-
able on the book’s Web site (see URL in Appendix).(^334) CHAPTER 18 Gastrointestinal System