b. As you might anticipate, when increasingly larger doses of a drug are
administered to the patient, the effects produced by the drug cause stimulation of more
than one area.
c. Some central nervous system stimulants produce high levels of stimulation
at other sites in the body (for example, the heart). In some cases, the usefulness of
several CNS agents is limited because of the stimulation they produce in body organs.
Section II. CEREBRAL OR PSYCHOMOTOR AGENTS
A variety of agents are classified as cerebral or psychomotor central nervous
system agents. These drugs have one characteristic in common: they primarily
stimulate the cerebral cortex of the brain.
10-5. CLASSES OF CEREBRAL OR PSYCHOMOTOR CENTRAL NERVOUS
a. The Xanthine Derivatives. The xanthine derivatives have several
pharmacological effects. One, they directly relax the smooth muscle of the bronchi and
pulmonary blood vessels. By such dilation of the bronchi, more oxygen can be drawn
into the lungs. Two, they stimulate the central nervous system and produce diuresis
(they increase the production of urine) by direct action on the kidney. There are several
examples of xanthine derivatives:
(1) Caffeine. Caffeine is found in coffee, tea, and in kola nuts (used to
make some soft drinks). Caffeine is a stimulant that has been long used as a morning
"picker-upper" for workers and students. Caffeine is found in some headache remedies
products promoted to prevent drowsiness, and in some products designed to suppress
appetite (in these preparations caffeine acts to stimulate the person). Although caffeine
does have some desirable qualities (that is, small doses of the drug can promote better
performance on tasks like typing and thinking), it is possible for a person to develop a
psychological dependence on the drug. Withdrawal of the drug results in some persons'
having mild withdrawal symptoms (for example, headaches).
(2) Aminophylline (Theophylline ethylenediamine). This drug is used in
the treatment of bronchial asthma. It is given intravenously to provide rapid relief of
pulmonary edema and dyspnea seen in the acute congestive heart failure patient
because it increases cardiac output, slightly increases venous pressure, and relaxes the
bronchial muscle. Side effects associated with the oral administration of this agent
include nausea, vomiting, and nervousness. The patient should be informed to take this
medication with food. The medication is supplied in 100 and 200-milligram tablets, 250