Effects Produced by Sedative-Hypnotic Agents.
(1) Sedation. To sedate means to calm; therefore, sedation refers to the act
of producing calm in a patient. You can also think of sedation as referring to a
decreased responsiveness to a constant level of stimulation. Small doses (small
amounts) of a sedative-hypnotic drug administered to a patient will produce sedation.
(2) Disinhibition. Disinhibition refers to actions a person may perform while
under the effects of a drug that he would not perform if he were not taking the drug.
This effect may be seen as euphoria, (feeling of well being or elation) in some patients
and is a potential source of abuse of these agents. Disinhibition is presumed because
of depression of a higher cortical (brain) center, which results in a resultant release of
lower brain centers from constant inhibitory influence. Larger doses of a sedative-
hypnotic agent will produce this effect.
(3) Relief of anxiety. This particular effect probably cannot be separated
from the sedative and euphoriant effects produced by the sedative-hypnotic agents.
(4) Sleep. Sedative-hypnotic induced sleep differs in several ways from
normal sleep. If a sufficiently large dose of any sedative-hypnotic agent is administered
to a patient, sleep will result; however, the dose of a particular agent required to
produce sleep will vary with the physiologic and psychologic state of the individual and
the environmental situation in which the drug is given.
(5) Anesthesia. State III of general anesthesia (surgical anesthesia--
unconsciousness and paralysis of reflexes) can be induced in humans with large doses
of sedative-hypnotic agents. Short- and ultra short-acting barbiturates are the only
drugs used as anesthetic agents from this class.
(6) Analgesia. Patients who have been deeply anesthetized with
barbiturates are totally unresponsive to pain.
(7) Anticonvulsant activity. All the barbiturates commonly used in clinical
practice are capable of inhibiting convulsions. Phenobarbital and other long-acting
drugs are selectively more effective at lower therapeutic doses in the treatment of
(8) Cardiovascular and respiratory effects. Sedative-hypnotic agents are
respiratory depressants that depress the respiratory system. Sedative-hypnotic agents
do not, when administered orally, produce significant cardiovascular effects.
(9) Dependence. Both psychic and physical dependence has been reported
with both the barbiturate and nonbarbiturate sedative-hypnotic agents. Dependence
usually occurs when sedative-hypnotics are given over a long period in large doses.
Therefore, continued administration of these agents is usually necessary to prevent a
withdrawal state in the patient.