Sedatives and Hypnotics

Sedatives and Hypnotics

INTRODUCTION

Sedatives are central nervous system (CNS) depressant drugs that reduce excitement, tension, and produce relaxation. Hypnotics are drugs that depress the CNS and produce sleep similar to that of natural sleep. Both sedative and hypnotic action may reside in the same drug. At lower dose, the drug may act as sedative, while at a higher dose the same drug may act as hypnotic.

Agents used as sedatives and hypnotics include a large number of compounds of diverse chemical structure given in classification and pharmacological properties, which have the common ability to induce a nonselective, reversible depression of the CNS.

Sedative and hypnotic drugs are frequently used in preanaesthetic medication and as an adjunctive therapy in psychiatry. A large number of sedative and hypnotic drugs cross the placental barrier, consequently their chronic use during pregnancy may cause withdrawal effect in the newborn infant. Many of these substances are excreted into the breast milk, and hence, their chronic use during breast-feeding may cause sedation to the infant.

Sedatives and hypnotics are also used as the following:

• antianxiety agents

• anticonvulsants

• muscle relaxants

• general anaesthetics

• preanaesthetic medication

• antipsychiatrics

• to potentiate analgesic drugs

• adjuvant to anaesthesia

• a co-drug in the treatment of hypertension

The clinical pharmacology of the sedatives and hypnotics include the following:

Treatment of Anxiety States

The psychological behaviour and physiological responses that characterizes anxiety may be in many forms. Typically, the psychic awareness of anxiety is accompanied by an enhanced motor tension and autonomic hyperactivity. The benzodiazepines continue to be widely used for the management of anxiety states. Since anxiety symptoms may be relieved by many benzodiazepines, it is not easy to demonstrate the superiority of one individual drug over another.

Treatment of Sleep Problems

Nonpharmacological therapies are sometimes useful for sleep problems including proper diet and exercise, avoiding stimulants before retiring and ensuring a comfortable sleeping environment. In some cases, the patient will need and should be given a sedative and hypnotic. Benzodiazepines can cause a dose-dependent decrease in both rapid eyeball movement and non rapid eyeball movement and slowly cause sleep, although to a lesser extent than barbiturates. Zolpidem and zaleplon are less likely to change sleep pattern than the benzodiazepines.

Other Therapeutic Uses

Long-acting drugs such as chlordiazepoxide, diazepam, and to a lesser extent phenobarbital are administered in progressively decreasing doses to patients during withdrawal from psychological dependence on ethanol or other sedative hypnotics. Meprobamate and other benzodiazepines are frequently used as skeletal muscle relaxants.