A Textbook of Clinical Pharmacology and Therapeutics

●Introduction 105

●Sleep difficulties and insomnia 105

●Anxiety 107

CHAPTER 18

HYPNOTICS AND ANXIOLYTICS

INTRODUCTION

Hypnotics induce sleep and anxiolytics reduce anxiety. There
is considerable overlap between them. Thus, drugs that induce
sleep also reduce anxiety, and as most anxiolytic drugs are
sedative, will assist sleep when given at night. Neither hypnotics
nor anxiolytics are suitable for the long-term management of
insomnia or anxiety, due to tolerance and dependence. In this
chapter, we discuss the management – both non-pharmacological
and pharmacological – of sleep difficulties and of anxiety, and
this is summarized in Figure 18.1.

SLEEP DIFFICULTIES AND INSOMNIA

Insomnia is common. Although no general optimal sleep
duration can be defined, sleep requirements decline in old age.
The average adult requires seven to eight hours, but some func-
tion well on as little as four hours, while others perceive more
than nine hours to be necessary. Dissatisfaction with sleep report-
edly occurs in 35% of adults and is most frequent in women
aged over 65 years. Insomnia may include complaints such as
difficulty in falling or staying asleep, and waking unrefreshed.
Hypnotics are widely prescribed despite their ineffectiveness
in chronic insomnia, as well as the problems associated with
their long-term use. Persistent insomnia is a risk factor for or
precursor of mood disorders, and may be associated with an
increased incidence of daytime sleepiness predisposing to road
traffic accidents, social and work-related problems. Insomnia
lasting only a few days is commonly the result of acute stress,
acute medical illness or jet lag. Insomnia lasting longer than
three weeks is ‘chronic’.

SLEEP

Although we spend about one-third of our lives asleep, the
function of sleep is not known. Sleep consists of two alternat-
ing states, namely rapid eye movement (REM) sleep and
non-REM sleep. During REM sleep, dreaming occurs. This is
accompanied by maintenance of synaptic connections and

increased cerebral blood flow. Non-REM sleep includes sleep

of different depths, and in the deepest form the electroenceph-

alogram (EEG) shows a slow wave pattern, growth hormone

is secreted and protein synthesis occurs.

Drugs produce states that superficially resemble physio-

logical sleep, but lack the normal mixture of REM and non-

REM phases. Hypnotics usually suppress REM sleep, and when

discontinued, there is an excess of REM (rebound) which is

associated with troubled dreams punctuated by repeated wak-

enings. During this withdrawal state, falling from wakefulness

to non-REM sleep is also inhibited by feelings of tension and

anxiety. The result is that both patient and doctor are tempted

to restart medication to suppress the withdrawal phenomena,

resulting in a vicious cycle.

GENERAL PRINCIPLES OF MANAGEMENT OF

INSOMNIA

It is important to exclude causes of insomnia that require treat-

ing in their own right. These include:

• pain (e.g. due to arthritis or dyspepsia);


• dyspnoea (e.g. as a result of left ventricular failure,
  bronchospasm or cough);


• frequency of micturition;


• full bladder and/or loaded colon in the elderly;


• drugs (see Table 18.1);

Table 18.1:Drugs that may cause sleep disturbances

Caffeine

Nicotine

Alcohol withdrawal

Benzodiazepine withdrawal

Amphetamines

Certain antidepressants (e.g. imipramine)

Ecstasy

Drugs that can cause nightmares (e.g. cimetidine, corticosteroids,

digoxin and propranolol)