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Sedatives and Hypnotics -An Introduction

Sedatives and hypontics are the most desired drugs.

Sedation

Decreased responsiveness to a constant level of stimulation.(Psychomotor retardation)

Reduced excitation, calming and relaxing effect, without excessive drowsiness.

Sedatives

These drugs exert a calming effect and reduce excitement in hyperactive individuals, with little or no effect on motor or mental functions.

Hypnosis

Increased sedation  –>     increased drowsiness    –>     induction of state of sleep

Hypnotics

The drugs which produce drowsiness & encourage the onset & maintenance of a state of sleep.

Hypnotics produce drowsiness and facilitate the onset of sleep, resembling normal sleep pattern, causing psychomotor slowing.

Sleep consists of REM and non-REM sleep. REM is for 20-30% of time. 80-100 minute cycle is repeated.

It is further divided into four stages:

Stages of sleep Wave pattern
  1. Dosing stage
a, b
  1. Patient goes to sleep
a, b theta
  1. Slow wave sleep
Theta, delta, K complexes sleep spindles
  1. Slow wave sleep
Delta (high voltage)
Wave Frequency Voltage
Delta < 4/sec 50 µ v
Theta 4-7/sec May vary from 0-300 µv
Alpha 8-13/sec
Beta 14-50/sec
K complex brief high voltage activity
Sleep spindles 10-14/sec 50 µv interspersed  with delta wave

The drug should resemble normal sleep pattern. Normal architecture should not be disturbed. Large number of drugs are available.

Actually all drugs are depressants of CNS. Some non-selective, like barbiturates cause non-selective depression of CNS.

Non-selective drugs:

  1. Depress CNS –graded depression
  2. Sedative in small dose,

As dose is increased moderately, there is hypnosis,

Further higher dose produces general anesthesia.

As concentration is further increased, coma or even death may occur.

Dose should not exceed the level of hypnosis.

These drugs are also used for anxiety treatment, thus are anxiolytic drugs. All sedatives relieve anxiety, by causing sedation and drowsiness.

Anxiety

A subjective feeling , fear or apprehension, with or without any obvious cause, usually accompanied by autonomic disturbance, manifested by sympathetic over activity.

Symptoms are of sympathetic over activity.

Mild anxiety is common and needs no treatment. If symptoms become severe, interfering with normal routine of life, only then drugs are prescribed.

These are also known as minor tranquilizers.

Major tranquilizers are called neuroleptics.

Normal anxiety Pathological anxiety
Anxiolytics Neuroleptics
Same drug in smaller dose, acts as sedative5mg dose of diazepam to produce anti-anxiety effects and sleep Higher dose is required

 

Normal or physiological (Adaptive)

i.e. in interviews, examinations

Insomnia

Loss of sleep, deprivation of sleep. Varying from children (GH secretion) to elderly.

Normal adult requires 6-8 hours sleep.

Causes

–          Organic

–          Psychologic

–          Situational

Insomnia may be:

  1. Transient insomnia

Normal individual undergoing emotional disturbances (family, work, etc.) 1-2 doses of hypnotics are indicated to help cope with situation.

  1. Short term insomnia

Also related to emotional disturbances but may reoccur (psychiological disturbance) subjective to feeling. 5-10 day hypnotic with some missing doses.

As continuous use of hypnotics leads to:

  • Tolerance
  • Dependence
  • Rebound insomnia
  1. Chronic insomnia

Rarely benefited by hypnotics. Routine ingestion of hypnotics may produce mild dependence.

Underlying cause needs to be seen, whether psychiatric problem, depression or pain.

Insomnia secondary to underlying cause has to be treated, if pain analgesic is prescribed along with hypnotic.

Sedatives and hypnotics are not prescribed to children and elderly.

Children

Only sometimes given when someambolism (walking at night) occurs, involving hyperactive situations, night terrors, only if lack of sleep is detrimental.

Elderly

Unjustified use leads to greater risk of person becoming ataxic and confused. May produce rebound insomnia, especially if drug is discontinued suddenly.

 Management
1. Non – Pharmacological

–         Comfortable/conducive environment

–         Diet

–         Exercise

–         Stimulants like caffeine

–         Comfortable environment, milk (tryptophan has soothing effect)

–         Timing of sleep –fixed routine, better sleep habits

2. Pharmacological

Benzodiazepinessmall dose during day, higher dose at night,

Some tolerance does develop

Treatment of allied diseases

– Psychological

– Physical    

Sleep Disorders
  1. Difficulty in falling a sleep ( Latency)
  2. Interrupted Sleep (Frequent awakenings)
  3. Early Morning wakening
  4. Non- Refreshing sleep

Sedatives are also used in hypertension, for short term and also for bronchoscopy and diagnostic procedures.

Classification

Benzodiazepines
 Long Acting
    • Diazepam (Valium)
    • Flurazepam
    • Nitrazepam (Mogadon)
    • Quanezepam
    • Prazepam
    • Clonazepam (Pintril)
    • Chlorazepate (Tranxene)-prodrug
    • Chlordiazepoxide
    • Bromazepam (lexatonel)
Intermediate Acting
      •  Alprazolam (Xanax)
      •  Lorazepam (Ativan)
      •  oxazepam (Serax)
      •  Temazepam (Restoril)
Short Acting
      •  Midazolam (Versed)
      •  Triazolam (Halcion)
Non- Benzodiazepines

1. Imidazo pyridine derivative

Zolpidem –anti-anxiety

2. Pyrazolo pyrimidine Derivative

Zaleplon

3. Cyclo pyrrolone Derivatives

Eszopiclone, Zopiclone

4. Melatonin Receptor Agonist

Ramelteon

Barbiturates
Long Acting (10-12 hrs)

Phenobarbitone
Butabarbitone

Not preferred because of long hang overs

Intermediate Acting (6-8 hrs)

Allobarbitone

Amylobarbitone

Short Acting (3-6 hrs)

Pentobarbitone

Secobarbitone

Others
Chloral Derivatives

– Chloral hydrate –dental extraction in children
– Chloramethiazole

Carbamates

            – Meprobamate

Cyclic Ethers

Paraldehyde

Aliphatic Alcohols

– Ethanol

Miscellaneous

            – Hyoscine  

Antihistamines

Hydoxyzine

Diphenhydramine & Promethazine

Helpful in pruritis and allergic rhinitis.

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