CNS Pharmacology - Definitions



Definitions

General anaesthesia
General anaesthesia are drugs that produce a general non-selective reversible depression of the CNS involving loss of consciousness, analgesia, relaxation of voluntary muscles and suppression of reflex activity. Eg: Barbiturates

Dissociative anaesthetics
These are drugs that produce a state of CNS depression that is characterized by a feeling of dissociation from surroundings, unconsciousness and analgesia but with little or no muscle relaxation. Eg: Ketamine

Anxiolytics
These are the drugs that abolish or relieve feelings of anxiety. Eg: Alprazolam

Tranquillizers/Ataractics/Neuroleptics
·         These drugs exert quietening, calming effects on animals, lessening anxiety and sometimes reducing fear and aggression in animal species with naturally viscous or nervous temperaments.  
·         They may be used to facilitate the handling of animals and as premedicants.
·         Do not produce loss of consciousness even at dose rates above the therapeutic range.
·         Eg: Acepromazine

Sedative hypnotics
These are drugs which depress the CNS sufficiently to cause lethargy, drowsiness and indifference to the surroundings. They decrease locomotor activity. They allay fear and apprehension, but the animal remains conscious, when normal clinical dose rates are used. Eg: Xylazine

Hypnotics
Agents that induce and/or maintain a state of sleep from which the recipient can be easily aroused.
Eg: Zolpidem

Centrally acting muscle relaxant
These are the agents that produce flaccid relaxation of skeletal muscles, by their action at spinal level without loss. Eg: Guaiphenesin

Anticonvulsant
These are CNS depressant, whose primary action is an ability to suppress convulsions arising from CNS stimulants.
Eg: Phenytoin

Neuroleptanalgesia
It is a state of altered CNS activity produced by the combined administration of a neuroleptic and narcotic analgesics of the morphine type.
Eg: Fentanyl + Droperidol

Antidepressant / thymoleptics
These drugs produce mild stimulation of higher centers but do not cause symptoms of marked hyper excitability even at high dose levels. Eg: Imipramine

Medullary stimulants / Analeptics
These drugs stimulate some medullary centers, including the respiratory centre. Eg: Doxaparm

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