CNS barbiturates

CNS Barbiturates produce depression of central nervous system in dose dependent manner. In small dose, barbiturates relieve anxiety and are generally used as sedative. In hypnotic dose, it produces sleep resembling normal physiological sleep. Hypnotic dose of barbiturates produce motor incoordination. 

Barbiturates are thought to interfere with sodium and potassium transport across cell membranes. This leads to inhibition of the mesencephalic reticular activating system. Polysynaptic transmission is inhibited in all areas of the CNS. Barbiturates also potentiate GABA action on chloride entry into the neuron, although they do not bind at the benzodiazepine receptor. 

CNS Barbiturates cause drowsiness, impaired concentration, and mental and physical sluggishness. 

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