Indication |
For short-term treatment of insomnia and anxiety disorders |
Pharmacodynamics |
Butabarbital, a barbiturate, is used for the treatment of short
term insomnia. It belongs to a group of medicines called central nervous
system (CNS) depressants that induce drowsiness and relieve tension or
nervousness. Little analgesia is conferred by barbiturates; their use in
the presence of pain may result in excitation. |
Mechanism of action |
Butabarbital binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl-
ionopore is open. The post-synaptic inhibitory effect of GABA in the
thalamus is, therefore, prolonged. All of these effects are associated
with marked decreases in GABA-sensitive neuronal calcium conductance
(gCa). The net result of barbiturate action is acute potentiation of
inhibitory GABAergic tone. Barbiturates also act through potent (if less
well characterized) and direct inhibition of excitatory AMPA-type
glutamate receptors, resulting in a profound suppression of
glutamatergic neurotransmission. |
Absorption |
Not Available |
Volume of distribution |
Not Available |
Protein binding |
Not Available |
Metabolism |
Not Available |
Route of elimination |
Barbiturates are metabolized primarily by the hepatic microsomal
enzyme system, and most metabolic products are excreted in the urine. |
Half life |
Not Available |
Clearance |
Not Available |
Toxicity |
Signs of overdose include confusion (severe), decrease in or loss
of reflexes, drowsiness (severe), fever, irritability (continuing), low
body temperature, poor judgment, shortness of breath or slow or troubled
breathing, slow heartbeat, slurred speech, staggering, trouble in
sleeping, unusual movements of the eyes, weakness (severe). |
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