| Item |
Information |
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Drug Groups
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approved |
|
Description
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A barbituric acid derivative that acts as a nonselective central nervous system depressant. It promotes binding to inhibitory gamma-aminobutyric acid subtype receptors, and modulates chloride currents through receptor channels. It also inhibits glutamate induced depolarizations. [PubChem] |
| Indication |
For the treatment of all types of seizures except absence seizures. |
| Pharmacology |
Phenobarbital, the longest-acting barbiturate, is used for its anticonvulsant and sedative-hypnotic properties in the management of all seizure disorders except absence (petit mal). |
| Toxicity |
CNS and respiratory depression which may progress to Cheyne-Stokes respiration, areflexia, constriction of the pupils to a slight degree (though in severe poisoning they may wshow paralytic dilation), oliguria, tachycardia, hypotension, lowered body temperature, and coma. Typical shock syndrome (apnea, circulatory collapse, respiratory arrest, and death) may occur. |
| Affected Organisms |
| • |
Humans and other mammals |
|
| Biotransformation |
Hepatic (mostly via CYP2C19). |
| Absorption |
Absorbed in varying degrees following oral, rectal or parenteral administration. The salts are more rapidly absorbed than are the acids. The rate of absorption is increased if the sodium salt is ingested as a dilute solution or taken on an empty stomach. |
| Half Life |
53 to 118 hours (mean 79 hours) |
| Protein Binding |
20 to 45% |
| References |
| • |
Kwan P, Brodie MJ: Phenobarbital for the treatment of epilepsy in the 21st century: a critical review. Epilepsia. 2004 Sep;45(9):1141-9.
[Pubmed]
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| • |
Taylor S, Tudur Smith C, Williamson PR, Marson AG: Phenobarbitone versus phenytoin monotherapy for partial onset seizures and generalized onset tonic-clonic seizures. Cochrane Database Syst Rev. 2001;(4):CD002217.
[Pubmed]
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| • |
Tudur Smith C, Marson AG, Williamson PR: Carbamazepine versus phenobarbitone monotherapy for epilepsy. Cochrane Database Syst Rev. 2003;(1):CD001904.
[Pubmed]
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| • |
Kalviainen R, Eriksson K, Parviainen I: Refractory generalised convulsive status epilepticus : a guide to treatment. CNS Drugs. 2005;19(9):759-68.
[Pubmed]
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| • |
Booth D, Evans DJ: Anticonvulsants for neonates with seizures. Cochrane Database Syst Rev. 2004 Oct 18;(4):CD004218.
[Pubmed]
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| External Links |
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