secobarbital (Seconal)
Jump to navigation
Jump to search
Introduction
Tradename: Seconal. DEA-controlled substance: class 2.
Indications
- agitation
- insomnia
- general anesthesia, induction of sedation
- status epilepticus
- tetanus
- neuroprotection???
Contraindications
- absolute: barbiturate hypersensitivity
- relative
- breast feeding, children, CNS depression, depression, driving or operating machinery, elderly, hypotension, mental status changes, pain, porphyria, pregnancy, pulmonary disease, renal impairment, status asthmaticus, substance abuse, suicidal ideation
Dosage
Do not abruptly discontinue
Tabs: 100 mg.
Pharmacokinetics
- food interferes with absorption
- peak plasma levels reached in 2-4 hours after oral administration
- pharmacologic response within 15 minutes of oral dose
- duration of hypnotic effect
- 1-4 hours following oral dose
- 15 minutes following IV dose
- loses hypnotic effect after 2 weeks of administration
- protein binding 30-45%
- metabolism via liver to inactive metabolites
- eliminated in urine as metabolites & their glucuronide conjugates
- elimination 1/2life is about 30 hours
elimination via liver
1/2life = 19-34 hours
protein binding = 26-45 %
Adverse effects
- sedation
- respiratory arrest
- coma
- others
Drug interactions
- coadministration of valproic acid may increase plasma barbiturate levels
- barbiturates induce CYP1A2, CYP2C9 & CYP3A4
- may diminish levels of drugs metabolized by CYP1A2, CYP2C9 & CYP3A4
- secobarbital decreases acetaminophen effectiveness; may increase toxic metabolites with acetaminophen overdose
- valproate may inhibit metabolism of secobarbital
- most data for drug interactions is for phenobarbital
Laboratory
- specimen: serum; stable refrigerated or frozen
- methods: color, GLC, HPLC, RIA, EIA
- interferences: spectrophometric assay are subject to numerous interferences, but are useful emergency procedures
Mechanism of action
- suppresses seizure activity in cortex, thalamus & limbic system
- inhibition of both pre- & postsynaptic excitability
- protects brain from ischemia & intracranial pressure (high doses)
More general terms
Additional terms
- cytochrome p450 1A2 (cytochrome P3-450, phenacetin deethylase, cytochrome p450-4, CYP1A2)
- cytochrome P450 2C9; cytochrome P450 BP-1; cytochrome P450 MP-4; S-mephenytoin-4-hydroxylase; limonene 6-monooxygenase; limonene 7-monooxygenase (CYP2C9, CYP2C10)
- cytochrome P450 3A4 (cytochrome P450 C3, nifedipine oxidase, P450-PCN1, NF-25, CYP3A4)
Component of
References
- ↑ Clinical Guide to Laboratory Tests, 3rd edition, NW Tietz ed, WB Saunders, Philadelphia, 1995
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Clinical Guide to Laboratory Tests, NW Tietz (ed) 3rd ed, WB Saunders, Philadelpha 1995
- ↑ Prescriber's Letter 13(3): 2006 Cytochrome P450 drug interactions Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=220233&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ Harrison's Online, 2002