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Pronunciation
(see koe BAR bi tal)
Generic Available (U.S.)
No
Index Terms
Controlled Substance
C-II
Brand Names: U.S.
Pharmacologic Category
Use: Labeled Indications
Preanesthetic agent; short-term treatment of insomnia
Pregnancy Risk Factor
D
Pregnancy Considerations
Barbiturates can be detected in the placenta, fetal liver, and fetal brain. Fetal and maternal blood concentrations may be similar following parenteral administration. An increased incidence of fetal abnormalities may occur following maternal use. When used during the third trimester of pregnancy, withdrawal symptoms may occur in the neonate including seizures and hyperirritability; symptoms may be delayed up to 14 days. Use during labor does not impair uterine activity; however, respiratory depression may occur in the newborn; resuscitation equipment should be available, especially for premature infants.
Lactation
Enters breast milk/use caution (AAP rates “compatible”; AAP 2001 update pending)
Breast-Feeding Considerations
Small amounts of barbiturates are found in breast milk.
Contraindications
Hypersensitivity to barbiturates or any component of the formulation; marked hepatic impairment; dyspnea or airway obstruction; porphyria; pregnancy
Warnings/Precautions
Concerns related to adverse effects:
• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).
• Hypersensitivity reactions: Postmarketing studies have indicated that the use of hypnotic/sedative agents for sleep has been associated with hypersensitivity reactions including anaphylaxis as well as angioedema.
• Paradoxical responses: May cause paradoxical responses, including agitation and hyperactivity, particularly in acute pain, chronic pain and pediatric patients.
• Sleep-related activities: An increased risk for hazardous sleep-related activities such as sleep-driving; cooking and eating food, and making phone calls while asleep have also been noted. Discontinue treatment in patients who report a sleep-driving episode.
Disease-related concerns:
• Cardiovascular disease: Use with caution in patients with cardiovascular disease; may cause hypotension.
• Depression: Use with caution in patients with depression or suicidal tendencies.
• Drug abuse: Use with caution in patients with a history of drug abuse or acute alcoholism; potential for drug dependency exists. Tolerance, psychological and physical dependence may occur with prolonged use.
• Hepatic impairment: Use with caution in patients with hepatic impairment.
• Renal impairment: Use with caution in patients with renal impairment.
• Respiratory disease: Use with caution in patients with respiratory disease; may cause respiratory depression.
Concurrent drug therapy issues:
• Sedatives: Effects may be potentiated when used with other sedative drugs or ethanol.
Special populations:
• Elderly: Use with caution in the elderly; closely monitor elderly or debilitated patients for impaired cognitive or motor performance. May be inappropriate in this age group due to increased risk for adverse effects and high addiction potential (Beers Criteria).
• Pediatrics: Use with caution in children.
Other warnings/precautions:
• Appropriate use: Symptomatic treatment of insomnia should be initiated only after careful evaluation of potential causes of sleep disturbance. Failure of sleep disturbance to resolve after 7-10 days may indicate psychiatric and/or medical illness.
• Withdrawal: Abrupt cessation may precipitate withdrawal, including status epilepticus in epileptic patients.
Adverse Reactions
Frequency not defined.
Cardiovascular: Hypotension
Central nervous system: Dizziness, lightheadedness, “hangover” effect, drowsiness, CNS depression, fever, confusion, mental depression, unusual excitement, nervousness, faint feeling, headache, insomnia, nightmares, hallucinations
Dermatologic: Exfoliative dermatitis, rash, Stevens-Johnson syndrome
Gastrointestinal: Nausea, vomiting, constipation
Hematologic: Agranulocytosis, megaloblastic anemia, thrombocytopenia, thrombophlebitis, urticaria
Local: Pain at injection site
Respiratory: Apnea, laryngospasm, respiratory depression
Postmarketing and/or case reports: Anaphylaxis, angioedema, complex sleep-related behavior (sleep-driving, cooking or eating food, making phone calls)
Metabolism/Transport Effects
Induces CYP2A6 (strong), CYP2C8 (strong), CYP2C9 (strong)
Drug Interactions
Acetaminophen: Barbiturates may increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Risk C: Monitor therapy
Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Risk C: Monitor therapy
Beta-Blockers: Barbiturates may decrease the serum concentration of Beta-Blockers. Exceptions: Atenolol; Levobunolol; Metipranolol; Nadolol. Risk C: Monitor therapy
Calcium Channel Blockers: Barbiturates may increase the metabolism of Calcium Channel Blockers. Management: Monitor for decreased therapeutic effects of calcium channel blockers with concomitant barbiturate therapy. Calcium channel blocker dose adjustments may be necessary. Nimodipine Canadian labeling contraindicates concomitant use with phenobarbital. Exceptions: Clevidipine. Risk C: Monitor therapy
Chloramphenicol: Barbiturates may increase the metabolism of Chloramphenicol. Chloramphenicol may decrease the metabolism of Barbiturates. Risk D: Consider therapy modification
CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Exceptions: Levocabastine (Nasal). Risk C: Monitor therapy
Contraceptives (Estrogens): Barbiturates may diminish the therapeutic effect of Contraceptives (Estrogens). Contraceptive failure is possible. Management: Use of a non-hormonal contraceptive is recommended. Risk D: Consider therapy modification
Contraceptives (Progestins): Barbiturates may diminish the therapeutic effect of Contraceptives (Progestins). Contraceptive failure is possible. Management: Use of alternative, nonhormonal contraceptives is recommended. Risk D: Consider therapy modification
Corticosteroids (Systemic): Barbiturates may decrease the serum concentration of Corticosteroids (Systemic). Risk C: Monitor therapy
CycloSPORINE: Barbiturates may increase the metabolism of CycloSPORINE. Risk D: Consider therapy modification
CycloSPORINE (Systemic): Barbiturates may increase the metabolism of CycloSPORINE (Systemic). Risk D: Consider therapy modification
CYP2A6 Substrates: CYP2A6 Inducers (Strong) may increase the metabolism of CYP2A6 Substrates. Risk C: Monitor therapy
CYP2C8 Substrates: CYP2C8 Inducers (Strong) may increase the metabolism of CYP2C8 Substrates. Risk C: Monitor therapy
CYP2C9 Substrates: CYP2C9 Inducers (Strong) may increase the metabolism of CYP2C9 Substrates. Risk C: Monitor therapy
Diclofenac: CYP2C9 Inducers (Strong) may decrease the serum concentration of Diclofenac. Risk C: Monitor therapy
Disopyramide: Barbiturates may increase the metabolism of Disopyramide. Risk C: Monitor therapy
Divalproex: May decrease the metabolism of Barbiturates. Barbiturates may decrease the serum concentration of Divalproex. Risk C: Monitor therapy
Doxycycline: Barbiturates may decrease the serum concentration of Doxycycline. Risk D: Consider therapy modification
Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (e.g., opioids, barbiturates) with concomitant use. Risk D: Consider therapy modification
Etoposide: Barbiturates may decrease the serum concentration of Etoposide. Risk C: Monitor therapy
Etoposide Phosphate: Barbiturates may decrease the serum concentration of Etoposide Phosphate. Barbiturates may increase the metabolism, via CYP isoenzymes, of etoposide phosphate. Risk C: Monitor therapy
Felbamate: Barbiturates may decrease the serum concentration of Felbamate. Felbamate may increase the serum concentration of Barbiturates. Management: Monitor for elevated barbiturate concentrations/toxicity if felbamate is initiated/dose increased, or reduced concentrations/effects if felbamate is discontinued/dose decreased. Refer to phenobarbital dosing guidelines for patients receiving that agent. Risk C: Monitor therapy
Fosphenytoin: Barbiturates may decrease the serum concentration of Fosphenytoin. Risk C: Monitor therapy
Griseofulvin: Barbiturates may decrease the serum concentration of Griseofulvin. Risk C: Monitor therapy
HydrOXYzine: May enhance the CNS depressant effect of Barbiturates. Management: Consider a decrease in the barbiturate dose, as appropriate, when used together with hydroxyzine. With concurrent use, monitor patients closely for excessive response to the combination. Risk D: Consider therapy modification
LamoTRIgine: Barbiturates may decrease the serum concentration of LamoTRIgine. Management: See lamotrigine prescribing information for specific age-dependent dosing guidelines regarding concurrent use with a barbiturate, as well as for adjusting lamotrigine dosing if concurrent barbiturate therapy is discontinued. Risk D: Consider therapy modification
Meperidine: Barbiturates may enhance the CNS depressant effect of Meperidine. Barbiturates may increase serum concentrations of the active metabolite(s) of Meperidine. Risk C: Monitor therapy
Methadone: Barbiturates may decrease the serum concentration of Methadone. Risk C: Monitor therapy
Phenytoin: Barbiturates may decrease the serum concentration of Phenytoin. Risk C: Monitor therapy
Primidone: May enhance the adverse/toxic effect of Barbiturates. Primidone is converted to phenobarbital, and thus becomes additive with existing barbiturate therapy. Risk C: Monitor therapy
Propafenone: Barbiturates may decrease the serum concentration of Propafenone. Risk C: Monitor therapy
Pyridoxine: May increase the metabolism of Barbiturates. Apparent in high pyridoxine doses (eg, 200 mg/day) Risk C: Monitor therapy
QuiNIDine: Barbiturates may enhance the hepatotoxic effect of QuiNIDine. Barbiturates may decrease the serum concentration of QuiNIDine. Risk C: Monitor therapy
Rifamycin Derivatives: May increase the metabolism of Barbiturates. Risk C: Monitor therapy
Selective Serotonin Reuptake Inhibitors: CNS Depressants may enhance the adverse/toxic effect of Selective Serotonin Reuptake Inhibitors. Specifically, the risk of psychomotor impairment may be enhanced. Risk C: Monitor therapy
Teniposide: Barbiturates may decrease the serum concentration of Teniposide. Management: Consider alternatives to combined treatment with barbiturates and teniposide due to the potential for decreased teniposide concentrations. If the combination cannot be avoided, monitor teniposide response closely. Risk D: Consider therapy modification
Theophylline Derivatives: Barbiturates may decrease the serum concentration of Theophylline Derivatives. Exceptions: Dyphylline. Risk C: Monitor therapy
Thiazide Diuretics: Barbiturates may enhance the orthostatic hypotensive effect of Thiazide Diuretics. Risk C: Monitor therapy
Treprostinil: CYP2C8 Inducers (Strong) may decrease the serum concentration of Treprostinil. Risk C: Monitor therapy
Tricyclic Antidepressants: Barbiturates may increase the metabolism of Tricyclic Antidepressants. Risk D: Consider therapy modification
Valproic Acid: May decrease the metabolism of Barbiturates. Barbiturates may decrease the serum concentration of Valproic Acid. Risk C: Monitor therapy
Vitamin K Antagonists (eg, warfarin): Barbiturates may increase the metabolism of Vitamin K Antagonists. Risk D: Consider therapy modification
Ethanol/Nutrition/Herb Interactions
Ethanol: May increase CNS depression; monitor for increased effects with coadministration. Caution patients about effects.
Herb/Nutraceutical: Avoid valerian, St John's wort, kava kava, gotu kola (may increase CNS depression).
Mechanism of Action
Depresses CNS activity by binding to barbiturate site at GABA-receptor complex enhancing GABA activity, depressing reticular activity system; higher doses may be gabamimetic
Pharmacodynamics/Kinetics
Onset of hypnosis: 15-30 minutes
Duration: 3-4 hours with 100 mg dose
Distribution: 1.5 L/kg
Protein binding: 45% to 60%
Metabolism: Hepatic, by microsomal enzyme system
Half-life elimination: 15-40 hours, mean: 28 hours
Time to peak, serum: Within 2-4 hours
Excretion: Urine (as inactive metabolites, small amounts as unchanged drug)
Dosage
Oral:
Children:
Preoperative sedation: 2-6 mg/kg (maximum dose: 100 mg/dose) 1-2 hours before procedure
Sedation: 6 mg/kg/day divided every 8 hours
Adults:
Hypnotic: Usual: 100 mg/dose at bedtime; range: 100-200 mg/dose
Preoperative sedation: 100-300 mg 1-2 hours before procedure
Monitoring Parameters
Blood pressure, heart rate, respiratory rate, CNS status
Patient Education
Drug may cause physical and/or psychological dependence. While using this medication, do not use alcohol. Maintain adequate hydration, unless instructed to restrict fluid intake. You may experience drowsiness, dizziness, blurred vision, nausea, vomiting, or constipation. Report skin rash or irritation; CNS changes (confusion, depression, increased sedation, excitation, headache, insomnia, or nightmares); respiratory difficulty or shortness of breath; difficulty swallowing or feeling of tightness in throat; unusual weakness; unusual bleeding in mouth, urine, or stool; or unusual swelling, especially on face or neck.
Geriatric Considerations
Use of this agent in the elderly is not recommended due to its long half-life and addiction potential.
This medication is considered to be potentially inappropriate in this patient population (Beers Criteria severity: High).
Dental Health: Effects on Dental Treatment
No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Comment
In 2007, the FDA requested that all manufacturers of sedative-hypnotic drug products revise labeling to include a greater emphasis on the risks of adverse effects. These risks include severe allergic reactions (anaphylaxis, angioedema) and complex sleep-related behaviors, which may include sleep-driving (driving while not fully awake and with no memory of the event), making phone calls, and preparing and eating food while asleep.
Nursing: Physical Assessment/Monitoring
Assess patient for history of addiction; long-term use can result in dependence, abuse, or tolerance. Assess for CNS depression, abnormal thinking, and behavior changes. Monitor vital signs and respiratory status. After long-term use, taper dosage slowly when discontinuing. For inpatient use, institute safety measures.
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, oral, as sodium:
Seconal®: 100 mg
Pricing: U.S. (www.drugstore.com)
Capsules (Seconal)
100 mg (20): $233.98
References
American Academy of Pediatrics Committee on Drugs, "Transfer of Drugs and Other Chemicals Into Human Milk," Pediatrics, 2001, 108(3):776-89.
Levine HL, Cohen ME, Duffner PK, et al, “Rectal Absorption and Disposition of Secobarbital in Epileptic Children,” Pediatr Pharmacol (New York), 1982, 2(1):33-8.
Monteil RA, Raybaud H, Madinier I, et al, “Occurrence of Oral Mucosal Necrosis in a Patient With Barbiturate-Induced Coma,” Oral Surg Oral Med Oral Pathol, 1991, 72(5):562-4.
Nahata MC, Starling S, and Edwards RC, “Prolonged Sedation Associated With Secobarbital in Newborn Infants Receiving Ventilatory Support,” Am J Perinatol, 1991, 8(1):35-6.
Tracqui A, Kintz P, Mangin P, et al, “A Fatality Involving Secobarbital, Nitrazepam, and Codeine,” Am J Forensic Med Pathol, 1989, 10(2):130-3.
Wolfert RR and Cox RM, “Room Temperature Stability of Drug Products Labeled for Refrigerated Storage,” Am J Hosp Pharm, 1975, 32(6):585-7.
International Brand Names
Lexi-Comp.com
Last full review/revision January 2012
Content last modified January 2012
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