Secobarbital Sodium

Pronunciation: see-koe-BAR-bih-tahl SO-dee-uhm
Class: Sedative and hypnotic, Barbiturate

Trade Names

Seconal Sodium Pulvules
- Capsules 100 mg

Pharmacology

Depresses sensory cortex, decreases motor activity, alters cerebellar function, and produces drowsiness, sedation, and hypnosis.

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Pharmacokinetics

Absorption

Secobarbital absorption is rapid; the rate is increased if the sodium salt is ingested as a dilute solution or taken on an empty stomach.

Distribution

Secobarbital has very high lipid solubility and high protein binding. The drug is distributed to all tissues and fluids, with high concentrations in the brain, liver, and kidneys.

Metabolism

Metabolism of secobarbital is primarily by the hepatic microsomal enzyme system.

Elimination

Secobarbital is eliminated renally. The inactive metabolites are excreted as conjugates of glucuronic acid. The t ½ is 15 to 40 h (mean, 28 h).

Onset

Secobarbital's onset of action is 10 to 15 min (PO).

Duration

Secobarbital's duration of action is 3 to 4 h (PO).

Indications and Usage

Short-term (up to 2 wk) treatment of insomnia; induction of basal hypnosis before anesthesia (parenteral form); sedation (parenteral form).

Unlabeled Uses

Control of status epilepticus or acute seizure episodes.

Contraindications

Hypersensitivity to barbiturates; history of addiction to sedative/hypnotic drugs; history of porphyria; severe liver impairment; respiratory disease with dyspnea; nephritic patients.

Dosage and Administration

Insomnia
Adults

PO At bedtime 100 mg.

Hypnotic
Adults

IM 100 to 200 mg; IV 50 to 250 mg.

Sedation
Adults

PO 30 to 50 mg 3 or 4 times daily.

Children

PO/PR 2 to 6 mg/kg. For rectal administration, dilute to 1% to 1.5% solution.

Preoperative Sedation
Adults

PO 200 to 300 mg 1 to 2 h before surgery.

Children

PO 2 to 6 mg/kg (max, 100 mg) 1 to 2 h before surgery.

Sedation/Preanesthesia
Adults

IM (light sedation) 1 mg/kg 15 min before procedure.

Children

IM 4 to 5 mg/kg.

Convulsions
Adults

IM/IV 1.1 to 2.2 mg/kg. Max IV rate 50 mg/15 sec. Maximum adult IM dose 500 mg or 5 mL volume regardless of concentration.

Storage/Stability

Store oral preparation at room temperature. Refrigerate parenteral form. Use only clear solution; discard if precipitate forms or solution becomes cloudy.

Drug Interactions

Alcohol, CNS depressants

May produce additive CNS depressant effects.

Anticoagulants (eg, warfarin), beta blockers (eg, metoprolol, propranolol), verapamil, quinidine, theophyllines

May reduce activity of these drugs.

Anticonvulsants

May reduce serum concentrations of carbamazepine, valproic acid, and succinimides. Valproic acid may increase barbiturate serum levels.

Corticosteroids

May reduce effectiveness of corticosteroids.

Estrogens, estrogen-containing oral contraceptives

May reduce contraceptive effect and estrogen effect.

Laboratory Test Interactions

May increase bromsulphalein retention; may cause decreased serum bilirubin concentrations; false-positive phentolamine test results; decreased response to metyrapone; impaired absorption of radioactive cyanocobalamin.

Adverse Reactions

Cardiovascular

Bradycardia; hypotension; syncope.

CNS

Drowsiness; agitation; confusion; headache; hyperkinesia; ataxia; CNS depression; paradoxical excitement; nightmares; psychiatric disturbances; hallucinations; insomnia; dizziness.

GI

Nausea; vomiting; constipation.

Hematologic

Blood dyscrasias (eg, agranulocytosis, thrombocytopenia).

Respiratory

Hypoventilation; apnea; laryngospasm; bronchospasm.

Miscellaneous

Hypersensitivity reactions (eg, angioedema, rashes, exfoliative dermatitis); fever; liver damage; injection site reactions (eg, local pain, thrombophlebitis).

Precautions

Monitor

Obtain baseline Hct, Hgb, RBC, and LFT results (transaminase levels and bilirubin). Periodically evaluate those results if patient is on long-term therapy.


Pregnancy

Category D .

Lactation

Excreted in breast milk.

Children

May respond with excitement rather than depression.

Elderly

More sensitive to drug effects; dosage reduction is required.

Renal Function

Use drug with caution; dosage reduction may be required.

Hepatic Function

Use drug with caution; dosage reduction may be required.

Dependence

Tolerance or psychological and physical dependence may occur with continued use.

IV administration

Do not exceed maximum IV rate 50 mg/15 sec; respiratory depression, apnea, and hypotension may result. Parenteral solutions are highly alkaline; extravasation may cause tissue damage and necrosis. Inadvertent intraarterial injection may lead to arterial spasm, thrombosis and gangrene.

Seizure disorders

Status epilepticus may result from abrupt discontinuation.

Overdosage

Symptoms

CNS and respiratory depression, Cheyne-Stokes respiration, areflexia, oliguria, tachycardia, hypotension, lowered body temperature, coma, pulmonary edema, death.

Patient Information

  • Explain that this medication may cause psychological and physical dependence. Emphasize that it is important not to increase dose without consulting health care provider.
  • Discuss ways to facilitate sleep (quiet, darkened room; avoidance of caffeine and nicotine; warm bath, warm milk; deep breathing; relaxation; self-hypnosis).
  • Inform patient that it may take a few doses to achieve noticeable sleep benefit.
  • Instruct patient to notify health care provider immediately of sudden onset of fever, sore throat, bruising, rash, jaundice, or unusual bleeding (eg, epistaxis).
  • Instruct patient to avoid intake of alcoholic beverages or other CNS depressants (eg, pain relievers, antihistamines, sedatives) to prevent serious CNS depression.
  • Emphasize importance of follow-up evaluation with health care provider to monitor progress of therapy.
  • Inform patient that after discontinuation of drug, nighttime sleeping might be disturbed for a few days and increased dreaming may occur.
  • Advise patient that drug may cause daytime drowsiness and to use caution while driving or performing other tasks requiring mental alertness.
  • Instruct patient not to discontinue medication abruptly without consulting health care provider.

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