APROBARBITAL
(a-pro-bar'bi-tol)
Alurate
Classifications: central nervous system agent; anxiolytic, sedative-hypnotic; barbiturate
Prototype: Secobarbital
Pregnancy Category: D

Availability

40 mg/5 mL elixir

Actions

Intermediate-acting barbiturate. These agents depress the sensory cortex, decrease motor activity, alter cerebellar function, and produce drowsiness, sedation, and hypnosis. Barbiturates have little analgesic action at subanesthetic doses and may increase the reaction to painful stimuli. All barbiturates exhibit anticonvulsant activity in anesthetic doses.

Therapeutic Effects

Barbiturates can produce all levels of CNS mood alteration, from excitation to mild sedation, hypnosis, and deep coma. Barbiturates are respiratory depressants; the degree of respiratory depression is dose dependent. With hypnotic doses, respiratory depression is similar to that which occurs during physiologic sleep.

Uses

Indicated for routine sedation and as a hypnotic in the short-term treatment of insomnia for up to 2 wk. Barbiturates seem to lose their efficacy for sleep induction and maintenance after this period of time.

Contraindications

Barbiturate hypersensitivity; history of manifest or latent porphyria; impaired liver function; impaired renal function; severe respiratory distress, respiratory disease where dyspnea, obstruction, or cor pulmonale is present; previous addiction to the sedative-hypnotic group; acute or chronic pain. Safety during pregnancy (category D), lactation, or in children is not established.

Cautious Use

Older adults or debilitated patients, presence of fever, hyperthyroidism, diabetes mellitus, severe anemia, debility, severely impaired liver function, pulmonary or cardiac disease, status asthmaticus, shock, uremia, borderline hypoadrenal function.

Route & Dosage

Sedative
Adult: PO 40 mg t.i.d.

Hypnotic
Adult: PO 40–160 mg

Administration

Oral

Adverse Effects (1%)

CNS: Somnolence, agitation, confusion, hyperkinesia, ataxia, vertigo, CNS depression, nightmares, lethargy, residual sedation (hangover effect), paradoxical excitement, nervousness, psychiatric disturbance, hallucinations, insomnia, anxiety, dizziness, thinking abnormalities, delirium and stupor with excessive amounts. CV: Bradycardia, circulatory collapse, hypotension, syncope. GI: Nausea, vomiting, constipation, diarrhea, epigastric pain. Hematologic: Agranulocytosis (rare). Respiratory: Hypoventilation, apnea, respiratory depression, laryngospasm, bronchospasm.

Diagnostic Test Interference

barbiturates may cause a false-positive phentolamine test and decrease serum bilirubin concentrations.

Interactions

Drug: cns depressants, alcohol, sedatives compound CNS depression; mao inhibitors cause excessive CNS depression; anticonvulsants, rifampin, phenmetrazine may decrease effects of aprobarbital. Herbal: Kava-kava, valerian may potentiate sedation.

Pharmacokinetics

Absorption: Well absorbed from GI tract. Onset: 45–60 min. Duration: 3 h. Distribution: Crosses placenta; distributed into breast milk. Metabolism: Metabolized in the liver. Elimination: Excreted in urine. Half-Life: 14–40 h.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug