butabarbital (Rx)

1-10%

Somnolence

<1%

Abnormal thinking

Agitation

Anxiety

Apnea

Ataxia

Bradycardia

CNS depression

Confusion

Constipation

Dizziness

Fever

Hallucination

Headache

Hepatotoxicity

Hypersensitivity rxn

Hypoventilation

Insomnia

Nausea

Nervousness

Nightmares

Psychiatric disturbance

Vomiting

Contraindications

Barbiturate or tartrazine sensitivity, liver disease, severe respiratory disease, porphyria

Cautions

Because sleep disturbances may be the presenting manifestation of a physical and/or psychiatric disorder, symptomatic treatment of insomnia should be initiated only after a careful evaluation of patient; failure of insomnia to remit after 7 to 10 days of treatment may indicate presence of a primary psychiatric and/or medical illness that should be evaluated

Worsening of insomnia or emergence of new thinking or behavior abnormalities may be the consequences of an unrecognized psychiatric or physical disorder; it is important to use smallest possible effective dose, especially in the elderly

Complex behaviors such as “sleep driving” (i.e., driving while not fully awake after ingestion of a sedative-hypnotic, with amnesia for event) reported; events can occur in sedative-hypnotic-naive as well as in sedative-hypnotic-experienced persons; the use of alcohol and other CNS depressants with sedative-hypnotics appears to increase risk of such behaviors, as does the use of sedative-hypnotics at doses exceeding the maximum recommended dose; due to risk to patient and community, discontinuation of sedative-hypnotics should be strongly considered for patients who report a “sleep driving” episode

Other complex behaviors (e.g., preparing and eating food, making phone calls, or having sex) reported in patients who are not fully awake after taking a sedative-hypnotic; patients usually do not remember these events

Because drug can cause drowsiness and a decreased level of consciousness, patients, particularly the elderly, are at a higher risk of falls

Rare cases of angioedema involving tongue, glottis or larynx reported; some patients have had additional symptoms such as dyspnea, throat closing, or nausea and vomiting that suggest anaphylaxis; if angioedema involves tongue, glottis or larynx, airway obstruction may occur and be fatal; patients who develop angioedema with sedative-hypnotics should not be rechallenged with drug

Barbiturates may be habit forming; tolerance, psychological and physical dependence may occur with continued use; to minimize possibility of overdosage or development of dependence, prescribing and dispensing of sedative-hypnotic barbiturates should be limited to amount required for interval until next appointment; abrupt cessation after prolonged use in dependent person may result in withdrawal symptoms, including delirium, convulsions, and possibly death; withdraw barbiturates gradually from patient known to be taking excessive dosage over long periods of time

Use caution when barbiturates are administered to patients with acute or chronic pain; paradoxical excitement could be induced, or important symptoms could be masked; however, use of barbiturates as sedatives in postoperative surgical period, and as adjuncts to cancer chemotherapy, is well established

Administer with caution, if at all, to patients who are mentally depressed, have suicidal tendencies, or a history of drug abuse

Elderly or debilitated patients may react to barbiturates with marked excitement, depression, and confusion; in some persons, barbiturates repeatedly produce excitement rather than depression

In patients with hepatic damage, barbiturates should be administered with caution and initially in reduced doses; drug should not be administered to patients showing the premonitory signs of hepatic coma

Pregnancy

Barbiturates can cause fetal damage when administered to a pregnant woman; retrospective, case-controlled studies have suggested a connection between maternal consumption of barbiturates and a higher than expected incidence of fetal abnormalities; following oral administration, barbiturates readily cross placental barrier and are distributed throughout fetal tissues with highest concentrations found in placenta, fetal liver, and brain

Withdrawal symptoms occur in infants born to mothers who receive barbiturates throughout last trimester of pregnancy; if drug is used during pregnancy, or if patient becomes pregnant while taking this drug, apprise patient of the potential hazard to fetus

Infants suffering from long-term barbiturate exposure in utero may have an acute withdrawal syndrome of seizures and hyperirritability from birth to a delayed onset of up to 14 days

Labor and delivery

• Hypnotic doses of barbiturates do not appear to significantly impair uterine activity during labor; administration of sedative-hypnotic barbiturates to mother during labor may result in respiratory depression in newborn; premature infants are particularly susceptible to depressant effects of barbiturates; if barbiturates are used during labor and delivery, resuscitation equipment should be available

Lactation

Caution should be exercised when a barbiturate is administered to a nursing woman since small amounts of some barbiturates are excreted in the milk

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Interferes with transmission of impulses from the thalamus to the cortex; depresses sensory cortex & decreases motor activity

Pharmacokinetics

Half-Life: ~100 hr

Duration: 6-8 hr

Onset: 45-60 min

Enzymes induced: CYP1A2, CYP2C9/10, CYP3A4

Excretion: Urine