FDA label 34657a11-a39c-6e5f-e054-00144ff88e88

WARNINGS Habit Forming — Amobarbital sodium may be habit forming. Tolerance, psychological and physical dependence may occur with continued use ( see Drug Abuse and Dependence and Pharmacokinetics under Clinical Pharmacology ). Patients who have psychological dependence on barbiturates may increase the dosage or decrease the dosage interval without consulting a physician and may subsequently develop a physical dependence on barbiturates. In order to minimize the possibility of overdosage or the development of dependence, the prescribing and dispensing of sedative-hypnotic barbiturates should be limited to the amount required for the interval until the next appointment. Abrupt cessation after prolonged use in a person who is dependent on the drug may result in withdrawal symptoms, including delirium, convulsions, and possibly death. Barbiturates should be withdrawn gradually from any patient known to be taking excessive doses over long periods of time ( see Drug Abuse and Dependence ). Intravenous Administration — Too rapid administration may cause respiratory depression, apnea, laryngo- spasm, or vasodilation with fall in blood pressure. Acute or Chronic Pain — Caution should be exercised when barbiturates are administered to patients with acute or chronic pain, because paradoxical excitement could be induced or important symptoms could be masked. However, the use of barbiturates as sedatives in the postoperative surgical period and as adjuncts to cancer chemotherapy is well established. Usage in Pregnancy — Barbiturates can cause fetal damage when administered to a pregnant woman. Retrospective, case-controlled studies have suggested a connection between the maternal consumption of barbiturates and a higher than expected incidence of fetal abnormalities. Barbiturates readily cross the placental barrier and are distributed throughout fetal tissues; the highest concentrations are found in the placenta, fetal liver, and brain. Fetal blood levels approach maternal blood levels following parenteral administration. Withdrawal symptoms occur in infants born to women who receive barbiturates throughout the last trimester of pregnancy ( see Drug Abuse and Dependence ). If amobarbital sodium is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus. Synergistic Effects — The concomitant use of alcohol or other CNS depressants may produce additive CNS- depressant effects.

ADVERSE REACTIONS The following adverse reactions and their incidence were compiled from surveillance of thousands of hospitalized patients who received barbiturates. Because such patients may be less aware of certain of the milder adverse effects of barbiturates, the incidence of these reactions may be somewhat higher in fully ambulatory patients. More than 1 in 100 P atients The most common adverse reaction, estimated to occur at a rate of 1 to 3 patients per 100, is the following: Nervous System: Somnolence Less than 1 in 100 P atients Adverse reactions estimated to occur at a rate of less than 1 in 100 patients are listed below, grouped by organ system and by decreasing order of occurrence: Nervous System: Agitation, confusion, hyperkinesia, ataxia, CNS depression, nightmares, nervousness, psychiatric disturbance, hallucinations, insomnia, anxiety, dizziness, abnormality in thinking Respiratory System: Hypoventilation, apnea, postoperative atelectasis Cardiovascular System: Bradycardia, hypotension, syncope Digestive System: Nausea, vomiting, constipation Other Reported Reactions: Headache, injection site reactions, hypersensitivity reactions (angioedema, skin rashes, exfoliative dermatitis), fever, liver damage, megaloblastic anemia following chronic phenobarbital use