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It is generally agreed that respiratory depression or arrest due to unusual sensitivity to thiopental sodium or overdosage is easily managed if there is no concomitant respiratory obstruction. If the airway is patent, any method of ventilating the lungs (that prevents hypoxia) should be successful in maintaining other vital functions. Since depression of respiratory activity is one of the characteristic actions of the drug, it is important to observe respiration closely. Should laryngeal spasm occur, it may be relieved by one of the usual methods, such as the use of a relaxant drug or positive pressure oxygen. Endotracheal intubation may be indicated in difficult cases. (L1712)

Therapeutic effects of acetaminophen may be decreased when the medication is used concurrently in patients receiving chronic barbiturate therapy because of increased metabolism resulting from induction of hepatic microsomal enzymes; risk of hepatotoxicity with single toxic doses or prolonged use of high doses of acetaminophen may be increased in alcoholics or in patients regularly using hepatic enzyme inducers such as barbiturates. /Barbiturates/

Concurrent use with barbiturates may result in increased metabolism, leading to decreased serum concentrations and reduced elimination half-lives of carbamazepine or succinimide anticonvulsants because of induction of hepatic microsomal enzyme activity. Monitoring of serum concentrations as a guide to dosage is recommended, especially when carbamazepine or a succinimide anticonvulsant is added to or withdrawn from an existing regimen. /Barbiturates/

Concurrent use with barbiturates, especially phenobarbital, may induce microsomal metabolism to increase formation of alkylating metabolites of cyclophosphamide, thereby reducing the half-life and increasing the leukopenic activity of cyclophosphamide. /Barbiturates/

Concurrent use with barbiturates, especially phenobarbital, may reduce serum disopyramide to ineffective concentrations; therefore, monitoring of its serum concentrations is necessary during concurrent therapy. /Barbiturates/

For more Interactions (Complete) data for Thiopental (39 total), please visit the HSDB record page.

They cause slurred speech, disorientation and "drunken" behavior. They are physically and psychologically addictive. May cause a potentially dangerous rash that may develop into Stevens Johnson syndrome, an extremely rare but potentially fatal skin disease.

Thiopental is distributed into milk in humans; colostrum-to-plasma ratios 4 and 9 hours after induction anaesthesia with the drug reportedly were 0.67 and 0.68, respectively.

In two groups of eight patients, concentrations of thiopentone in mature breast milk and colostrum following anaesthesia induction with 5.4 and 5.0 mg kg-1 bw (mean), respectively, were measured in the first 36 hr postoperatively. Blood concentrations were measured simultaneously. The maximal concentrations were: in mature breast milk, 3.4 +/- 0.68 mumol.L-1 (mean +/- s.e. mean) (0.090 mg 100 mL-1), and in colostrum, 1.3 +/- 0.5 mumol.L-1 (0.034 mg 100 mL-1). The milk/plasma ratio was less than 1.0 in both groups.

Thiopental binds at a distinct binding site associated with a Cl^- ionopore at the GABA_A receptor, increasing the duration of time for which the Cl^- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged.

Overdosage may occur from too rapid or repeated injections. Too rapid injection may be followed by an alarming fall in blood pressure even to shock levels. Apnea, occasional laryngospasm, coughing and other respiratory difficulties with excessive or too rapid injections may occur. Lethal blood levels may be as low as 1 mg/100 mL for short-acting barbiturates; less if other depressant drugs or alcohol are also present.

/SIGNS AND SYMPTOMS/ Neonates born to women who receive barbiturates throughout the last trimester of pregnancy may show withdrawal symptoms from 1-14 days after birth. Withdrawal symptoms, which resemble congenital opiate withdrawal symptoms, include hyperactivity, restlessness, disturbed sleep, tremor, and hyperreflexia. /Barbiturates General Statement/

/SIGNS AND SYMPTOMS/ Symptoms of barbiturate dependence are similar to those of chronic alcoholism, but can be more severe than those associated with alcohol or opiate abstinence syndrome and may result in fatalities. Withdrawal symptoms (which usually appear after 8-12 hours of abstinence) may vary from mild, consisting only of weakness, anxiety, muscle twitches, insomnia, nausea, vomiting, postural hypotension, and/or weight loss, to more severe hallucinations, delirium, and seizures. Seizures, clinically indistinguishable from tonic-clonic (grand mal) seizures, may occur as early as 16 hours after the last dose of barbiturate or may be delayed for as long as 5 days. Some fatalities resulting from cardiovascular collapse have occurred. /Barbiturates General Statement/

/SIGNS AND SYMPTOMS/ Overdosage of barbiturates produces CNS depression ranging from sleep to profound coma to death; respiratory depression which may progress to Cheyne-Stokes respiration, central hypoventilation, and cyanosis; cold, clammy skin and/or hypothermia or later fever, areflexia, tachycardia, hypotension, loss of peripheral vascular resistance, muscular hyperactivity (twitching to convulsive-like movements) seizures, allergic reactions, and decreased urine formation. Pupils usually are slightly constricted but may be dilated in severe poisoning. Patients with severe overdosage often experience typical shock syndrome; apnea, circulatory collapse with loss of peripheral vascular tone, cardiac arrest, respiratory arrest, and death may occur. Complications such as pneumonia, pulmonary edema, or renal failure may also prove fatal. Other complications which may occur are congestive heart failure, cardiac arrhythmias, and urinary tract infections. Some patients have bullous cutaneous lesions which heal slowly. Sweat gland necrosis may also occur. /Barbiturates General Statement/

/SIGNS AND SYMPTOMS/ The toxic dose of barbiturates varies considerably but, in general, a severe reaction is likely to occur when the amount ingested is more than 10 times the usual oral hypnotic dose. Potentially lethal blood concentrations are those in excess of 80 ug/mL for phenobarbital, 50 ug/mL for amobarbital or butabarbital, and approximately 30 ug/mL for secobarbital or pentobarbital; however, some patients have survived much higher blood concentrations. /Barbiturates General Statement/

For more Human Toxicity Excerpts (Complete) data for Thiopental (17 total), please visit the HSDB record page.

Drug-Induced Liver Injury Severity and Toxicity (DILIst)

Thiopental

DILI Negative

Intravenous

DOI:10.1016/j.drudis.2019.09.022

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ The effects of thiopental on chick embryos were analyzed in the present study. Thiopental was dissolved in saline and injected into embryonating chicken eggs at doses ranging from 0.2 to 4.0 mg per egg. The injections were made into the air sacs of eggs after two to four days of incubation. Control eggs were injected with an equivalent volume of saline (0.1 mL per egg). In all 1080 chicken eggs were used for this study. All embryos were examined on day 7. The LD50 for eggs injected on days 2, 3 and 4 was 2.1, 1.9, and 4.1 mg per egg, respectively. The principal malformations observed were exencephaly, anencephaly, twisted limbs, twisted neck, microphthalmia, everted viscera, and hemorrhage above the left eye and in both cerebral hemispheres. The results of the present study indicate that thiopental has a tendency to cause malformations in the chick embryos tested.

/OTHER TOXICITY INFORMATION/ Long-tem animal studdies to determine the carcinogenic and mutagenic potential of thiopental have not been performed ... However, some clinicians state that the drug does not appear to have mutagenic potential in humans.

Barbiturates may elevate blood ammonia. Animal studies indicate that thiopental impairs the ability of the liver to metabolize ammonia. For this reason, it has been suggested that barbiturate administration be avoided in patients with ammonia intoxication. /Barbiturates/

The Generic Animal Drug and Patent Restoration act requires that each sponsor of an approved animal drug must submit to the FDA certain information regarding patents held for the animal drug or its method of use. The Act requires that this information, as well as a list of all animal drug products approved for safety and effectiveness, be made available to the public. Thiopental sodium is included on this list. /Sodium thiopental/

Sodium thiopental for injection. ... It is used as an anesthetic for intravenous administration to dogs and cats during short to moderately long surgical and other procedures. It is also used to induce anesthesia in dogs and cats which then have surgical anesthesia maintained by use of a volatile anesthetic. /Sodium thiopental/

MEDICATION

MEDICATION (VET)

Use (kg) in Switzerland (2009): >1

For use as the sole anesthetic agent for brief (15 minute) procedures, for induction of anesthesia prior to administration of other anesthetic agents, to supplement regional anesthesia, to provide hypnosis during balanced anesthesia with other agents for analgesia or muscle relaxation, for the control of convulsive states during or following inhalation anesthesia or local anesthesia, in neurosurgical patients with increased intracranial pressure, and for narcoanalysis and narcosynthesis in psychiatric disorders. Used commonly in the induction phase of general anesthesia. (Sodium-)thiopental is a depressant and is sometimes used during interrogations - not to cause pain (in fact, it may have just the opposite effect), but to weaken the resolve of the subject and make him or her more compliant to pressure. [Wikipedia]