Thiopental status epilepticus

Refractory status epilepticus that has failed to respond to one of these treatments, and has continued for more than 20-30 min, requires urgent action. The accepted strategy is to paralyze and ventilate the patient and administer an antiepileptic drug in sufficient dosage to suppress EEG evidence of seizure activity. The barbiturate anaesthetic thiopental (thiopentone), the benzodiazepine midazolam, and the anaesthetic propofol have all been used. What little comparative evidence there is remains inconclusive. Such treatment can only be carried out with facilities for artificial ventilation and intensive care, and effects can only be monitored by EEG recording. 

When utilized as sedative hypnotics, barbiturates are administered orally. They are rapidly and completely absorbed by this route with nearly 100% bioavailability and an onset of action ranging from 10 to 60 min.3 Sodium salts are more rapidly absorbed than free acids. Intramuscular injections of sodium salts should be made deep into the muscle to prevent pain and tissue damage. Some barbiturates are also administered rectally barbiturates utilized for the induction and maintenance of anesthesia (thiopental) or for treating status epilepticus (phenobarbital) are administered intravenously. 

Convulsions have been reported in two patients with no history of epilepsy after induction of anesthesia with propofol (44). However, in a crossover comparison in 20 epileptic patients undergoing cortical resection, in which the effects on the electrocorticogram of either propofol or thiopental during isoflurane + nitrous oxide anesthesia were studied, propofol caused no greater proconvulsive effect than thiopental, which is used to treat status epilepticus (45). In spite of occasional reports, a true epileptogenic effect of propofol remains to be proven. 

Because it markedly lowers cerebral metabolism, thiopental has been used as a protectant against cerebral ischemia. At least one human study suggests that thiopental may be efficacious in ameliorating ischemic damage in the perioperative setting. Thiopental also reduces intraocular pressure. Perhaps due to their CNS depressant activity, barbiturates are effective anticonvulsants thiopental in particular is effective in the treatment of status epilepticus. 

ABSORPTION, FATE, AND EXCRETION For sedative-hypnotic use, the barbiturates usually are administered orally (Table 16-3) absorption is rapid and nearly complete. The onset of action varies from 10-60 minutes, depending on the agent and the formulation, and is delayed by the presence of food in the stomach. When necessary, intramuscular injections of solutions of the sodium salts should be placed deeply into large muscles to avoid the pain and possible necrosis that can result at more superficial sites. The intravenous route usually is reserved for the management of status epilepticus (phenobarbital sodium) or for the induction and/or maintenance of general anesthesia (e.g., thiopental or methohexital). 

Status epilepticus i.s defined as continuou.s seizure.s lasting at least 30 minute.s or a state in which fits follow each other without consciousness being fully regained. Urgent treatnient with intravenous agents (bottom left) is neccs.sary to Stop the fits, which, if unchecked, result 111 exhaustion and cerebral damage. Lorazepam or diazepam is used initially followed hy phenyloin if necessary, [f the fits are not controlled, the patient is anaesthetized with propofol or thiopental. 

An 8-month-old boy who had been given oral modifled-release theophylline and additional aminophylline suppositories developed convulsive status epilepticus [96 ]. A combination of diazepam, lidocaine, and thiopental was required to stop the convulsion. A pharmacokinetic study showed that the use of the mod-ified-release formula would have given a plasma concentration of no more than 15 mg/ 1, but that the addition of aminophylline would have increased it to over 20 mg/1. 

Cereda C, Berger MM, Rossetti AO. Bowel ischemia a rare complication of thiopental treatment for status epilepticus. Neurocrit Care 2009 10(3) 355-8. 

Phenobarbital and thiopental (Fig. 4.3) are still used in clinics. Phenobarbital is reserved for a serious type of epilepsy called status epilepticus, while thiopental is used in general anesthesia. 

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