Barbiturates phenobarbital

BARBITURATES. The barbiturate phenobarbital (Luminal) is commonly used to treat convulsive disorders. When administering the barbiturates by the intravenous (IV) route, it is important not to exceed a rate of 60 mg/min and to administer the drug within 30 minutes of preparation. The nurse monitors the patient carefully during administration of a barbiturate. The blood pressure and respirations are taken frequently. Resuscitation equipment and artificial ventilation equipment are kept nearby. 

Barbiturates Phenobarbital, butalbital, pentobarbital, thiopental Spell et al. 1998... 

From the chemical point of view, formally, antiepileptic drugs could be classified as derivatives of hydantoins (phenytoin, mephenytoin, ethotoin), barbiturates (phenobarbital, mephobarbital, and primidone), succinimides (ethosuximide, methosuximide, phensux-imide), benzodiazepines (diazepam, chlorodiazepoxide, clonazepam, lorazepam), oxazo-lidines (trimethadione, paramethadione), and also valproic acid, carbamazepine, and acetazolamide. 

Barbiturates Phenobarbital- (PB) Status epilepticus Epilepsy, all forms Tonic-clonic 40 to 60 Liver 25% eliminated unchanged in urine... 

A. is frequently decreased in individuals treated with drugs, such as the barbiturate phenobarbital. 

Phenobarbital is utilized as a daytime sedative and anticonvulsant. It also induces several cytochrome P450 isozymes. Compared to other barbiturates, phenobarbital has a low oil/water partition coefficient, which results in slow distribution into the brain. It is available for oral, intravenous, or intramuscular administration. Doses for epileptic patients range from 60 to 200 mg per day. After a single oral dose of 30 mg, peak serum concentrations averaged 0.7 mg/L (n = 3). Repeated doses over a period of 7 days resulted in an average peak concentration of 8.1 mg/L.6 Chronic administration of 200 mg per day as anticonvulsant medication resulted in an average blood concentration of 29 mg/L (range = 16 to 48 mg/L).8... 

The long-acting barbiturates phenobarbital (Luminal) and mephobarbital (Mebaral) are used medically to help a patient sleep. Another use is day-long sedation, a procedure that treats tension and anxiety. Furthermore, long-acting barbiturates are used with other drugs in the treatment of convulsive conditions like epilepsy. 

Most of the sedative-hypnotics are capable of inhibiting the development and spread of epileptiform activity in the central nervous system. Some selectivity exists in that some members of the group can exert anticonvulsant effects without marked central nervous system depression (although psychomotor function may be impaired). Several benzodiazepines—including clonazepam, nitrazepam, lorazepam, and diazepam—are sufficiently selective to be clinically useful in the management of seizure states (see Chapter 24 Antiseizure Drugs). Of the barbiturates, phenobarbital and metharbital (converted to phenobarbital in the body) are effective in the treatment of generalized tonic-clonic seizures. 

Use of barbiturates combined with many other medications has been reported to alter the effects of barbiturates or the other drugs. Most of these drug interactions have been specifically reported with the barbiturate phenobarbital. There are... 

OXCARBAZEPINE 1. BARBITURATES-phenobarbital 2. PHENYTOIN t levels of these antiepileptics Uncertain Watch for early features of toxicity... 

VIGABATRIN 1. BARBITURATES-phenobarbital, primidone 2. PHENYTOIN i levels of these antiepileptics Possibly induction of metabolism Watch for poor response to these antiepileptics... 

E Respiratory depression is seen with benzodiazepines (lorazepam, diazepam) and with barbiturates (phenobarbital, pentobarbital). Both classes are associated with sedation, somnolence, and respiratory depression. However, both phenytoin and fos-phenytoin do not affect respiratory rate. 

Carbamazepine (Tegretol) Phenytoin (Dilantin) Barbiturates (phenobarbital) response... 

Barbiturates (phenobarbital can be assayed without sample pretreatment)... 

Long-acting Long-acting barbiturates (phenobarbital and mephobarbital) control epileptic seizures... 

Barbiturates (Phenobarbital, mephobarbital, primidone) Treat grand mal and acute episodes or status epilepticus, meningitis, toxic rations, and eclampsia... 

Barbiturates phenobarbital, secobarbital Benzodiazepines alprazolam, diazepam, lorazepam, triazolam Others buspirone, zolpidem BZ receptor antagonist flumazenil Carbamazepine, ethosuximide, valproic acid, phenytoin, clonazepam, diazepam, lorazepam, gabapentin... 

In addition, there are some hepatic metabolic uses. Because hepatic glucuronyl transferase and the bilirubin-binding Y protein are increased by the barbiturates, phenobarbital has been used successfully to treat hyperbilirubinemia and kernicterus in the neonate. The nondepressant barbiturate phetharbital (A-phenylbarbital) works equally well. Phenobarbital may improve the hepatic transport of bihrubin in patients with hemolytic jaundice. 

Barbiturates Phenobarbital, pentobarbital, thiopental Secobarbital, methohexital... 

Conjugation of the heterocyclic nitrogen with glucosides. This unusual conjugation pathway can be as important as oxidative metabolism in the biotransformation of 5,5-disubstituted barbiturates (phenobarbital, amobarbital, pentobarbital). In humans, a pronounced product enantioselectivity is observed for excretion of these metabolites (47). 

A series of other barbiturates (phenobarbital, barbital, thiopental, pentobarbital at 1 mmol l i concentration inhibit the orotate uptake system without affecting the incorporation of uracil into cellular pyrimidines [287]. While barbituric acid and hexobarbital are less active, phenylethylhydan-toin, chlorpromazine and phenethyl alcohol are extremely active. Phenobarbital also depresses the utilization of orotic acid for the synthesis of cytidine nucleotides in the liver [288]. a-Hexachlorocyclohexane, an inhibitor of the phenobarbital type, was even more effective in depressing de novo cytidine nucleotide synthesis from orotic acid [289]. 

Often a single drug will have many metabolites including some which have effects similar to the parent (cyclosporin, chlorpromazine). Microsomal drug metabolism can be stimulated by medications such as the barbiturate phenobarbital or by cigarette smoke. Metabolism may be slowed by medications such as the monoamine oxidase inhibitors which are used in treatment of psychiatric disease. There are genetic and sex-related differences as well as age-related effects which may affect an individual patient s metabolism. 

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