Long-acting barbiturates

Long-acting (eg, phenobarbital, mephobarbital [Mebaral]). The averse duration of action of the long-acting barbiturates is 10 to 16 hours. 

The Summary Drug Table Sedatives and Hypnotics Barbiturates gives examples of the short-, intermediate-, and long-acting barbiturate sedatives and hypnotics. 

Long-acting barbiturates used as sedative-hypnotics and also for their anticonvulsant effects include phenobarbital (Luminal) and mephobarbital (Mebaral). 

Several animal studies indicate that chloroform interacts with other chemicals within the organism. The lethal and hepatotoxic effects of chloroform were increased by dicophane (DDT) (McLean 1970) and phenobarbital (a long-acting barbiturate) in rats (Ekstrom et al. 1988 McLean 1970 Scholler 1970). Increased hepatotoxic and nephrotoxic effects were observed after interaction with ketonic solvents and ketonic chemicals in rats (Hewitt and Brown 1984 Hewitt et al. 1990) and in mice (Cianflone et al. 1980 Hewitt et al. 1979). The hepatotoxicity of chloroform was also enhanced by co-exposure to carbon tetrachloride in rats (Harris et al. 1982) and by co-exposure to ethanol in mice (Kutob and Plaa 1962). Furthermore, ethanol pretreatment in rats enhanced chloroform-induced hepatotoxicity (Wang et al. 1994) and increased the in vitro metabolism of chloroform (Sato et al. 1981). 

B arbitur ates are metabolized in the liver via hydroxylation and glucuronide conjugation. Short-acting barbiturates are excreted in the urine as metabolites for about one to four days, while long-acting barbiturates are excreted for two to three weeks. 

Hangover especially with long acting barbiturates. Excitement and restlessness, neuralgic pain, allergic reactions include swelling and erythematous dermatitis. They produce physical dependent and have abuse potential. 

Schedule IV - Drugs have an accepted medical use and are generally the long-acting barbiturates,hypnotics and minor tranquilizers, e.g., meprobamate, phenobarbital. 

Mephobarbital and phenobarbital are long-acting barbiturates that take effect within approximately one to two hours. These effects last approximately 12 hours. 

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. 

Long-acting barbiturates include phenobarbital (Luminal) and mephobarbital (Mebaral). These drugs, which take effect in about one hour and last for about 12 hours, are used primarily for daytime sedation and the treatment of seizure disorders or mild anxiety. Generally, these are not drugs of abuse rather the short- and intermediate-acting barbiturates—such as amobarbital (Amytal), pentobarbital (Nembutal), and secobarbital (Seconal)—are among those most commonly abused. 

Barbital , diethylbarbituric acid, is sold under the trade name Veronal . It is the oldest of the long-acting barbiturates and is derived through diethyl malonate. 

The method does not distinguish between the common 5,5-substituted barbiturates. If the physician proposes to institute a forced alkaline diuresis or haemodialysis, it is essential to confirm the presence of a long-acting barbiturate (e.g, barbitone, phenobarbitone) by thin-layer chromatog-raphy or gas chromatography. 

Some of the barbiturates are slowly metabolized and eliminated by the kidneys. Barbital and phenobarbital arc in this group, and are know n as long-acting barbiturates because their effects last twelve to twenty-four hours. They are used as daytime sedatives more than as nighttime hypnotics, and since they don t produce much euphoria or stimulation, few people take them to... 

See also Barbiturates, Long-Acting Barbiturates, Short-Acting Neurotoxicity. 

The long-acting barbiturates are used for insomnia, anxiety, psychosis, preoperative sedation, and control of seizures. Long-acting barbiturates are utilized as drugs of abuse. This abuse peaked in the 1970s, but has since declined with the increased use of other sedatives. 

The most common route of exposure to the long-acting barbiturates is ingestion of oral dosage forms. Phenobarbital is also available for parenteral administration. 

Approximately 50-90% of the long-acting barbiturates are slowly absorbed from the gastrointestinal tract. Absorption is more rapid when ingested on an empty stomach and in the presence of alcohol. The onset of action varies 30-60 min for mephobarbital... 

Animals may be affected by the long-acting barbiturates much in the same way as humans. Lethargy,... 

Chronic use of high doses of the long-acting barbiturates may produce psychological and physical dependence. Abrupt discontinuation of therapy may result in withdrawal signs and symptoms. Mild withdrawal may include weakness, anxiety, muscle twitching, insomnia, nausea, and vomiting. Severe withdrawal may consist of hallucinations, autonomic instability, delirium, and seizures. Unlike opioid withdrawal. 

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

Appropriate treatment for barbiturate intoxication includes general cardiopulmonary support and measures to prevent further drug absorption and to enhance elimination. Urine alkalinization may enhance the elimination of long-acting barbiturates (e.g., phenobarbital and barbital) but has little effect on intermediate-, short-, or ultrashort-acting barbiturates. 

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