Pentobarbital abuse potential

Before the introduction of the benzodiazepines, a number of drugs from different chemical and pharmacological classes were used in the treatment of anxiety and insomnia. However, these drugs are more toxic and produce more serious side effects than do the benzodiazepines. Many also have signihcant abuse potential. Consequently, most of these compounds are no longer widely used. These drugs include the barbiturates (e.g., pentobarbital, amobarbital), carbamates (e.g., meprobamate), piperidinediones (e.g., glutethimide), and alcohols (e.g., ethchlorvynol). 

Several classes of pharmacologic agents are available for insomnia. Barbiturates are the oldest agents that have been used for insomnia and include pentobarbital, secobarbital, and amobarbital. Barbiturates are currently not recommended because of their high abuse potential (due to rapid development of tolerance) and lethal potential in overdose situations. Barbiturates potentiate the GABAergic-induced increase in chloride ion conductance at low doses, and at high doses they depress calcium-dependent action potentials. Caution should be exercised in patients with marked renal or liver dysfunction, severe respiratory disease, suicidal tendencies, or history of alcohol/drug abuse. 

The barbiturates have a low therapeutic index and a relatively high abuse potential. Because of their rapid onset and short duration of action, the short- to intermediate-acting barbiturates are used as sedative-hypnotics (amobarbitai, butabarbital, butalbital, pentobarbital, and secobarbital) and are those most commonly abused. The longer acting barbiturates (mephobarbital and phenobarbital), used primarily for their anticonvulsant properties, are rarely abused. 

Schedule II drags have a high potential for abuse. They are accepted for medical use with restrictions. These drugs may lead to severe psychological or physical dependence. Barbiturates in this category are amo-barbital (Amytal), pentobarbital (Nembutal), and secobarbital (Seconal, Tuinal). 

Schedule 11 drugs have an accepted medical use in the United States and a high rate of abuse, with either severe psychological or physical dependence potential. These drugs include morphine, codeine, cocaine, amphetamine, and most barbiturate preparations containing amobarbital, secobarbital, and pentobarbital. 

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