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Barbiturates
were first introduced for medical use in the early
1900s. More than 2,500 barbiturates have been synthesized,
and at the height of their popularity, about 50
were marketed for human use. Today, about a dozen
are in medical use. Barbiturates produce a wide
spectrum of central nervous system depression, from
mild sedation to coma, and have been used as sedatives,
hypnotics, anesthetics, and anticonvulsants. The
primary differences among many of these products
are how fast they produce an effect and how long
those effects last. Barbiturates are classified
as ultrashort, short, intermediate, and long-acting.
The ultrashort-acting barbiturates produce anesthesia
within about one minute after intravenous administration.
Those in current medical use are the Schedule IV
drug methohexital (Brevital®), and the Schedule
III drugs thiamyl (Surital®) and thiopental
(Pentothal®). Barbiturate abusers prefer the
Schedule II short-acting and intermediate-acting
barbiturates that include amobarbital (Amyta®),
pentobarbital (Nembutal®), secobarbital (Seconal®),
and Tuinal (an amobarbital/secobarbital combination
product). Other short and intermediate-acting barbiturates
are in Schedule III and include butalbital (Fiorina®),
butabarbital (Butisol®), talbutal (Lotusate®),
and aprobarbital (Alurate®). After oral administration,
the onset of action is from 15 to 40 minutes, and
the effects last up to six hours. These drugs are
primarily used for insomnia and preoperative sedation.
Veterinarians use pentobarbital for anesthesia and
euthanasia.
Long-acting barbiturates include phenobarbital (Luminal®)
and mephobarbital (Mebaral®), both of which
are in Schedule IV. Effects of these drugs are realized
in about one hour and last for about 12 hours, and
are used primarily for daytime sedation and the
treatment of seizure disorders.
Source: DEA |
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