Although all known members of the class possess relevant enzyme induction capabilities, the degree of induction overall as well as the impact on each specific enzyme span a broad range, with phenobarbital and secobarbital being the most potent enzyme inducers and butalbital and talbutal being among the weakest enzyme inducers in the class. People who are known to have killed themselves by barbiturate overdose include Stefan Zweig, Charles Boyer, Ruan Lingyu, Dalida, Jeannine Deckers, Felix Hausdorff, Abbie Hoffman, Phyllis Hyman, C. P. Ramanujam, George Sanders, Jean Seberg, Lupe Vélez and the members of  Heavens Gate cult. Others who have died as a result of barbiturate overdose include Pier Angeli, Brian Epstein, Judy Garland, Jimi Hendrix, Marilyn Monroe, Inger Stevens, Dinah Washington, Ellen Wilkinson, and Alan Wilson; in some cases these have been speculated to be suicides as well. Those who died of a combination of barbiturates and other drugs include Rainer Werner Fassbinder, Dorothy Kilgallen, Malcolm Lowry, Edie Sedgwick and Kenneth Williams. Dorothy Dandridge died of either an overdose or an unrelated embolism. Ingeborg Bachmann may have died of the consequences of barbiturate withdrawal (she was hospitalized with burns, the doctors treating her not being aware of her barbiturate addiction). Contraindications
The use of Barbiturates is contraindicated in the following conditions:

variegate porphyria (because of induction of enzymes needed for porphyria synthesis by barbiturates)
Status asthmaticus (because of respiratory depression caused by the barbiturates)

Mechanism of action
Barbiturates act as positive allosteric modulators and, at higher doses, as agonists of GABAA receptors.
Since this first article, different kind of receptors were designed, as well as different barbiturates and cyanurates, not for their efficiencies as drugs but for applications in supramolecular chemistry, in the conception of materials and molecular devices. The preferred IUPAC name of the base compound, barbituric acid, is  1,3-diazinane-2,4,6-trione. Different barbiturates has different substituents in the basic structure, mainly in position 5 on the ring.Sodium barbital and barbital have also been used as pH buffers for biological research, e.g., in immuno-electrophoresis or in fixative solutions. Classification
Barbiturates are classified based on the duration of action. Examples of each class include:
Ultra short acting (30 minutes): thiopentone, methohexitone
Short acting (2 hours): hexobarbitone, cyclobarbitone, pentobarbitone, secobarbitone
Intermediate acting(3–6 hours): amobarbitone, butabarbitone
Long acting (6 hours): phenobarbitone

Indications
Indications for the use of barbiturates include:
Seizure
Neonatal withdrawal syndrome
Insomnia
Anxiety
Inducing anesthesia

Side effects
There are special risks to consider for older adults, and women who are pregnant. When a person ages, the body becomes less able to rid itself of barbiturates. As a result, people over the age of sixty-five are at higher risk of experiencing the harmful effects of barbiturates, including drug dependence and accidental overdose. When barbiturates are taken during pregnancy, the drug passes through the placenta to the fetus. After the baby is born, it may experience withdrawal symptoms and have trouble breathing. In addition, nursing mothers who take barbiturates may transmit the drug to their babies through breast milk. A rare adverse reaction to barbiturates is Stevens–Johnson syndrome, which primarily affects the mucous membranes.