Barbiturates are drugs that can be fast or slow acting. They cause drowsiness, sedation, and may have an anticonvulsant action. However, they can be highly addictive and cause serious side effects such as respiratory distress. In France, only phenobarbital, used to treat epilepsy, is authorized.
1. What is the list of existing barbiturate drugs?
Barbiturates are drugs that act on the central nervous system. They have a depressive action which can be very rapid or take longer to set in place. Barbiturates represent a family of molecules derived from barbituric acid. There are many barbituric acid medications, all with different therapeutic effects. These medications can be in tablet form, or in injectable form.
Allobarbital (Dialog) and barbital (Malonal) are used to treat insomnia. Amobarbital (Amytal), butobarbital (Soneryl), pentobarbital (Nembutal), and secobarbital (Seconal) are medications used for their sedative effects. Methylphenobarbital (Prominal) and phenobarbital (Gardenal) are primarily used to treat epilepsy. Other barbiturate medications exist such as Butalbital (Lanorinal), cyclobarbital (Cyclodorm), secbutabarbital (Butabarb) or even Vinylbital (Optanox). These 12 barbiturate drugs are under international control because of their potential danger, as specified inEuropean Monitoring Center for Drugs and Drug Addiction on its page Barbiturate: drug fact sheet.
2. What are the indications for barbiturates?
Barbiturates are drugs that have been used extensively in the past, but are now avoided. Their deep sedative action has been used to treat certain psychiatric conditions, but also to combat insomnia. Barbiturates have been used in general anesthesia, to treat newborn withdrawal syndrome, or to treat certain epileptic seizures. Since they can cause significant and serious side effects, they have gradually been abandoned in favor of other medications such as benzodiazepines. Barbiturates can in fact cause a violent withdrawal syndrome, and can cause physical and psychological dependence. They interact with many medications, and their dosage is not easy. The French Chemical Society also points out that these drugs are responsible for nearly a third of drug-related deaths (linked to drug overdose).
Currently, barbiturates are indicated only for the treatment of epilepsy. Indeed, their action reinforces the actions of GABA in the brain, which has the effect, in particular, of reducing the electrical activity of neurons. Barbiturates, and phenobarbital more specifically, can be used to treat partial epilepsy and generalized epilepsy. Moreover, only phenobarbital can be prescribed in France, as indicated by the French Society of Emergency Medicine on its page dedicated to barbiturates.
3. What are the contraindications of barbiturates?
Barbiturate medications can interact with many medications, making them potentially very dangerous. Currently, barbiturates are only used in the treatment of epilepsy, in the form of phenobarbital. Barbiturates should not be used in cases of allergy or hypersensitivity to barbituric acid and its derivatives. Phenobarbital should not be used in cases of porphyria or severe respiratory failure. Certain medications should not be combined with phenobarbital because their action may be impaired, which may lead to serious side effects. Phenobarbital should therefore not be combined with the antifungal voriconazole, cholic acid, cobicistat or rilpivirine (used as part of HIV treatment). Phenobarbital should not be combined with medicines used to treat hepatitis, for example dasabuvir, ledipasvir or sofosbuvir, because it increases their hepatic metabolism.
Certain herbal medicines such as medicines containing St. John’s Wort should also not be used. The action of many medications (oral anticoagulants, calcium antagonists, corticosteroids) can be reduced, so it is important to avoid taking phenobarbital at the same time as these molecules. The dosage of barbiturates must always be extremely precise, as the risk of overdose is significant. The association with other substances that can act on the central nervous system (other antidepressants, alcohol, drugs) should be prohibited.
Sources
- Barbiturates: drug fact sheet, European Monitoring Center for Drugs and Drug Addiction
- Barbiturates, French Chemical Society
- Barbiturates (phenobarbital), French Society of Emergency Medicine
- Gardenal 100 mg tablet, Public Drug Database, July 1, 2023
- Phenobarbital, National College of Medical Pharmacology, May 31, 2017