Barbiturates and benzos (benzodiazepines) are two groups of drugs that were primarily designed to treat clinically significant anxiety and seizures as well as to enhance sleep.
Their primary difference is in their chemical structure and mechanism of action.
Benzodiazepines are among the most prescribed drugs in the United States.
Some of the more common benzodiazepines include:
Barbiturates were once one of the most prescribed classes of drugs in the country, but benzodiazepines have largely replaced them.
The major barbiturate drugs include:
Although these classes of drugs are very similar in their mechanism of action and use, the first key difference between them is that they are different classes of chemicals.
The generic or chemical names for benzodiazepines typically end in the letters “am,” whereas the generic names for barbiturates end with “tal.” These are two different classes of chemical substances.
Barbiturates are chemical derivatives of a substance called barbituric acid, whereas benzodiazepines are synthetically produced by fusing chemicals like benzene and diazepine.
Benzodiazepines and barbiturates have a very similar mechanism of action. Both increase the availability of the major inhibitory neurotransmitter in the central nervous system: gamma-Aminobutyric acid, or GABA for short.
This neurotransmitter is responsible for modulating the activity of other neurons in the central nervous system, specifically by slowing down their rates of firing. Thus, both classes of drugs are often referred to as central nervous system depressants. Their actions depress or reduce the activity of neurons in the brain and spinal cord.
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Both classes of drugs will exert similar effects that include a reduction in anxiety, feelings of sedation, seizure control, and feelings of well-being or euphoria. These effects are associated with their ability to suppress the functioning of neurons (nerves) in the central nervous system.
Very often, these drugs produce feelings of being uninhibited, giddiness, and resilience from potential stress or anxiety-provoking situations.
These two drugs differ in the exact way they increase the availability of GABA.
Both classes of drugs work on the GABAA receptor, but benzodiazepines amplify GABA by increasing the frequency of the opening of the chloride channels in these neurons, allowing for greater GABA availability.
Barbiturates increase the time that the chloride channels in the neurons remain open and not the frequency of their opening.
Both effects result in increased levels of GABA and the medicinal effects of the drugs.
In general, barbiturates are deemed to be the more potent of the two classes of drugs. This means that barbiturates will often exert their effects in smaller doses than benzodiazepines.
Because they are so potent, barbiturates were considered to be highly addictive, even more addictive than benzodiazepines. Because of issues with barbiturate abuse, benzodiazepines were developed to take over many of the medicinal functions that barbiturates once performed.
Both drugs are controlled substances, but barbiturates are often considered to have a greater potential for abuse, overdose, and the development of physical dependence.
Both drugs have similar medicinal uses.
They are most effective in treating significant anxiety (anxiety associated with anxiety disorders or other mental health disorders), reducing seizures in those with seizure disorders, and inducing sleep.
In addition, they may help treat withdrawal from alcohol and other drugs. Most often, benzodiazepines are used for this purpose.
When benzodiazepines were developed, they were believed to have less potential for abuse than barbiturates, but benzodiazepines are significant drugs of abuse.
The Substance Abuse and Mental Health Services Administration (SAMHSA) releases yearly data that indicates that Xanax (a benzodiazepine) is one of the most misused drugs in the United States. According to the same data, benzodiazepine misuse and abuse far outweigh abuse of barbiturates.
Given their similar mechanisms of action, both drugs can be noteworthy drugs of abuse. There is likely little difference in their actual abuse potential.
The effects of an overdose of barbiturates and benzodiazepines will often be very similar. They include lethargy, problems with movement, coordination issues, slurred speech, and other symptoms that are very similar to severe intoxication with alcohol.”
An overdose of barbiturates is more likely to result in significant respiratory depression than a benzodiazepine overdose.
Treatment for an overdose on either barbiturates or benzodiazepines might include breathing support, IV fluids, medicines to address specific symptoms, and activated charcoal by mouth if the overdose was taken orally.
There is no direct antidote for a barbiturate overdose; however, the medication Romazicon (flumazenil) may be used to treat benzodiazepine overdose. This drug is classified as a GABA receptor antagonist that removes benzodiazepines from the neurons. As a result, it can help to reverse the symptoms of an overdose.
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(September 2018) Barbiturates. RxList. from https://www.rxlist.com/consumer_barbiturates/drugs-condition.htm
(January 2015) Anxiety disorders and GABA neurotransmission: A disturbance of modulation. Neuropsychiatric Disease and Treatment, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4303399/
(October 2015) GABA receptors: pharmacological potential and pitfalls. Current Pharmaceutical Design. from https://bib.irb.hr/datoteka/784286.Jazvinscak_and_Vlainic_CPD_2015.pdf
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Drug Scheduling. Drug Enforcement Administration. from https://www.dea.gov/drug-scheduling
(March 2019) Romazicon. RXList. from https://www.rxlist.com/romazicon-drug.htm
(October 2018) National Survey on Drug Use and Health: Detailed Tables. Substance Abuse and Mental Health Services Administration. from https://www.samhsa.gov/data/sites/default/files/cbhsq-reports/NSDUHDetailedTabs2017/NSDUHDetailedTabs2017.pdf