Definition types mechanism of action and uses of sedative hypnotic drugs
The name Sedative hypnotic drugs are deriving the meaning of it, sedative meaning induces calm. While the Hypnotic effect refers to induce sleep. The sedative hypnotic drug is the chemical substance used for reducing tension, anxiety and to induce calm or to induce sleep. Usually, such drugs at low dosage induce the calming effect, while consuming in large dosage it induces a sleeping effect. Sedative hypnotics will depress the central nervous system. These processes can even be archived by using other drugs. But only sedatives and hypnotics have the selective ability to achieve the process without affecting the mood or reducing the sensitivity of pain.
Origin of Sedative Hypnotic Drugs
In the olden day, alcohol and opium were only used as drugs for sedatives and hypnotics. In the 1800s the first alternative for sedative hypnotics has come to market in the form of liquid as bromide salt solution. In 1869, the chloral hydrate is derived from ethyl alcohol, which was used as a synthetic sedative hypnotic drugs. In the 1880s Paraldehyde was introduces into clinical medicine. And it was followed in 1903, by the synthesis of barbital. In 1912, the phenobarbital starts availing in the market and used for the next twenty years. From the mid of 20th century, two new types of sedatives and hypnotics came into use, they are benzodiazepines and Barbiturates. The benzodiazepines are also called minor tranquilizers. In the 20th century, Barbiturates are wide as sleeping pills for the entire first half of the 20th century. These medicines are also used as voluntary inhibition during psychiatric examinations.
Phenobarbital, amobarbital, secobarbital, and pentobarbital are the most commonly prescribed drugs. While intaking these drugs in high dosage are capable of creating deep unconsciousness. So, this was used as general anaesthetics. However, the overdosing of sedative hypnotic drugs side effects the complete central nervous and respiratory systems may lead to coma, respiratory failure, and death. In the 1950s, benzodiazepines were developed and banned the use of Barbiturates. The benzodiazepines are more effective in relieving anxiety for inducing sleep. The benzodiazepines contain, diazepam, alprazolam, chlordiazepoxide, oxazepam and triazolam. Even while intaking the high dosage of benzodiazepines reduces the causes of risk and lesser the depression of the central nervous system. The benzodiazepines are also can create their effect within the brain by creating the actions of the neurotransmitter gamma-aminobutyric acid, which results to inhibit anxiety.
Sedative Hypnotics Classification
Based on its performance, sedative drugs and hypnotic drugs are classified.
Classification of Sedative Drugs
Sedative medications are mainly classified into three types.
Barbiturates
These drugs can be taken on their own or can take along with anaesthesia. This can be used to medicate seizure disorder. Eg: Nembutal and phenobarbital
Benzodiazepines
These drugs are mainly used for treating seizures, muscular spasms, and anxiety. Eg: Librium (chlordiazepoxide), Xanax (alprazolam), Ativan (lorazepam), Valium (diazepam), Halcion (triazolam), Serax (oxazepam), and Klonopin (clonazepam). Rohypnol is 10 times stronger than Valium. So, it is used as date rape.
Z-Drug Sleep Medications
These drugs are mainly used as the receptor in the central nervous system called BZ1, which helps as sleeping assistance. Anyhow, psychologists do not allow the patients to intake this medicine for a long period. For eg. Lunesta (eszopiclone), Ambien (zolpidem), and Sonata (zaleplon).
Classification of Hypnotic Drugs
Hypnotic drugs are also known as soporific drugs. They are used as the medication to treat sleeping illness, insomnia, and also as surgical anaesthesia. Hypnotic drugs are widely classified as Benzodiazepine (BZ) and Non-Benzodiazepine (BZ). They are further widely classified as
Ultra rapidly elimination hypnotics
Rapidly elimination hypnotics
Relatively slow elimination hypnotics
Slow elimination hypnotics
What is the Difference Between Sedative and Hypnotic?
While comparing to the hypnotic, the sedative drugs will act as better analgesia or pain relief.
The Sedative drugs will produce a relaxing and calming effect. So, it can be preferred to intake during the daytime. Hypnotic drugs make patients fall asleep. So, it is can be preferred to take during nighttime.
Sedative Hypnotic Drugs Side Effects
The regular intake of sedative Hypnotic drugs may raise tolerance in the human body and create side effects as listed below.
Dizziness, drowsiness, and confusion.
Feeling depressed and anxiety.
Inappropriate behaviour and Mood swing.
Risk of addiction.
Breathing difficulties.
Trouble on thinking and focusing.
Frequent memory loss.
Liver failure or damage of tissues.
Addicted to drugs.
Feel Nervous and loss of appetite.
FAQs on Sedative Hypnotic Drug in Pharmacology
1. What are sedative hypnotic drugs?
Sedative hypnotic drugs are medications that depress the central nervous system (CNS) to reduce anxiety, promote relaxation, and induce sleep. They act by slowing brain activity and are commonly used to treat insomnia and anxiety disorders.
- Sedatives calm and reduce agitation.
- Hypnotics induce and maintain sleep.
- At higher doses, many sedatives can act as hypnotics.
2. How do sedative hypnotic drugs work in the brain?
Sedative hypnotic drugs work mainly by enhancing the effect of the inhibitory neurotransmitter GABA (gamma-aminobutyric acid) in the brain. This increases neuronal inhibition and reduces CNS activity.
- They bind to GABAA receptors.
- Increase chloride ion influx into neurons.
- Cause hyperpolarization, making neurons less excitable.
3. What is the difference between sedatives and hypnotics?
The main difference between sedatives and hypnotics is that sedatives reduce anxiety and calm the patient, while hypnotics primarily induce sleep. However, the distinction is dose-dependent.
- Sedatives: Lower doses, reduce excitement and anxiety.
- Hypnotics: Higher doses, promote sleep.
- Many drugs (e.g., benzodiazepines) can act as both.
4. What are examples of sedative hypnotic drugs?
Common examples of sedative hypnotic drugs include benzodiazepines, barbiturates, and non-benzodiazepine sleep aids. These drugs differ in potency and safety profiles.
- Benzodiazepines: Diazepam, Lorazepam
- Barbiturates: Phenobarbital
- Z-drugs: Zolpidem, Zaleplon
5. What are benzodiazepines and how do they act as sedative hypnotics?
Benzodiazepines are sedative hypnotic drugs that enhance GABA action by increasing the frequency of chloride channel opening at the GABAA receptor. This leads to CNS depression.
- Produce anxiolytic, sedative, muscle relaxant, and anticonvulsant effects.
- Have a safer therapeutic index than barbiturates.
- Commonly used for anxiety and insomnia.
6. What are the side effects of sedative hypnotic drugs?
The common side effects of sedative hypnotic drugs include drowsiness, impaired coordination, and dependence with prolonged use. These effects result from CNS depression.
- Daytime sleepiness
- Confusion or memory impairment
- Respiratory depression (at high doses)
- Risk of tolerance and physical dependence
7. What is the mechanism of action of barbiturates?
Barbiturates act by prolonging the duration of chloride channel opening at the GABAA receptor, leading to strong CNS depression. At high doses, they can directly activate GABA receptors.
- Decrease neuronal excitability.
- Suppress brainstem respiratory centers at toxic levels.
- Have a narrow therapeutic index.
8. Can sedative hypnotic drugs cause dependence?
Yes, sedative hypnotic drugs can cause physical and psychological dependence with long-term or high-dose use. Dependence develops due to adaptive changes in the CNS.
- Development of tolerance (need for higher doses).
- Withdrawal symptoms such as anxiety and insomnia.
- Risk is higher with barbiturates and some benzodiazepines.
9. What is the role of sedative hypnotic drugs in treating insomnia?
Sedative hypnotic drugs are used in insomnia to reduce sleep latency and improve sleep duration by depressing CNS activity. They help patients fall asleep faster and stay asleep longer.
- Commonly prescribed: Z-drugs and benzodiazepines.
- Best used for short-term management.
- Combined with behavioral sleep therapy for better outcomes.
10. What is the difference between barbiturates and benzodiazepines?
The key difference between barbiturates and benzodiazepines is that barbiturates have a higher risk of respiratory depression and toxicity, while benzodiazepines are generally safer. Both act on GABA receptors but differ in mechanism and safety.
- Barbiturates: Prolong chloride channel opening; narrow therapeutic index.
- Benzodiazepines: Increase frequency of channel opening; wider safety margin.
- Benzodiazepines are more commonly used today.
