Sedatives, also known as tranquilizers, are substances that reduce excitement or irritability, leading to a state of calmness.
They help to reduce anxiety, fear, and tension by slowing down brain activity.
Sedatives can be categorized into two main groups: minor tranquilizers (anxiolytics) and major tranquilizers (antipsychotics).
Hypnotics:
Hypnotics, on the other hand, are substances that induce sleep.
They are often used to treat conditions like insomnia. While some sedatives can act as hypnotics at higher doses, hypnotics generally have a more pronounced effect on sleep.
Common Sedatives and Hypnotics:
Some common sedatives include benzodiazepines (like diazepam and alprazolam), barbiturates, and certain antidepressants.
Hypnotics include drugs like zolpidem, eszopiclone, and zaleplon.
Mechanism of Action:
Most sedatives and hypnotics work by enhancing the action of a neurotransmitter known as gamma-aminobutyric acid (GABA) in the brain.
GABA is an inhibitory neurotransmitter, meaning it reduces the activity of neurons in the brain.
By enhancing GABA's action, these drugs effectively slow down brain activity, leading to a state of relaxation or sleep.
Side Effects and Risks:
While sedatives and hypnotics can be highly effective, they also carry risks.
Side effects can include drowsiness, dizziness, confusion, memory issues, and physical dependence or addiction with long-term use.
There is also a risk of overdose, which can lead to severe respiratory depression and even death.
Therefore, these medications should always be used under the supervision of a healthcare professional.
Classification of Sedatives and Hypnotics:
· Sedatives and hypnotics can be classified based on their chemical structure and their mechanism of action.
Here are some of the most common classes:
1.Benzodiazepines:
Mechanism:
Act on the GABA-A receptor complex, enhancing the effect of the neurotransmitter GABA.
Use:
Anxiety relief, sedation, muscle relaxation, anticonvulsant, and amnesic effects.
Examples:
Chlordiazepoxide
Diazepam
Oxazepam
Chlorazepate
Lorazepam
Alprazolam
Zolpidem (Although not a benzodiazepine structurally, it acts on a similar site on the GABA-A receptor complex)
2. Barbiturates:
Mechanism:
Act on the GABA-A receptor complex, but in a different manner than benzodiazepines. They prolong the opening of the chloride ion channel.
Use:
Sedation, induction of sleep, pre-anesthetic, and treatment of seizures.
Examples:
Barbital
Phenobarbital
Mephobarbital
Amobarbital
Butabarbital
Pentobarbital
Secobarbital
3. Miscellaneous:
Amides & Imides:
Glutethimide: An older sedative-hypnotic that has largely been replaced by safer medications.
Alcohol & Their Carbamate Derivatives:
Meprobamate: An early anxiolytic with muscle relaxant properties.
Ethchlorvynol: A sedative and hypnotic medication.
Aldehyde & Their Derivatives:
Triclofos Sodium: A prodrug of trichloroethanol used as a sedative and hypnotic.
Paraldehyde: An older sedative and hypnotic, not commonly used today.
