Meaning of Sedatives

Also called sedatives, they are drugs that decrease pain and fight insomnia, states of anxiety and psychomotor agitation. Many of them have a hypnotic effect, inducing sleep. Also classified as hypnosedative, they are appropriate for different types of agitation and anxiety, even in cases of psychotic seizure, although they do not have specific antipsychotic effects.

Hypnosedatives, used to produce drowsiness, together with alcohol, opinions and belladonna, were the only medications known to have sedative properties, that is, to calm anxious and agitated patients. Its role as a sedative is still important, despite the therapeutic arsenal having a large number of tranquilizers, which are distinguished by producing less drowsiness. however, some of these drugs, predominantly anxiolytic in action (sedatives), are also used as hypnotics.

Most hypnosedatives are general depressants, attacking the central nervous system and a series of vital cellular activities. To do this, it is essential to have a thorough knowledge of the action and risks posed by these drugs, so that their use will benefit and not harm the patient.

These types of drugs can act on the waking state (nooleptics), which include hypnotics (sleeping pills), barbiturates or not; or on mood (thymoleptics), a subgroup that includes neuroleptics (phenothiazine, reserpines and butyrophenones) and tranquilizers (meprobamate, diazepines).

Hypnotics: fight insomnia
barbiturates (Ex: Gardenal)
non-barbiturates (Ex: Mogadon, Dalmadorm, Dormonid, Sonebon)
Anxiolytics: tranquilizers that decrease anxiety
Narcotics or hypnoanalgesics: they have three fundamental pharmacological properties, such as relieving pain, producing hypnosis and induce dependence on
natural opiates (eg morphine and codeine)
semi-synthetic opiates (eg heroin )
synthetic opiates (eg methadone)
solvents (shoemaker’s glue, benzine, acetone)


They are medicines used to control people’s anxiety and nervousness, causing physical and psychological dependence.

Psychic effects: Tranquility, relaxation, sleep induction, reduced alertness.
Physical Effects: Muscle hypotonia (the person becomes “soft”), difficulty walking, decreased blood pressure and psychomotor reflexes.


The most important group of sedatives and hypnotics derives from barbituric acid, the medicines of which are, therefore, put together under the generic name of Barbit├║ricos. Barbituric acid (malonylurea) results from the combination of diethyl ether malonic acid with urea and was obtained for the first time by Adolph von Bayer, in 1864.

However, the central nervous system depressant property is not related to the barbituric acid itself, but to the replacement of two carbon hydrogen atoms in position 5, to put alcohol or aryl groups.

The first hypnotic barbiturate, the barbital was superseded by numerous shorter-acting barbiturates. Thus, in 1912, phenobarbital (commercially, Luminal) appeared, which, besides being a good hypnotic, has properties that make it useful as an anticonvulsant and sedative. Subsequently, more than 2500 barbiturates were synthesized, of which about fifty were even commercialized.

Barbiturates are general depressants, which act on the activities of nerves, smooth skeletal muscles and cardiac muscles, decreasing the consumption of oxygen in various mammalian tissues. Due to the great susceptibility of the central nervous system to barbiturates, it can be depressed by small dose of the drug, without other systems being affected. Although the action of barbiturates in the conduction and transmission of impulses in peripheral nerves is known, there is still controversy in attributing to this mechanism the hypnotic action of the medication.

The degree of depression produced by barbiturates in the central nervous system varies from mild depression to a coma. Such variation depends not only on the dose and type of barbiturates used, but also on the susceptibility of the central nervous system at the time of administration. This susceptibility may be reduced due to the tolerance resulting from repeated administration of the drug, with the consequent resistance of the individual.

In many ways, barbiturate-induced sleep is similar to normal (physiological) sleep. The main difference is in the reduction of the fundamental phase of physiological sleep, known for paradoxical sleep, whose deprivation leads to various harmful effects. In this phase, there is an increase in electroencephalographic activity, accompanied by rapid eye movements, extremity movements and decreased muscle tension. With the continuous use of barbiturates, the action of the medication on the paradoxical phase decreases and, with the withdrawal of it, there is a marked increase in this phase, with irregularities in the sleep cycle, with nightmares and the sensation of having slept badly.

Barbiturates have a number of side effects, ranging from subtle changes in mood and judgment and motor coordination to depression of the respiratory center. They can also cause addiction, in the same way as several other non-barbiturate hypnosedatives.
Psychic effects: Drowsiness, feeling calm and relaxed, feeling drunk.
Physical effects: Affects breathing, heart and blood pressure, causing difficulty in moving and heavy sleep.