Generality
Sleeping pills are drugs used to treat insomnia.
Insomnia is a sleep disorder characterized by difficulty falling asleep, which can be more or less pronounced, and a lack of sleep, both quantitatively and qualitatively.
The use of sleeping pills for the treatment of insomnia is necessary when this disorder becomes debilitating for the patient; in fact, the chronic lack of rest is able to exert negative effects also on the diurnal life of the individual.
Below, the main classes of sleeping pills used in therapy will be briefly illustrated. However, before continuing, a clarification is necessary: currently, the term "sleeping pills" is not widely used, as it is preferred to define these drugs in a more specific way as "sedative-hypnotic".
Barbiturates
Barbiturates were among the first drugs to be used to combat sleep disorders.
In addition to being used as sleeping pills, barbiturates are also endowed with anxiolytic, anticonvulsant and anesthetic activities.
Actually, nowadays, barbiturates are considered rather obsolete active ingredients for the treatment of insomnia; for this reason, their use as sleeping pills has been greatly reduced, in favor of other safer drugs. In fact, these drugs have a rather narrow therapeutic index and are also endowed with a certain toxicity.
Their use is mostly limited to the anesthetic field (such as, for example, in the case of thiopental, which is considered a general intravenous anesthetic) and to the treatment of convulsive disorders (as in the case of phenobarbital, which is used as an anticonvulsant in therapy epilepsy).
Action mechanism
The barbiturates are able to exert their action of sleeping pills through the interaction with the GABA-A receptor of γ-aminobutyric acid (or GABA).
GABA-A is a channel receptor which, following interaction with its GABA ligand, is activated and allows the entry of chlorine ions into nerve cells; in this way it has a depressive effect on the central nervous system (or CNS). Not surprisingly, GABA is the main inhibitory neurotransmitter present in our body.
More in detail, barbiturates bind to a specific site present on GABA-A receptors, called the picrotoxin site. Thanks to this bond, the barbiturates activate the receptor, allowing the opening of the canal and thus generating an increase in GABAergic transmission, with consequent induction of sleep.
Side effects
In addition to having a narrow therapeutic index, barbiturates can cause different types of side effects, some of which are also serious.
For this reason, generally, it is preferred to avoid their use as sleeping pills.
Among the main undesirable effects that can occur following the use of barbiturates, we recall:
- Confusion, particularly in older patients;
- Respiratory depression;
- Excessive sedation;
- Decreased contractility of the heart muscle;
- Ataxia;
- nystagmus;
- Disorders of consciousness that can even lead to coma;
- Tolerance and dependence (both physical and mental).
Furthermore, the paradoxical effect that barbiturates are able to exercise should not be underestimated. In fact, if taken at low doses, these active ingredients cause agitation and hyper-excitation.
Benzodiazepines
Benzodiazepines (or BZDs) can be defined as the main sleeping pills used in the treatment of short-term insomnia, but not only.
In fact, similarly to what was said for barbiturates, benzodiazepines also have anxiolytic, anticonvulsant and even muscle relaxant properties.
The main benzodiazepines used as sleeping pills include diazepam (Valium®, Ansiolin®), lorazepam (Tavor®), flurazepam (Felison®) and bromazepam (Lexotan®, Compendium®).
Action mechanism
Benzodiazepines exert their activity as sleeping pills through a mechanism of action very similar to that exercised by barbiturates.
Indeed, benzodiazepines also possess a specific binding site on GABA-A receptors of γ-aminobutyric acid. This site takes the name of "specific binding site for benzodiazepines (or BZR)".
Therefore, benzodiazepines also induce sleep through increased central GABAergic transmission.
Side effects
Unlike barbiturates, benzodiazepines are considered to be relatively safe sleeping pills. In fact, they have a rather high therapeutic index and low toxicity.
In any case, even these active ingredients can cause adverse effects. Among these, we recall:
- Paradoxical symptoms (such as anxiety, agitation, restlessness, delusions, aggression, psychosis);
- Depression;
- Anterograde amnesia;
- Excessive sedation;
- Daytime sleepiness;
- Ataxia;
- Physical and psychic dependence;
- Tolerance.
Medications Z
Z drugs (otherwise known as Z Drugs) are sleeping pills completely different from one another from the chemical point of view. The only point that these molecules have in common is the initial of their name, from which derives the wording "Z Drugs".
To this particular category of sleeping pills belong zolpidem (Stilnox®), zaleplon (Sonata®, Zerene®) and zopiclone (Imovane®).
Action mechanism
The mechanism of action by which the Z drugs exert their action as sleeping pills is the same as that used by benzodiazepines. In fact, these molecules - although they do not possess a benzodiazepine-type chemical structure - are able to bind to the specific binding site for the benzodiazepines present on the GABA-A receptor, thus increasing the transmission of γ-aminobutyric acid and favoring the appearance of sleep.
Thanks to this ability, these active ingredients are often referred to as benzodiazepine-like drugs.
Side effects
Compared to benzodiazepines, Z drugs seem to have less power to induce physical and mental dependence. Despite this, this undesirable effect can still manifest itself, generally, in a dose-dependent manner.
Other side effects that may arise from the use of these drugs are:
- Paradoxical symptoms (such as agitation, restlessness, aggravation of insomnia, hallucinations, nightmares, aggressiveness);
- Rebound insomnia;
- Anterograde amnesia;
- Sleepwalking;
- Headache;
- Dizziness.
Natural Sleeping Pills
There are several plants whose extracts are used as natural sleeping pills. Among these, we remember the valerian, the lemon balm, the passionflower, the chamomile and the hops .
Inside these plants are contained active ingredients able to exert a sedative action and, in some cases, even anxiolytic. Therefore, their use can be useful to counter insomnia and sleep disorders, also associated with anxiety.
However, if you suffer from insomnia, it is always good to ask your doctor's advice and avoid self-therapy, both with natural sleeping pills and with sleeping pills of synthetic origin, such as benzodiazepines, barbiturates or Z drugs.
