Anxiolytics - as the name suggests - are drugs used to treat anxiety disorders.
Normal and pathological anxiety
Contrary to what one might think, anxiety is not always pathological; in fact, there are situations in which anxiety is a useful phenomenon for the individual. Therefore, two well defined conditions are distinguished:
- Condition of normal anxiety ;
- Condition of pathological anxiety .
In the condition of normal anxiety we find ourselves in a state of tension - both physical and psychological - characterized by the activation of autonomous reflexes and the waking state, which can be useful to the individual in certain situations. For example, the anxiety that a student may experience before an exam is considered normal anxiety.
Anxiety becomes pathological when it is completely inappropriate with respect to the situation in which one finds oneself or when it is excessive compared to what, normally, the situation would require.
Pathological anxiety, therefore, is able to compromise the normal social and occupational activities of the individual. Therefore, correct diagnosis and appropriate and timely pharmacological and / or psychotherapeutic treatment are very important.
Furthermore, anxiety is often associated with depressive disorders, but it is not clear whether one of the two diseases occurs first or if one is an integral part of the other.
Anxiety disorders include:
- Generalized anxiety disorders;
- Panic attacks, with or without agoraphobia;
- Phobias (such as, for example, social phobia);
- Obsessive-compulsive disorder:
- Post-traumatic stress disorder.
Many studies have been conducted to understand what factors were involved in the onset of pathological anxiety. From these studies it emerged that numerous neurotransmitters, neuromodulators and neuropeptides are involved in the etiology of this disease.
Particular attention has been paid to three neurotransmitters: γ-aminobutyric acid (or GABA ), noradrenaline (or NA ) and serotonin (or 5-HT ).
The main classes of drugs used in anxiolytic therapy are described below.
Barbiturates
Barbiturates - once used to treat anxiety - are obsolete and no longer used to treat this condition, due to their narrow therapeutic index and toxicity. Therefore, they will not be taken into consideration in the following list.
Benzodiazepines
Benzodiazepines are drugs widely used in the treatment of anxiety.
Their mechanism of action is to increase GABAergic transmission, hence the transmission of γ-aminobutyric acid.
GABA is the main inhibitory neurotransmitter of the brain and performs its biological functions by interacting with its receptors, GABA-A, GABA-B and GABA-C.
A binding site for benzodiazepines (BZR) is present on the GABA-A receptor. Benzodiazepines bind to this specific site thus promoting receptor activation and GABA-induced cascade of inhibitory signals.
Among the various benzodiazepines used in the treatment of anxiety disorders, we mention alprazolam, lorazepam, bromazepam, diazepam and clonazepam .
Benzodiazepines have a high therapeutic index, which is why they are considered relatively safe drugs. Among the main side effects that can arise at the therapeutic doses normally used, we recall:
- Excessive sedation;
- Daytime sleepiness;
- Confusion, especially in elderly patients;
- Depression;
- Disorders of coordination;
- Ataxia;
- Memory disorders (anterograde amnesia).
In any case, it should be remembered that the treatment based on benzodiazepines must be as short as possible, since these drugs create tolerance, physical and mental dependence, and addiction.
In addition, benzodiazepines should be used with extreme caution in patients with a history of alcohol and / or drug abuse.
5-HT 1A receptor agonists
The drugs belonging to this class act on the serotonergic system. In particular, they act on brain receptors 5-HT 1A of serotonin.
Azapirons such as buspirone, ipsapirone and gepirone are part of this class of drugs. Buspirone is the only one of these three drugs to have been approved by the Food and Drug Administration (FDA) for marketing in the United States.
The anxiolytic effect of the buspirone is established only after several days - or even weeks - from the beginning of the treatment.
Buspirone is effective in treating low to medium severity generalized anxiety disorders, but it is not as effective in treating panic attacks.
The side effects induced by buspirone are less than those induced by benzodiazepines and include dizziness, headache and nausea, but not sedation and coordination disorders.
Furthermore, buspirone does not cause tolerance and even less dependence.
Selective serotonin reuptake inhibitors (SSRIs)
SSRIs are usually employed in the treatment of depressive disorders. However, it has been shown that some serotonin reuptake inhibitors are also effective in the first-line treatment of some forms of anxiety.
In particular, SSRIs are effective in the treatment of obsessive-compulsive disorders, in the treatment of panic attacks and in the treatment of social phobia.
Among the SSRIs that have anxiolytic properties, we recall:
- Citalopram ;
- Escitalopram ;
- Fluoxetine ;
- Fluvoxamine ;
- Paroxetine ;
- Sertraline .
Β-adrenergic receptor antagonists
Noradrenaline β-adrenergic receptor antagonists - known more simply as β-blockers - are not used to treat anxiety itself, but can be used to reduce physical symptoms caused by it (such as tremors, palpitations, tachycardia, etc.). ).
Among the β-blockers used to alleviate the symptoms of anxiety, we mention propranolol .
Other anxiolytic drugs
There are drugs that do not belong to the classes mentioned above, but which nevertheless exert an anxiolytic action.
hydroxyzine
Hydroxyzine is an antagonist of H1 histamine receptors. It is a first-generation antihistamine drug with anxiolytic activity.
In addition to being used in allergic dermatitis, hydroxyzine is also used to alleviate symptoms caused by anxiety.
It is marketed under the name of Atarax®
Pregabalin
Pregabalin is an active ingredient with anticonvulsant activity, used mainly in the treatment of epilepsy; it is also used in the treatment of neuropathic pain and in the treatment of generalized anxiety disorder.
It is marketed under the name Lyrica®, but the equivalent medicine is also available.
meprobamate
Meprobamate (trade name Quanil®) is a drug belonging to the urethane class. It was once used in the treatment of short-term anxiety and as an adjunct in morbid conditions accompanied by anxiety.
The use of meprobamate, however, has been supplanted by the use of benzodiazepines, as they are more effective and safer than the latter.
