Haloperidol (antipsychotic): uses, effects and risks
Diazepam, lorazepam, olanzapine, methylphenidate ... Some of these names can be very familiar to read and listen in today's society.
All of them are psychotropic drugs, substances that through certain mechanisms of action fight a series of specific symptoms such as anxiety, depression or hallucinations. They are used in many cases as a treatment of choice or as a first step to control the symptoms of a disorder to be treated through therapy, as a way to keep the symptoms under control or as a reinforcer of the effects of psychological therapy.
In the present article we are going to talk about one of the psychotropic drugs used mainly in the treatment of psychotic symptoms, haloperidol.
What is haloperidol?
Haloperidol is a typical neuroleptic or antipsychotic encompassed within the group of butyrophenones , depressant agents of the central nervous system with sedative effect and which act as very potent antagonists of cerebral dopamine receptors. That means that they prevent certain neurons from absorbing the neurotransmitter known as dopamine.
Haloperidol causes a powerful motor sedation, which is useful to reduce symptoms of motor agitation and even in cases of pain.
This medicine is mainly used for the treatment of schizophrenia and its positive symptoms, these being understood as those that could be considered something that alters and excites the patient, added to the content of their thinking, speech or behavior: hallucinations, delusions, agitation, Acceleration or distracted speech, neat and shallow. Haloperidol, however, like most conventional antipsychotics, does not have great effects on negative symptoms (those that "take away" something from the patient, causing slowness, speech poverty, anhedonia or lack of logic).
Mechanism of action
Haloperidol acts by blocking dopamine receptors in the mesolimbic pathway, specifically D2 receptors, a fact that it involves the suppression of positive symptoms (especially hallucinations and delusions) by reducing an excess of dopamine in this brain system.
However, haloperidol has a non-specific action, that is, it does not only block the receptors of the mesolimbic pathway but also has an effect on other pathways, which can cause unwanted side effects.
Side effects and risks
Like most psychotropic drugs, haloperidol has a series of secondary symptoms or possible adverse effects. Likewise, like most of the typical antipsychotics, the effect of the action on dopamine blockade has possible repercussions in different systems.
Specifically, its performance on the nigrostriado circuit causes effects related to movement such as slowness, incoordination, hypertonia or muscular rigidity, or even tremors and restlessness . Thus, it is possible that a bad reaction to this medication may cause extrapyramidal syndrome, causing the above symptoms together with gestural inexpressiveness, static attitude, speech and writing difficulties and lack of reflexes. It is possible to control these symptoms with antiparkinsonians. In addition, it can cause akathisia or constant motor restlessness, akinesia or lack of movement and tardive dyskinesias, involuntary movements of the facial muscles that imitate grimaces and masticatory gestures, among others.
At the tuberoinfubular level, where haloperidol also acts even though there is no alteration in psychotic episodes in this pathway, the production of prolactin increases, which affects the reproductive system and can cause gynecomastia (growth of the breasts in men) galactorrhea or emission of milk by the breasts (even in males) and the absence of menstruation or amenorrhea.
Apart from this, Its powerful sedative effect can cause a rejection by patients , since it decreases the level of consciousness and therefore sometimes flattens affection and personal abilities.
Malignant Neuroleptic Syndrome
Although it is very uncommon, The possible side effect that can entail the greatest danger is Malignant Neuroleptic Syndrome . This picture of great severity usually appears shortly after the start of treatment with the drug. It causes muscle rigidity, high fever, tachycardia, arrhythmia and can lead to death in 20% of cases. For causes such as this it is essential to perform a correct graduation of the administration of antipsychotics.
Pros and cons of its use
Although these antipsychotics usually have greater side effects than the atypical ones, given that the latter only act at the mesolimbic-mesocortical level, while the typical ones such as haloperidol also affect the nigrostriatal system, they continue to be applied in cases with resistance to atypical neuroleptics. As already mentioned, its function is based on the treatment of positive symptoms, causing little improvement in negative symptoms .
It should be remembered that these are possible side effects, which do not have to occur but that must be assessed and that can cause the change of medication. However, haloperidol has a very powerful action that can make it very useful to control certain symptoms, being able to use both in psychotic disorders such as schizophrenia as in other problems and conditions.
Apart from its application in schizophrenia, haloperidol can be used in a large number of problems due to its various properties. This medicine It is very useful in the treatment of acute psychoses and other psychiatric disorders .
Due to its sedative properties, it has been used occasionally when the usual therapies have no effect on cases of severe anxiety. It has also been used occasionally as an anesthetic and even to treat chronic pain. In the same way, it is used as a sedative in states of great motor agitation, as in cases of manic episodes or delirium tremens.
It also serves as an antiemetic, that is, as a mechanism to prevent vomiting in those cases or syndromes in which the cessation of the vomiting process is necessary.
It is also used for the treatment of tics, Tourette syndrome, stuttering or Huntington's disease in order to control involuntary spasmodic movements.
Contraindications of haloperidol
Haloperidol is contraindicated during pregnancy . It will only be applied in these cases if there are no other alternatives. It is also contraindicated during lactation since it is excreted through breast milk. In case of specifying the use of haloperidol, it is necessary to consider the risks and the possibility of not applying breastfeeding.
Due to its powerful action, haloperidol is not recommended for patients who have to take a car or motorbike, as sedation and decreased mental alertness can have serious repercussions on driving ability.
Its potency also makes it not recommended in cases with liver or kidney failure. In the same way it can have serious repercussions of mixing with barbiturates, analgesics, morphine, antihistamines or benzodiazepines, among others.
Also, in patients with hypersensitivity to antipsychotics, cases of coma or depression of the nervous system due to alcohol and other drugs or patients with previous lesions in the basal ganglia is also contraindicated, and its harmful effects may be.
Medication taking pattern
The taking of haloperidol, as well as that of any antipsychotic, must be regulated with great precision in order to avoid or minimize the existence of dangerous secondary symptoms. Although the dose in question will depend on the problem to be treated, the general pattern will be as follows:
In acute phases of the disorder, a certain dose is recommended, powerful enough to control the symptoms , repeating the same dose until the descent of the outbreak or symptoms.
It is advisable to wait around six weeks in order to determine if the medication has the expected effects, being able to switch to another antipsychotic if not.
Once the acute phase of the disorder is over, the dose applied will be reduced as the symptoms are withdrawn until reaching a maintenance dose, which is recommended to maintain in order to avoid relapses.
In the case of patients resistant to taking medication due to low awareness of disease, a depot presentation of haloperidol can be applied, introducing a preparation that is injected intramuscularly, producing a slow release of the medication.
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