Antipsychotics are also referred to as , or simply '''neuroleptics'''. The word ''neuroleptic'' is derived from Greek ; ''neuro'' refers to the Nerve s and ''lept'' means "to take hold of". Thus the word means "taking hold of one's nerves". This term reflected the fact that the drugs commonly made movement more difficult and sluggish, which clinicians believed indicated that a dose was high enough. The lower doses used currently have resulted in reduced incidence of motor side effects and sedation and the term is less commonly used than in the past.
Typical antipsychotics are also sometimes referred to as , because some of them can tranquilize and sedate. This term is increasingly disused as the terminology implies a connection with Benzodiazepine s ("minor" tranquilizers) when none exists.
Antipsychotics are broadly divided into two groups, the Typical Or First Generation Antipsychotics and the Atypical Or Second Generation Antipsychotics . There are also Dopamine Partial Agonists , which are often categorized as atypicals.
Common conditions with which antipsychotics might be used include Schizophrenia , Mania and Delusional Disorder . They might be used to counter psychosis associated with a wide range of other diagnoses. Antipsychotics may also be used in Mood Disorder (e.g. Bipolar Disorder ) even when no signs of psychosis are present. Some antipsychotics ( Haloperidol , Pimozide ) are used Off-label to treat Tourette Syndrome .
In routine clinical practice, antipsychotics may be used as part of risk management, and to control difficult patients, although this is controversial.
The original antipsychotic drugs were happened upon largely by chance and were tested empirically for their effectiveness.
The first antipsychotic was Chlorpromazine , which was developed as a surgical Anesthetic . It was first used on psychiatric patients in the belief that it would have a calming effect. However, the drug soon appeared to reduce psychosis beyond this calming effect, and now some believe that it causes a reduction of psychosis unrelated to the sedating effect of the medication. It was introduced for the treatment of psychosis during the period when Lobotomy was a common treatment and was hailed as a "cure" for schizophrenia. It was then touted to provide a "chemical lobotomy," causing similar neurological effects without requiring surgery.
The newer atypical antipsychotics are supposedly Rationally Designed Drugs in which a theoretical understanding of both the condition to be treated and the effect of certain molecules on the body is used to develop potential new drug candidates.
Commonly used antipsychotic medications are listed below by drug group. Trade names appear in parentheses.
- --- Clozapine (Clozaril) - Requires weekly to biweekly CBC (FBC) because of risk of Agranulocytosis (a severe decrease of White Blood Cells ).
- --- Olanzapine (Zyprexa) - Used to treat psychotic disorders including schizophrenia, acute manic episodes, and maintenance of bipolar disorder. Dosing 2.5 mg to 20 mg per day. Comes in a form that quickly dissolves in the mouth (Zyprexa Zydis). May cause appetite increase, weight gain and altered glucose metabolism leading to an increased risk of diabetes mellitus.
- --- Risperidone (Risperdal) - Dosing 0.25 to 6 mg per day and is titrated upward; divided dosing is recommended until initial titration is completed at which time the drug can be administered once daily. Available in long-acting form (Risperdal Consta that is administered every 2 weeks; usual dose is 25 mg). Comes in a form that quickly dissovles in the mouth (Risperdal M-Tab). Used off-label to treat Tourette Syndrome .
- --- Quetiapine (Seroquel) - Used primarily to treat bipolar disorder and schizophrenia, and "off label" to treat chronic Insomnia and Restless Legs Syndrome ; it is a powerful sedative (if it's used to treat sleep disorders and is not effective at 200 mg, it is not going to be effective in this regard). Dosing starts at 25 mg and continues up to 800 mg maximum per day, depending on the severity of the symptom(s) being treated. Users typically take smaller doses during the day for the neuroleptic properties and larger dose at bedtime for the sedative effects, or divided in two equally high doses every 12 hours (75-400mg bid).
- --- Ziprasidone (Geodon) - Now (2006) approved to treat bipolar disorder. Dosing 20 mg twice daily initially up to 80 mg twice daily. Prolonged QT Interval a concern; watch closely with patients who have heart disease; when used with other drugs that prolong QT interval potentially life-threatening.
- --- Amisulpride (Solian) - Selective dopamine antagonist. Higher doses (greater than 400 mg) act upon post-synaptic dopamine receptors resulting in a reduction in the positive symptoms of schizophrenia, such as psychosis. Lower doses however act upon dopamine autoreceptors, resulting in increased dopamine transmission, improving the negative symptoms of schizophrenia. Lower doses of amisulpride have also been shown to have Anti-depressant and Anxiolytic effects in non-schizophrenic patients, leading to its use in Dysthymia and Social Anxiety Disorder . In one particular study, amisulpride was found to have greater efficacy than Fluoxetine in decreasing anxiety. Currently, amisulpride is approved in Europe, Australia and other countries for use in schizophrenia, and is approved and marketed in lower dosages in some countries for treating dysthymia (such as in Italy as Deniban ). Amisulpride has not been approved by the FDA for use in the United States.
- --- Paliperidone (Invega) - Derivative of risperidone. Approved in December 2006.
- Dopamine Partial Agonist s:
- --- Aripiprazole (Abilify) - Dosing 5 mg up to maximum of 30 mg has been used. Mechanism of action is thought to reduce susceptibility to metabolic symptoms seen in some other atypical antipsychotics.
- --- Under clinical development - Bifeprunox ; Norclozapine (ACP-104).
- Other options
- --- Symbyax - A combination of Olanzapine and Fluoxetine used in the treatment of bipolar depression.
- --- Tetrabenazine (Nitoman in Canada and Xenazine in New Zealand and some parts of Europe) is similar in function to antipsychotic drugs, though isn't generally considered an antipsychotic itself. This is likely due to its main usefulness being the treatment of hyperkinetic Movement Disorder s such as Huntington's Disease and Tourette Syndrome , rather than for conditions such as Schizophrenia . Also, rather than having the potential to cause Tardive Dyskinesia that most antipsychotics have, tetrabenazine can actually be an effective ''treatment'' for the condition.
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