| What is Amisulpride? |
| Amisulpride is a second generation antipsychotic, a
substituted benzamide. Amisulpride appears to be an
effective agent in treating schizophrenia for what
are characterised as positive and negative symptoms.
The recommended doses are between 400 mg/day and 800
mg/day. Amisulpride demonstrates a good global
safety profile, particularly when compared with
first generation antipsychotics, such as
haloperidol. There are interesting studies that
point towards amisulpride's antidepressant effect in
dysthymia and one could speculate on possible roles
in affective psychoses and chronic fatigue syndrome. |
| How does Amisulpride work? |
| Amisulpride has dual dopamine blockade and a unique
therapeutic profile being antipsychotic, at high
doses, and disinhibitory, at low doses - at low
doses (< or = 10 mg/kg) amisulpride preferentially
blocks presynaptic dopamine autoreceptors that
control dopamine synthesis and release in the rat,
whereas at higher doses (40-80 mg/kg) postsynaptic
dopamine D2 receptor occupancy and antagonism is
apparent. It binds selectively with a high affinity
for human dopaminergic D2 (Ki = 2.8 nM) and D3 (Ki =
3.2 nM) receptors and is devoid of affinity for D1,
D4 and D5 receptor subtypes. It has no affinity for
serotonergic alpha-adrenergic, H1 histaminergic or
cholinergic receptors. Amisulpride acts
preferentially on presynaptic receptors increasing
dopaminergic transmission at low doses. |
|
| There are two absorption peaks - one hour post-dose
and a second 3-4 hours after taking the tablet. The
elimination half-life is 12 hours. Absolute
bioavailability is 48%. |
|
| Amisulpride is weakly metabolised by the liver.
There are two inactive metabolites. The drug is
mainly eliminated unchanged by the kidney. 50% of an
iv dose is eliminated by the kidney-of which 90% is
eliminated in the first 24 hours. |
| |
| What is Amisulpride used for? |
| Amisulpride is used for the positive and negative
symptoms of acute and chronic schizophrenia in
adults. Though there are prescriptions of
amisulpride outside licensed indications and there
are reports of amisulpride 's unofficial use for
other conditions. |
|
| Efficacy of Amisulpride in schizophrenia |
| In an experiment, amisulpride was compared with
flupenthixol a conventional antipsychotic. The
study ran for 6 weeks and involved 132 patients
suffering from acute schizophrenia (DSM-III-R) with
predominant positive symptomatology. Doses were
initially fixed (amisulpride: 1000 mg/day;
flupenthixol: 25 mg/day) but could be reduced by 40%
in case of side effects (mean daily doses:
amisulpride: 956 mg; flupenthixol: 22.6 mg).
Intention-to-treat evaluation demonstrated
significant improvement under both medications.
ANCOVA analysis showed that reductions of BPRS
scores were more pronounced under amisulpride. Due
to adverse events, significantly fewer amisulpride
patients (6%) were withdrawn from the study (flupenthixol:
18%). Extrapyramidal tolerability was better in the
amisulpride group. |
|
| Precautions of Taking Amisulpride |
| In the elderly amisulpride can cause hypotension and
sedation. There are no systematic published data on
efficacy in children less than 15. |
|
| Renal impairment significantly reduces the clearance
and prolongs the elimination half-life of
amisulpride and risperidone (Caccia, 2000). If there
is renal insufficiency there should be a reduction
in the dose of amisulpride. The dose should be
halved if the creatinine clearance is between 30-60
ml/min and reduced to a third for clearances between
10-30 ml/min. |
|
| Prescription should be avoided if there is proven
hypersensitivity to the drug, a prolactin dependent
tumour, phaeochromocytoma, pregnancy or lactation. |
|
| Amisulpride's Comparison with other antipsychotics |
| Compared to the previous gold standard antipsychotic
haloperidol, amisulpride has a superiority in
treating schizophrenia in terms of positive and
negative symptoms and a more acceptable side effect
profile. Amisulpride also have a beneficial effect
on the quality of life measured by the Quality of
Life Scale and the Functional Status Questionnaire. |
| |
| Amisulpride side effects |
| Insomnia, anxiety, agitation are common side effects
of amisulpride. Somnolence, constipation, nausea,
vomiting and dry mouth may occur in up to 2% of
patients. Other side effects of amisulpride include
weight gain, acute dystonia, extrapyramidal side
effects, tardive dyskinesia, hypotension,
bradycardia and QT prolongation. |
|
| Amisulpride can cause hyperprolactinaemia and thus
may lead to galactorrhoea, gynaecomastia, breast
pain and amenorroea. Amisulpride's endocrine effects
are remarked on throughout the relevant literature. |
|
| Amisulpride may reduce reaction time in those using
machinery. Seizure threshold reduction. May
exacerbate Parkinson's disease. Neuroleptic
malignant syndrome is a rare though possible side
effect. |
|
| Interactions of Amisulpride |
| Co-administered ethanol increased the AUC by over
10%. There are no apparent interactions with
benzodiazepines. |
|
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Amisulpride Clinical Trials
Amisulpride Patents |
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| Disclaimer: |
| Information on this page is provided for general
information purposes. You should not make a clinical
treatment decision based on information contained in
this page without consulting other references
including the package insert of the drug, textbooks
and where relevant, expert opinion. We cannot be
held responsible for any errors you make in
administering drugs mentioned on this page, nor for
use of any erroneous information contained on this
page. |
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