Call for comparative atypical antipsychotic trials
Further evidence to help prescribers decide which atypical antipsychotic agent is best for an individual patient is urgently needed, according to a review in this month’s Drug
and Therapeutics Bulletin, because each agent has a different side effect profile.
The bulletin says that, except for clozapine in treatment-resistant schizophrenia,
head-to-head studies have not shown a convincing efficacy advantage for
any one atypical antipsychotic over another. Increasing use, however,
has revealed differing side effect profiles for each agent.
A review of the available evidence allows the bulletin to make some provisional
recommendations. Where hyperprolactinaemia is a problem, prolactin-sparing
drugs, such as quetiapine (Seroquel), olanzapine (Zyprexa) or aripiprazole
(Abilify) may help. Quetiapine, along with amisulpiride (Solian), may
also be a good choice when daytime sedation needs to be avoided.
Weight gain, says the DTB, appears to be most common with clozapine and
olanzapine and less of a problem with amisulpiride and risperidone (Risperdal).
These two agents also have a lower tendency to aggravate glucose intolerance
or dyslipidaemia. For patients in whom postural hypotension could be
dangerous, the DTB recommends avoiding atypical antipsychotics with alpha1
adrenoceptor-blocking properties (ie, clozapine, olanzapine, quetiapine,
risperidone, sertindole [Serdolect] and zotepine [Zoleptil]).
Despite this provisional guidance, DTB says the need for more evidence
is urgent. “There is a clear need for appropriate clinical trials
to clarify differences between currently available drugs,” it concludes
(2004;42:57). |
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