Friday, June 12, 2015

Mechanisms of Anti-Psychotic Drug Induced Sedation (sleepiness,grogginess) (Management and Reversal of AntiPsychotic Sedation)

Sedation is a common side-effect associated with anti-psychotic drugs, both typical and atypical(1)(2). Zyprexa ( OLANZAPINE ), Seroquel ( QUETIAPINE ) and Clozapine tend to a more pronounced sedative effect than Risperdal (Risperidone) and Haldol ( HALOPERIDOL ) , depending on the dose and method of administration(3). Thorazine is typically regarded as the strongest sedative out of all of them(4)(5) (6)

However, there is debate and controversy about this, given the administration is almost always intramuscular or subcutaneous and is not typically used orally in contrast to the other medications available for typical events.

In regards to anti-histamine effects solely, Hydroxyzine AKA Vistaril seems to be the most potent.

Amisulpride and Abilify seem to be the least on the sedation scale, so substituting the above medications with either amisulpride or abilify seems like a reasonable mediation.

The mechanisms of sedation are generally, in ranked order, H1 antagonism (anti-histamine activity) (7), Alpha-1-adrenergic blockade (blocking stimulant effects of adrenaline)(8)(9), serotonin 2A antagonism (10) (blocking stimulatory effects and hallucinogenic effects of serotonin) - finally, anticholinergic effects as in with clozapine mediate the high rate of remission and sedative effects as well as weight gain(11)(12)(13).




A collaborative effort is necessary to improve patient well-being and cognitive functions in those taking sedative psychotropic medications. The mechanisms should be taken into consideration based on the patients history and individual need assessment. Adjunct treatments should be discussed to help eliminate daytime drowsiness in patients.



Some of these treatments may include.

Histamine H3 Antagonists(!); though it may not fully eliminate the sedative effects - it can certainly reduce the sedation and improve cognitive function in patients with schizophrenia and other psychiatric disorders such as ADHD(14) (15).

An example may be something as simple as supplementing with Hollarhena extract which contains a natural H3R antagonist compound(16). Patient should be monitored and the supplement should be taken during the day.

Additionally, histamine H3 antagonists like betahistine may target and attenuate anti-psychotic induced weight gain(17).

ALPHA-2-ANTAGONISTS; Caution in those with bipolar disorder or those taking clonidine, as alpha-2-antagonists will also block the effects of clonidine, not just the sedative effects(18).

A2-Antagonists may also improve cognitive function and symptoms of depression(19), especially that which is induced by adrenergic blocker drugs. They also may improve treatment outcomes and symptoms of psychosis(20)(21).

One, Idazoxan may help counter sedative effects however it is unavailable in most areas except by special order, custom synthesis or a compound pharmacy.

Alternatively, yohimbine (USA), or mianserin (U.K) could be used but careful observation and caution must be exercised. 

GABA-A Antagonism; very very risky, but will provide an almost definite reduction / reversal in anti-psychotic induced sedation. However, it can not be done in patients who have a risk of seizures or previous seizure disorder and can not be used by those with anxiety disorders..which severely limits the therapeutic application indices and restricts the the number of target patients(!).


Ginkgo biloba possesses a wakefulness effect as well as a GABA-A antagonist effect (!) - and it may exert a pro-histamine effect (!) as well which may be a very effective method to reduce antipsychotic sedation however the doses may be tricky to gauge in many patients(!).


Finally, opiate antagonist drugs such as naltrexone may help to reverse or treat anti-psychotic induced weight gain as well as tardive dyskinesia(22)(23). They may also improve/reduce sedation to a degree(24).









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