Elsevier

Medicine

Volume 40, Issue 3, March 2012, Pages 105-106
Medicine

Specific substances
Antipsychotic drugs

https://doi.org/10.1016/j.mpmed.2011.12.006Get rights and content

Abstract

Antipsychotic drugs can be classified by chemical structure and receptor specificity. Older phenothiazine antipsychotics act on a wide range of receptor systems, whereas the newer butyrophenone and atypical drugs are more specific, particularly at dopamine receptors. In overdose, adverse events include acute extrapyramidal reactions, sedation and cardiovascular effects including, potentially, arrhythmias. Phenothiazine antipsychotics often have anticholinergic, antihistamine and α-adrenoceptor antagonist activity resulting in greater toxicity in overdose.

Section snippets

Clinical features

  • Extrapyramidal effects may occur even with therapeutic doses of antipsychotic drugs. These include acute dystonic reactions (more common in young individuals), parkinsonism (more common in the elderly) and tardive dyskinesia, which is not a feature of acute poisoning, and will diminish if an acute overdose is taken in a patient with this condition.

  • Symptoms and signs more specifically related to overdose (Table 1) include CNS and respiratory depression, hypotension, cardiac arrhythmias (usually

Management

Following overdose a variety of presentations may be seen. Acute dystonic reactions respond to intravenous diazepam or to an anti-cholinergic agent (e.g. benztropine). Specific drug therapy is usually not indicated for parkinsonian features, which often improve on withdrawal of the offending agent. Therapy for overdose is supportive.

After correcting acidosis with sodium bicarbonate, the preferred treatment for arrhythmias caused by antipsychotic drugs (usually torsade de pointes) is intravenous

References (11)

There are more references available in the full text version of this article.
View full text