Antipsychotic-induced extrapyramidal syndromes in psychiatric practice: a case-control study

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Psychiatry

Background:

• Atypical antipsychotics are generally considered to have a lower risk of extrapyramidal side effects (EPS) compared to classical antipsychotics.
• However, this finding is not universally accepted, prompting further investigation into comparative EPS risks.

Purpose of the Study:

• To compare the risk of extrapyramidal side effects (EPS) among different subgroups of antipsychotic medications.
• To investigate potential discrepancies in EPS risk between real-world data and previous clinical trial findings.

Main Methods:

• Utilized automated dispensing records from a large psychiatric hospital in The Netherlands.
• Identified cases as first-time users of anticholinergic antiparkinson drugs and controls as non-users of such medication.
• Compared previous antipsychotic use and relevant co-factors between cases and controls.

Main Results:

• Antipsychotic users were significantly more likely to require anticholinergic antiparkinson medication (OR: 10.1).
• Low potency antipsychotics showed a lower odds ratio for EPS (3.0) compared to high potency ones (10.8).
• Both classical and atypical antipsychotics demonstrated comparable odds ratios for EPS (10.0 and 8.0, respectively), with lower equivalent doses than in prior trials.

Conclusions:

• Low potency antipsychotics are associated with a substantially lower risk of EPS.
• The expected reduced EPS risk with atypical antipsychotics was not observed, potentially due to the high and non-equivalent doses of classical antipsychotics used in previous studies.