Benzhexol and side effects with long-acting fluphenazine therapy

Area of Science:

• Psychiatry
• Clinical Pharmacology

Background:

• Fluphenazine enanthate is a long-acting antipsychotic used for chronic conditions.
• Benzhexol is an anticholinergic medication often prescribed to manage extra-pyramidal side effects of antipsychotics.

Purpose of the Study:

• To investigate the effects of withdrawing benzhexol in patients receiving fluphenazine enanthate.
• To assess the reliability of extra-pyramidal sign ratings and symptom checklists.

Main Methods:

• A double-blind, placebo-controlled study involving 16 patients on fluphenazine enanthate and benzhexol.
• Patients were divided into two groups; one received placebo instead of benzhexol.
• Assessments included the Simpson rating scale for extra-pyramidal signs and a symptom checklist.

Main Results:

• Four out of eight patients experienced severe adverse reactions upon benzhexol withdrawal.
• Symptoms like tremor and daytime sleepiness remained unchanged in all patients.
• The remaining four patients tolerated benzhexol withdrawal without adverse effects.

Conclusions:

• Acute withdrawal of benzhexol is not justified due to potential severe reactions.
• Regular dosage review of anti-Parkinsonian drugs is advisable.
• Long-term benzhexol use may lead to denervation supersensitivity; Parkinsonian signs might be linked to affective state.