Polyneuropathy caused by chlorprothixene

Area of Science:

• Neuroscience
• Pharmacology
• Clinical Neurology

Background:

• Antipsychotic medications are widely used in psychiatric care.
• Chlorprothixene is a typical antipsychotic with a known side effect profile.
• Neurological adverse effects of psychotropic drugs require careful monitoring.

Purpose of the Study:

• To investigate the potential link between chlorprothixene use and the development of polyneuropathy.
• To characterize the clinical and electrophysiological findings in patients experiencing neurological symptoms attributed to chlorprothixene.
• To assess the reversibility of polyneuropathy after drug withdrawal.

Main Methods:

• Case series involving seven chronic psychiatric patients.
• Clinical assessment of neurological symptoms, particularly in the lower limbs.
• Electroneuromyography (ENMG) to evaluate nerve conduction velocities and signs of denervation.
• Monitoring of symptoms following cessation of chlorprothixene.

Main Results:

• All seven patients developed polyneuropathy, primarily affecting lower limbs, after prolonged chlorprothixene treatment (3-24+ months) at doses of 500-1800 mg/d.
• Electroneuromyography revealed significantly reduced or absent motor conduction velocities in peroneal nerves and signs of denervation in leg muscles (and upper limbs in 4 patients).
• Neuropathic signs showed gradual improvement after chlorprothixene withdrawal.

Conclusions:

• Chlorprothixene may induce a dose-dependent and reversible toxic polyneuropathy.
• Early identification and discontinuation of the drug are crucial for symptom resolution.
• Further research into the neurotoxic mechanisms of chlorprothixene is warranted.