Extrapyramidal symptoms associated with calcium-channel blockers

Area of Science:

• Pharmacology
• Neuroscience

Background:

• Calcium channel blockers (CCBs) are widely used medications.
• Flunarizine and cinnarizine are specific CCBs known for potential side effects.
• Extrapyramidal symptoms (EPS) are a class of movement disorders.

Observation:

• Flunarizine and cinnarizine are frequently associated with causing EPS.
• Other CCBs rarely cause EPS.
• Inhibition of calcium influx and dopaminergic antagonism are proposed mechanisms for CCB-induced EPS.

Findings:

• The chemical structures of flunarizine and cinnarizine resemble neuroleptics, potentially explaining their higher incidence of EPS.
• Risk factors for EPS include advanced age and a family history of tremors or Parkinson's disease.
• EPS onset is unpredictable, but symptom resolution typically occurs within months of drug discontinuation.

Implications:

• Discontinuation of the offending CCB is the primary management strategy for EPS.
• Pharmacological management of EPS while continuing CCB therapy is generally ineffective.
• Close monitoring of patients on CCBs, particularly flunarizine and cinnarizine, for EPS is crucial.