Which medication is most likely to cause poor muscle coordination and slow movements?

Haloperidol is an antipsychotic medication primarily used to treat schizophrenia and other psychiatric disorders. One of its side effects is the potential to cause extrapyramidal symptoms (EPS), which include poor muscle coordination, rigidity, tremors, and slow movements, often resembling symptoms of Parkinson's disease. These effects are due to haloperidol's mechanism of action as a dopamine antagonist in the central nervous system, particularly affecting the areas of the brain that control motor functions.

Nifedipine is a calcium channel blocker used to treat hypertension and angina and is not typically associated with muscle coordination effects. Venlafaxine, an antidepressant belonging to the serotonin-norepinephrine reuptake inhibitor (SNRI) class, may cause various effects including some potential for agitation, but it is not commonly linked with significant motor coordination issues. Prazosin, primarily used for hypertension and PTSD, can cause side effects like dizziness but does not typically result in motor coordination disturbances.

This context highlights how haloperidol's pharmacological effects are distinctly associated with the movement-related side effects in comparison to the other medications listed.