High doses of which medication class are known to produce Parkinson's-like effects?

The correct choice is indeed related to phenothiazines, which are a class of antipsychotic medications. These drugs work primarily by blocking dopamine receptors in the brain, particularly the D2 receptor. When administered at high doses, the blockade of dopamine pathways can lead to a deficiency of this crucial neurotransmitter, resulting in movement disorders that resemble Parkinson's disease. Symptoms can include tremors, rigidity, bradykinesia, and other motor function impairments that are characteristic of Parkinsonian syndromes.

The phenomenon of drug-induced movement disorders akin to Parkinson's is well-documented with phenothiazines, making them a significant concern in pharmacological treatment, especially for patients requiring long-term antipsychotic medication. Understanding this connection is essential for healthcare practitioners to manage and mitigate side effects effectively.

The other medication classes listed do not have a well-established link to inducing Parkinson's-like effects in the same manner. Calcium channel blockers, SSRIs, and antiepileptics do not primarily target dopamine pathways and thus are not associated with the same type of side effects as high doses of phenothiazines.