Which of the following are examples of anticholinergics?

Anticholinergics are a class of medication that block the action of acetylcholine, a neurotransmitter involved in many functions, including muscle movement and the regulation of certain bodily functions. They are often used in the treatment of conditions such as Parkinson's disease and for various movement disorders.

Trihexyphenidyl and benztropine are both examples of anticholinergics. Trihexyphenidyl is often prescribed to help alleviate muscle rigidity and tremors in patients with Parkinson's disease by reducing cholinergic activity in the central nervous system. Similarly, benztropine is also used for the same purpose, helping to restore the balance between acetylcholine and dopamine in the brain, which is often disrupted in Parkinson's.

In contrast, the other options contain medications that either do not act as anticholinergics or serve entirely different purposes. For example, clonidine is an alpha-2 adrenergic agonist, pramipexole is a dopamine agonist used primarily for Parkinson's and restless leg syndrome, carbidopa and levodopa are dopaminergic agents used in conjunction to manage Parkinson's symptoms, and rivastigmine and donepezil are cholinesterase inhibitors used