A patient allergic to Cogentin and Artane, who feels drowsy from Benadryl, is prescribed which medication for neck stiffness from antipsychotic use?

The correct medication for treating neck stiffness due to antipsychotic use in this scenario is Symmetrel. This medication, also known as amantadine, is an antiparkinsonian drug that can be effective in alleviating the extrapyramidal symptoms associated with antipsychotic medications, including neck stiffness or rigidity.

In the context provided, the patient has allergies to Cogentin (trihexyphenidyl) and Artane (trihexyphenidyl), both of which are anticholinergic medications commonly used to treat such symptoms. Given the patient's allergies, prescribing these medications would not be appropriate or safe. Additionally, while Benadryl (diphenhydramine) can help manage some extrapyramidal symptoms due to its anticholinergic properties, the patient experiences drowsiness from it, making it an unsuitable option as well.

Symmetrel is a preferable choice because it does not have the same anticholinergic side effects and can offer effective relief from the stiffness without the concern of allergic reactions or exacerbating drowsiness, thus making it the optimal alternative in this case.