Which of the following drugs would be contraindicated for the patient with cogwheel rigidity being treated with haloperidol?

Correct Answer: B

Rationale: Correct Answer: B (Carbidopa) Rationale: 1. Carbidopa is a dopa decarboxylase inhibitor commonly used with levodopa to treat Parkinson's disease. 2. Haloperidol, an antipsychotic, can worsen Parkinson's symptoms like cogwheel rigidity. 3. Combining haloperidol with carbidopa can lead to a drug interaction and exacerbate Parkinson's symptoms. 4. Amantadine, pramipexole, and benztropine are commonly used to manage Parkinson's symptoms and would not be contraindicated. Summary: A: Amantadine - Not contraindicated, can be used to manage Parkinson's symptoms. C: Pramipexole - Not contraindicated, can be used to manage Parkinson's symptoms. D: Benztropine - Not contraindicated, can be used to manage Parkinson's symptoms.

Correct Answer: C

Rationale: The correct answer is C, the mesolimbic mesocortical pathway. Aripiprazole is an atypical antipsychotic that works by blocking dopamine receptors in this pathway, reducing dopaminergic transmission. This helps alleviate positive symptoms of schizophrenia like hallucinations and delusions. The other choices are incorrect because: A: Tuberoinfundibular pathway is involved in regulating prolactin secretion, not related to schizophrenia. B: Locus ceruleus is primarily involved in noradrenergic neurotransmission, not the main target for antipsychotics. D: N/A is not a valid answer and does not provide any relevant information.

Correct Answer: C

Rationale: The correct answer is C: Amitriptyline. The patient's symptoms suggest anticholinergic toxicity, which aligns with amitriptyline's side effects due to its strong anticholinergic properties. Amitriptyline can cause dry mouth, blurred vision, urinary retention, and confusion. Bupropion (A) is unlikely to cause these specific symptoms. Mirtazapine (B) is more sedating than anticholinergic. Paroxetine (D) is an SSRI and does not typically cause anticholinergic toxicity.

Correct Answer: A

Rationale: The correct answer is A: Blockade of M receptors. The enteric nervous system predominantly utilizes muscarinic receptors to regulate gastrointestinal motility. Blocking these receptors can lead to adverse effects such as constipation, as it disrupts normal peristalsis. Increased serotonergic activity (B) would typically enhance gastrointestinal motility. Activation of β receptors (C) would enhance smooth muscle relaxation, potentially improving motility. Increased adrenergic activity (D) could also enhance motility due to the role of adrenergic receptors in promoting smooth muscle contraction. However, the adverse effect described in the question is more likely to be caused by the blockade of M receptors, making choice A the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Clonidine. Clonidine is an alpha-2 adrenergic agonist, which means it acts by stimulating presynaptic alpha-2 receptors, leading to a decrease in norepinephrine release. This matches the drug described in the question that blocks presynaptic alphareceptors. Amitriptyline (A) is a tricyclic antidepressant that primarily acts by blocking the reuptake of serotonin and norepinephrine. Bupropion (C) is an atypical antidepressant that inhibits the reuptake of dopamine and norepinephrine. Mirtazapine (D) is a noradrenergic and specific serotonergic antidepressant that enhances serotonin and norepinephrine activity through different mechanisms. Therefore, Clonidine is the most likely drug given due to its action on presynaptic alphareceptors, while the other choices have different mechanisms