This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
[{'content': 'Constipation is caused by all of the following drugs EXCEPT: \nSelect and explain. \nA. Neostigmine, B. Atropine, C. Morphine, D. Fentanyl', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Drugs causing constipation: Aluminum-containing antacids Antispasmodics e.g. dicycloverine, mebeverine, peppermint oil Colestyramine Diuretics e.g. furosemide Antihypeensive drugs e.g. clonidine, methyldopa, propranolol, verapamil Sedating antihistamines e.g. chlorphenamine, promethazine Opioid analgesics e.g. codeine, dihydrocodeine, morphine, tramadol, fentanyl Tricyclic antidepressants e.g. amitriptyline, dosulepin, imipramine Monoamine-oxidase inhibitors (MAOIs) e.g. moclobemide, phenelzine Antipsychotics e.g. amisulpride, chlorpromazine, clozapine Antiparkinson drugs e.g. entacapone, pramipexole, procyclidine, selegiline Antiepileptic drugs e.g. carbamazepine, oxcarbazepine, phenytoin, pregabalin, Alpha blockers e.g. prazosin, tamsulosin Iron preparations Calcium supplements Bisphosphonates e.g. alendronic acid, risedronate anticholinergics like atropine ESSENTIALS of medical PHARMACOLOGY SEVENTH EDITION: KD TRIPATHI Page:107,108', 'role': 'assistant'}]