This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adrenergic System, Subject name: Pharmacology
[{'content': 'Propranolol is useful in all except \nSelect and explain. \nA. Atrial flutter, B. Parkinsonian tremor, C. Thyrotoxicosis, D. Hypertrophic cardiomyopathy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (B) Parkinsonian tremor(Ref: KDT 8th/e p164)Propranolol is useful in the management of tremor due to overdose of sympathomimetic agents (b2 mediated). Metoprolol as well as propranolol are effective in essential or familial tremor (b1 mediated). b -blockers are ineffective in intention tremor and rest (parkinsonian) tremors.', 'role': 'assistant'}]