A 52-year-old man from Delhi presents with acute onset of vertigo, nausea, and inability to walk in a straight line. Examination reveals dysmetria on finger-nose test, nystagmus, and past-pointing. MRI brain shows an acute infarct in the distribution of the superior cerebellar artery. His blood pressure is 168/95 mmHg, and he is in sinus rhythm. What is the most appropriate immediate next step in management?