A patient with theophylline poisoning developed hypotension. Drug of choice in theophylline poisoning with hypotension is:

Acute overdose of theophylline is characterized by hypotension, tachycardia, and hypokalemia. Treat hypotension with intravenous fluids. Propranolol, 0.02-0.05 mg/kg, or esmolol, 25-50g/kg/min, intravenously, may reverse hypotension associated with tachycardia, both of which are mediated by excessive beta adrenergic stimulation. By contrast, chronic intoxication more commonly results in seizures and arrhythmias with much lower serum levels (ie, 20-70 mg/L). Hypotension and hypokalemia are uncommon. Must know: Theophylline, caffeine, and other methylxanthines cause bronchodilatation; gastric, central nervous system, and cardiac stimulation; and vasodilatation. The minimum acute toxic dose is over 10 mg/kg, or 700 mg, in the average adult. Ref: Morgan D.L., Borys D.J. (2011). Chapter 47. Poisoning. In R.L. Humphries, C. Stone (Eds), CURRENT Diagnosis & Treatment Emergency Medicine, 7e.