Drug of choice in anaphylactic shock is?

Intravenous Adrenaline REF: Harrison's Internal Medicinel7th ed> Chapter 311. Allergies, Anaphylaxis, and Systemic M astocytosis Anaphylaxis: Treatment Mild symptoms such as pruritus and uicaria can be controlled by administration of 0.3 to 0.5 mL of 1:1000 (1.0 mg/mL) epinephrine SC or IM, with repeated doses as required at 5- to 20-min intervals for a severe reaction An IV infusion should be initiated to provide a route for administration of 2.5 mL epinephrine, diluted 1:10,000, at 5- to 10-min intervals, volume expanders such as normal saline, and vasopressor agents such as dopamine if intractable hypotension occurs. When epinephrine fails to control the anaphylactic reaction, hypoxia due to airway obstruction or related to a cardiac arrhythmia, or both, must be considered Oxygen alone a nasal catheter or with nebulized albuterol may be helpful, but either endotracheal intubation or a tracheostomy is mandatory for oxygen delivery if progressive hypoxia develops. Ancillary agents such as the antihistamine diphenhydramine, 50 to 100 mgIM or IV, and aminophylline , 0.25 to 0.5 g IV, are appropriate for uicaria-angioedema and bronchospasm, respectively. Intravenous glucocoicoids, 0.5-1.0 mg/kg of medrol, are not effective for the acute event but may allete later recurrence of bronchospasm, hypotension, or uicaria.