Propranolol - Oral dose is 2-6 mg/kg/day
But, the IV dose is 0.01 - 0.1 mg/kg/dose - slow IV over 10 minutes. Max. 1 mg (infants) & 3 mg (children), 5 mg (adults - to be given as 1 mg alliquots slow IV x repeat every 5 min)
IV dose is much lower than oral dose because of the extensive first-pass metabolism in the liver. Therefore, bioavailability of orally-administered Propranolol is much lower (30-40% of administered dose, higher in Down's syndrome).
Beware, IV Propranolol is a frequently over-dosed medication by doctors! (Mostly due to ignorance). This occurs mostly when a patient is receiving oral Propranolol and is NPO for some reason. Someone (a physician) writes the same oral dose to be given IV. Generally, overdosed approx. 10-fold!