Therapeutic dose Adult Initially 3 mg as rapid IV bolus (over 2 sec). 2nd dose: 6 mg. 3rd dose: 12 mg. The 2nd & 3rd dose should be also be given as rapid IV bolus if the 1st & 2nd dose do not result in elimination of the supraventricular tachycardia w/in 1-2 min. Diagnostic dose The above ascending dosage schedule should be employed until sufficient diagnostic information has been obtained.