IV medications alone generally will not resolve VF. Recall that VF is chaotic electrical activity of the heart. The goal of defibrillation is to concomitantly depolarize all heart cells into an absolute refractory state (stop the heart) in order to allow an intrinsic myocardial pacemaker to "come on line" and begin directing organized electrical activity.

Always remember to treat the patient not the monitor. Perform effective CPR and frequently evaluate the patient during resuscitation with pulse checks, rhythm assessments, etc....