Embodiments include method, systems and computer program products for predicting adverse drug events on a computational system. Aspects include receiving known drug data from drug databases and one or more of a candidate drug, a drug pair, and a candidate drug-patient pair. Aspects also include calculating an adverse event prediction rating representing a confidence level of an adverse drug event for the candidate drug, a drug pair, and a candidate drug-patient pair, the rating being based on the known drug data. Aspects also include associating adverse event features with the candidate drug, drug pair, or a candidate drug-patient pair, including a nature, cause, mechanism, or severity of the adverse drug event. Aspects also include calculating and outputting an adverse event prediction rating.