Obtaining past medical history is just common sense.

• Previous cardiovascular disease increases the risk of arrhythmias
• Previous chronic respiratory disease will increase the adverse effects from respiratory depressant drugs
• Previous epilepsy increases the risk of seizures with proconvulsant drugs
• Previous renal or hepatic disease may reduce the clearance of some drugs
• Myotonic dystrophy is a contraindication to aminoglycoside therapy (just thrown in to see if you're still awake)