Easy is Good
The full list of ONC approved RxNorm drug and drug-class codes at your finger tips. Just start typing and the list auto-filters for a quick selection. If you know the complete drug, e.g., Penicillin V Sodium, you can select it, otherwise, just pick the drug class as allergies are based on ingredients. The system will date and time stamp your entry, and give you the opportunity to make additional notes and adjust the severity ... if necessary.
Optionally, you can define CDS rules that will fire when an allergy is added, e.g., you could build a rule to alert the provider based on a drug allergy, and/or a combination of other factors including demographics, medications, lab results, and medical conditions.
Because you may also want to enter allergies that are not on the offical list, e.g., food, or 'other', you can ...