Hello, Welcome to healthcare magic. Atenolol, Lisinopril and Amlodipine could all cause drug reactions of different types. If you had anaphylactic shock 3 weeks back, it is unlikely that the implicating drug could be atenolol as restarting the same drug could lead to a more severe anaphylactic reaction the 2 nd time. You have not described the nature of rashes. However, it is better to review your medications with your doctor and avoid the 3 groups of drugs. You could also reintroduce the drugs one at a time and see if the rashes reappear so that the offending drug can then be eliminated. Hope this helps you. Take care.