Good points Dub. BTW the expiration date on any drug/medicine has more to do with efficacy than adverse effect. Potency is test at different stability time points. The expiration date represents the longest interval in which potency has been tested and found to be without acceptable limits; i.e. release limits at time zero. Firms can extend the expiration date by showing potency over a longer period of time thru additional stability studies.
Most medicines still retain some potency after the expiration date, but there is no risk of adverse effects. There cannot be if the product is OTC, by nature...because people do stupid things.
So if you have medicine that is OTC past the expiration date, the worst that can happen is that it is not as potent. No risk to your health.