Thanks for the details.
Well, most drugs can be used way past their expiry dates if stored properly and effectively under the appropriate temperatures.
The expiration date, required by law in the United States, (1979) specifies only the date the manufacturer guarantees the full potency and safety of the drug -- it does not mean how long the drug is actually safe to use.
Second, medical authorities uniformly say it is safe to take drugs past their expiration date -- no matter how "expired" the drugs purportedly are.
Pharmaceutical firms do not take any responsibility of someone who has fallen ill or had adverse effects after using an Expired pill/ tablet/ capsule. Before that any claim can be made - But still in order to check for viability and effectiveness of an expired drug you will have to run some complicated trials on the expired medication - which is obviously neither cost effective nor a very recreational use of one's time.
However, 3 years is a long time. You should get a refill. The risk as I mentioned is more with antibiotics.
In case of an emergency - and if all hell breaks loose then the use of an expired medicine can be of some benefitand justified but not if it is going to kill you or make you more ill rather than save your life or cure the illness.
A bonus and a positive feedback will be appreciated.