Is it safe to take expired cough syrup prometh with codeine?

It's can harmful.. but many drugs last way beyond their exp. dates..but it may not be effective. As well as, When pharmacists place expiration dates on drugs, it's an estimate as to how long it will remain effective. They rarely perform extensive tests to determine if the drugs or packing materials will form dangerous chemicals over time. As a general rule, you should never take expired medicine. Especially not when it's almost 4 years past the expiration date. Be safe and throw them away. Or, you can play guinea pig and find out if vicodin/acetaminophen mixtures spontaneously form toxic compounds. Do you really wanna be a guinea pig? Be Careful. Hope this helps, Good Luck