Codeine 30 mg is used for the treatment of extreme pain. It also helps reduce coughing and is also used to treat diarrhea. Codeine medicines are not for the use of children. Anyone aged above 12 can use this. Inform your doctor if you are taking Valium, anti-anxiety medicine Xanax, Ativan, Lexapro, Luvox, Klonopin, sleeping pills like Halcion and Sonata, or any other medicine. Misuse or overdose of this medicine can be fatal. Stop use of it and consult your doctor if you are getting any harmful side effects. You should inform your doctor about your other health issues before prescribing this.