Codeine is an opioid drug that is prescribed to treat a patient’s pain and patients who have a cough and diarrhea. Normally, the medication is prescribed to treat pain ranging from mild to severe. Since Codeine is an opioid drug, you should be aware of mixing Codeine with alcohol before you buy Codeine online because the mixture could prove lethal for you. One of the symptoms of the mix are feeling drowsy. But the serious ones are that the person might collapse or even die.