SIDE EFFECTS. Serious adverse reactions associated with codeine are respiratory depression and, to a lesser degree, circulatory depression, respiratory arrest, shock, and cardiac arrest. Codeine is an opiate pain medication that's sometimes referred to as a narcotic. Its active ingredient is found in many different medications that treat pain, cough, and diarrhea. Fatal side effects can occur if you use codeine with alcohol, or with other drugs that cause drowsiness or slow your breathing. What is codeine? Codeine is an opioid pain medication. The possible side effects of Codeine Sulfate Tablets: Constipation, nausea, sleepiness, vomiting, tiredness, headache, dizziness, abdominal pain. Call your healthcare provider if you have any of these symptoms and they are severe. Fatal side effects can occur if you use opioid medicine with alcohol, or with other drugs that cause drowsiness or slow your breathing. What should I discuss with my healthcare provider before taking codeine? Codeine has a risk for abuse and addiction, which can lead to overdose and death. Codeine may also cause severe, possibly fatal, breathing problems. To lower your risk, your doctor should have you. Find information about common, infrequent and rare side effects of Codeine Sulfate Oral. These are not all the pos sible side effects of codeine sulfate. Call your doctor for medical advice about side effects. You Call your doctor for medical advice about side effects. You SIDE EFFECTS. Serious adverse reactions associated with codeine are respiratory depression and, to a lesser degree, circulatory depression, respiratory arrest, shock, and cardiac arrest. For the Consumer. Applies to codeine: oral solution, oral tablet. Along with its needed effects, codeine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.