 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  safely. Other medications can affect the removal of guaifenesin/codeine from your body, which may affect how guaifenesin/codeine works. Examples include azole antifungals (such as ketoconazole), bupropion, fluoxetine, macrolide antibiotics (such as erythromycin), paroxetine, quinidine, rifamycins (such as rifabutin, rifampin), ritonavir, certain drugs used to treat seizures (such as carbamazepine, phenytoin), among others. This medication may interfere with certain lab tests (such as urine 5-HIAA levels, urine VMA levels, amylase/lipase levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug. Does Mar-Cof CG interact with other drugs you are taking? Enter your medication into the WebMD interaction checker Check InteractionThe overdose of Mar-Cof CG Oral: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control </s>