 <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]  when to start or stop taking this medication. A product that may interact with this drug is: rolapitant. Guaifenesin and dextromethorphan are available in both prescription and nonprescription products. Check the labels of all your medications to make sure you are not taking more than one product containing guaifenesin or dextromethorphan. Guaifenesin may interfere with certain lab tests (such as urine levels of certain acids), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug. Does Antitussive DM interact with other drugs you are taking? Enter your medication into the WebMD interaction checker Check InteractionThe overdose of Antitussive DM 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 center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: extreme drowsiness, blurred vision, confusion, hallucinations, slow/shallow breathing, seizures.  Notes If your doctor prescribed this medication, do not share this medication with </s>