 <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]  unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.The uses of Meperidine (PF) Injection: Meperidine is used to help relieve moderate to severe pain. It may also be used before and during surgery or other procedures. Meperidine belongs to a class of drugs known as opioid analgesics and is similar to morphine. It works in the brain to change how your body feels and responds to pain.Meperidine should not be used to treat long-term or ongoing pain. It should only be used to treat sudden episodes of moderate to severe pain. See also Precautions section.This drug is not recommended for use in newborns due to an increased risk of serious side effects. Ask the doctor or pharmacist for details. How to use Meperidine HCL Vial This medication is given by injection into a vein, into a muscle, or under the skin as directed by your doctor. If you are giving this medication to yourself at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to </s>