 <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]  Ondansetron injection should be clear and colorless. If you are using the premixed bags, after removing the bag from the outer wrapper, check for small leaks by squeezing the container firmly. Before using, check visually for leaks, particles, or discoloration. If these are present or the container is damaged, do not use the liquid. Learn how to store and discard medical supplies safely. To prevent or treat nausea after surgery, a single dose of ondansetron may be given undiluted into a muscle or vein (IV) shortly before the start of surgery, during surgery, or after surgery by a health care professional. Dosage is based on your weight, medical condition, age and response to treatment. Tell your doctor if your condition does not improve or if it worsens.The side effects of Ondansetron HCl (PF) Injection: Headache, fever, lightheadedness, dizziness, drowsiness, tiredness, constipation, or redness/pain/burning at the injection site may occur. If these effects last or get worse, tell your doctor promptly. Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects </s>