Fastrip is a fast-acting liquid medication used to treat moderate to severe pain. It is a sterile non-pyrogenic solution containing 150 mg of morphine sulfate per 10 mL of liquid. It can be taken orally, intravenously, intramuscularly, subcutaneously, or rectally. Fastrip may also be used off-label to treat other conditions such as coughing and diarrhea. It works by blocking pain signals sent from the body to the brain, reducing pain sensation and allowing the patient to manage their pain. It may cause dizziness, lightheadedness, constipation, and nausea.