5. Example - Pain medicines
Medicines that are available without prescription for pain relief (e.g. for a headache or muscle ache) are all chemical agents. These medicines are designed to work quickly with few side effects. They are most often taken as a single or short course of
tablets, although some are available as creams. They act by blocking the chemical triggers of pain and by reducing inflammation. Examples include acetylsalicylic acid, ibuprofen and paracetamol. Other pain relief medicines that are more powerful can
only be prescribed by doctors, because the patient must be carefully monitored and the medicine can be harmful. These medicines include opium and morphine derivatives (e.g. codeine), which are very effective but are associated with side effects, including
vomiting and skin reactions. Such medicines will only be given when the doctor considers pain to be a major issue and are generally administered to patients with long-term (chronic) pain.