Dyspnea, or shortness of breath, is very common in patients at the end stages of terminal diseases that can be very distressing for the patient as well as care givers. Treatment for this can include morphine or other opioids used to target receptors in the lungs by using an inhaled form or possibly using sublingually or through other routes. Lung opioid receptors: pharmacology and possible target for nebulized morphine in dyspnea.
https://www.ncbi.nlm.nih.gov/pubmed?term=10855942
